1|28|Be Prudent Pruning Palms |Pruning palms is one of the standard landscape maintenance practices of spring and summer. Often it is done incorrectly, causing the palm unseen damage. %0A%0AThe tendency is to prune palms severely. Standard practice is to remove all but the top tier of leaves. In coastal areas this is called "hurricane" pruning. It is typically done just prior to the hurricane season, with the intention of protecting the palms from high winds.  %0A%0AIn reality, palms need no protection from high winds. Their flexible leaves and low wind resistance make them nearly storm-proof. But the practice of hurricane pruning continues, even in locations far away from the sea. It the Desert Southwest the practice is referred to as Arooster-tailing due to the plumed appearance of the remaining leaves. %0A%0ARooster-tail pruning is harmful in several ways. Instead of protecting the palm from high winds, the practice actually weakens the canopy. The reason for this is that all fronds (leaves) in the head of a palm act together, with each frond layer supporting and adding strength to the one above. They all protect the bud and newly emerging spear leaf. The more leaves removed, the less strength and protection there is. %0A%0ALike trees, palms manufacture their food through their leaves. But palms are not as efficient as trees at storing their food for needy times. So palms are more dependent on their leaves to provide necessary food for growth. With relatively few leaves, compared to trees, removing even one green frond can significantly reduce the palms ability to feed itself.  %0A%0AAn unpruned Mexican fan palm carries no more than 30 fronds at one time. Typically, as many as 20 fronds may be removed in "rooster-tail" pruning. That means the palms ability to manufacture food has been reduced by two-thirds. Try to imagine if you had to survive on two-thirds less calories a day! %0A%0ASevere pruning also stimulates an unhealthy survival response in palms. Energy is burned, to quickly produce new leaves to replace those lost. Instead of storing food, palms that are severely pruned begin depleting their reserves of energy. If this happens on an annual basis, the palm's trunk gradually decreases in diameter and becomes weak. It is more likely this weakened trunk will break or shatter in a storm.  %0A%0APalms also move nutrients from the older fronds to the new growth. When all of these older fronds are removed, so is the source of much of the nutrients that palms need. As a result, nutrient deficiencies can develop. These nutrient deficiencies can be difficult to correct. %0A%0AIdeally, only brown or yellowing fronds should be removed when pruning a palm. If%0Agreen fronds must be removed, prune off as few as possible. Under no circumstances should palms be severely pruned! Severe pruning is characterized by the removal of any  fronds between the 10 o'clock and 2 o'clock positions on the palm canopy. This can be visualized by imagining a clock face placed over the palm canopy, with the 12 o'lock  and 6 o'clock positions being aligned with the trunk.  %0A%0AFinally, it is important that the trunks of palms not be injured. Palms should never be climbed using spiked or cleated climbing shoes. These spikes puncture and wound the trunk, allowing the entry of pathogens that can kill the palm. Pruning should be done by knowledgeable professionals using a hydraulic bucket lift "cherry picker," pole pruners or ladders. %0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on May 16, 1999 |May 16, 1999|
2|1|Winter Problems Plague House Plants|Tired, worn-out soil has been the ruin of many a houseplant.  Potting soils are made mostly of peat and are not designed to hold up over time.  That's because potting soil peat breaks down after just a couple of years leaving plant roots with insufficient soil to grow properly.  The solution is to repot with fresh soil.  If the plant is pot-bound, with large roots growing on the outside of the root ball, step it up to a larger pot.  If you wish to use the same container, simply scrape away some of the old soil from the bottom and sides of the root ball.  Set the plant back in the same pot adding fresh soil along the bottom and inside edges.%0A%0A	Choose a quality potting soil with a mixture of peat, perlite and vermiculite.  High quality potting soils will be more expensive, but are well worth the cost.  You can also make your own potting soil by purchasing separate ingredients in small bags at garden centers and nurseries.  Mix equal parts of peat, perlite and vermiculite to and make your own potting mix.  If your potting cacti or other succulents replace the peat with sand.%0A	%0A	A build-up of salts goes hand in hand with tired soils.  Over time, salts in fertilizer and tap water accumulate in the pot.  They appear as a white crust on the soil surface, the inner pot rim, and the outer surface of clay pots.  Too much salt can cause plant leaves to burn around the margins and fall off.  If left uncorrected the plant can die. %0A%0A	Pots with a heavy buildup of salts should be discarded.  Salts should be washed out of the soil by watering heavily to dissolve them and wash them out the drainage hole.  First, water the plant with the normal amount of water.  Wait a few hours until the salts dissolve.  Then, water again heavily.  As the water flows through and out the pot, salts will be removed.  Discard this salt-laden drainage water.%0A%0A	Over watering, especially during the winter months will cause plant leaves to yellow and drop off.  It will also cause the plant to be stunted, with no new growth.  Water-soaked roots will eventually cause the whole plant to wilt and die.%0A%0A	Potting plants in a well-drained potting mix will help prevent injury from over watering.  It's also a good idea to allow plants to go a little longer between waterings than you would normally.  Most potted plants are not actively growing in the winter and thus do not require as much water as other time of the year.  I like using a moisture meter to determine when my potted plants need watering.  Moisture meters are inexpensive and available at most garden supply outlets; and best of all, they really work!%0A%0A	Watering with cold tapwater can damage plants, especially tropical house plants.  This is a problem in the winter when water pipes running into the house become cold.  Always use water that is at room temperature or slightly warm.  Some plants are also sensitive to chemicals added to our tap water.  These include chlorine or fluoride.  Letting the water set overnight will allow these chemicals to evaporate out and make the water safer to use for your house plants.%0A%0A	Chilling temperatures can also cause house plant leaves to yellow and drop off. This is especially true of plants that are located near window panes and outside doors. Move them back from these and other cold, drafty locations.  This is especially important at night and during runs of unusually cold weather.  %0A%0AFinally, if you leave on a winter holiday, be sure your plants are provided for.  Have a friend or neighbor come in and water when necessary.  Pull plants back a few feet from window panes.  Also when your away, don't set the thermostat too low.  Many tropical plants will chill if temperatures fall below 60 degrees.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. 	%0A%0AMaterial originally appeared in Arizona Daily Star gardening column, on %0AJanuary 7, 2001|August 30, 2001|
3|9|It's Time To Tidy Up The Garden|Now that Winter is fully upon us, garden and landscape activities have slowed considerably.  That makes it an ideal time to clean-up outdoors in preparation for the Spring growing season.%0A%0A	Leaf and twig litter from garden and landscape plants should be cleaned up and disposed of.  If you have a compost bin, the litter can be used to your advantage to make compost.  If not bag it up and throw it away.  Getting rid of the litter will help reduce future insect and disease problems thorough the oldest control method known: sanitation!%0A%0A	If certain garden plants have been badly infest with insects such as mites, whitefly, or scale; throw them away.  Proper composting will kill these pests, however, composting is not always thorough and these pests could reinfect the garden next spring.%0A%0A	Cleaning up weeds also provides sanitation.  More importantly, if you eliminate the weeds you'll get rid of weed seeds that could germinate later this Winter.  Many unwanted plants sprout each year, these plants are called "volunteers".  They may or may not be true weeds.  Brittlebush and desert marigold are desirable wildflowers but may become a nuisance as they pop up in uncontrolled locations in the landscape.  Others like fountain grass and desert broom are truly invasive and should be eliminated when detected.%0A%0A	Spent flowers and flower stalks should be pruned off.  Plants like penstemon, salvia, hesperaloe, bird-of-paradise, yucca and others with dried stalks of spikes can be pruned.  This grooming process keeps plants healthier and more vigorous.%0A%0A	Winter dormant perennials, such as Salvia, Calylophus, Helianthus, Rudbeckia and ornamental grasses can be cut back to near the ground.  They will regrow in the spring, producing new shoots from the basal portion of the plant.%0A%0A	Dead wood and broken branches should be pruned from evergreen trees and shrubs now.  Be careful, however, not to prune branches that just look dead.  Some freeze damaged plants, such as bougainvillea and lantana, will recover next spring.  The easiest way to tell if a branch is dead or alive, is to scratch it with your thumb nail or a sharp knife.  Live wood will reveal green sapwood beneath the bark, while dead wood will be brown throughout.  Wait until new growth begins in the spring before removing frost injured branches.%0A%0A%0A%0A	Clean up fallen mesquite twigs.  They often contain the eggs of a small gray beetle called the "twig pruner".  It these twigs are not raked up and removed, the eggs will hatch in the spring and the young pruners will move into the tree.  There feeding will cause the tips of branches to die.%0A%0A	Besides cleaning up, it's also a good time to dress up the garden with additional mulch.  Organic mulches are great for plants.  They help conserve moisture, control weeds, moderate soil temperatures, and increase organic matter.  Because they decompose over time, new mulch needs to be added to maintain a layer 3 to 4 inches thick.  Forest mulch, chunk bark, and shredded cypress make the best mulches.  Rock mulch too, needs a top-dressing of additional stone from time to time.  No one knows how it disappears, but it does!%0A%0A	Cleaning up garden debris, pruning and grooming plants, and adding mulch are important Winter gardening  activities.  Accomplishing them now, will afford you more time this coming Spring for the really fun stuff - planting!%0A%0A	The topic for this week's garden demonstration will be the "How To's" of Drip Irrigation.  It will be presented on Wednesday at 9:00 a.m. at the Pima County Extension Center, at 1:00 p.m. at the Wilmot Library, and on Thursday at 2:00 p.m. at Marana Planning Services on the Northeast corner of Orange Grove and Thornydale.  Answers to gardening questions may be obtained by phoning 626-5161 in Tucson or 648-0808 in Green Valley. %0A|April 19, 2001|
4|10|Prune Overgrown Texas Ranger Shrubs|Texas rangers are a group of beautiful shrubs that comes to us from the Chihuahuan desert of west Texas and eastern Mexico.  Cultivars vary in flower color from lavender to pink to white.  They also range in size, depending on the variety,  from 3 feet to over 10 feet tall.  %0A%0A	When left to grow naturally, Texas rangers have a beautiful shape, with thick, leafy growth, bottom to top. They also bloom the length of their stems whenever warm weather rains occur.   The problem with Texas rangers is that most people don't let them grow naturally, or hand prune them.  They are usually pruned with hedge shears.  This encourages all the growth to occur on the outer edge of the shrub, while causing the inner portions to become bare.  %0A%0A	Sheared Texas rangers bloom poorly, get bare and leggy, and become hopelessly overgrown.  The solution is to winter prune these over-grown shrubs back drastically and let them grow up the right way.  This process is called restoration pruning.%0A%0A	Now that plants are dormant they can take rather severe pruning and recover just fine.  Use long-handled loppers or a pruning saw to cut the stems of about 12 to 18 inches above the ground.  Don't worry about leaving bare, leafless stubs.  There are lots of dormant buds just under the bark on these stems near the ground.  When weather warms in the spring, they will begin to grow and develop into new shoots that will soon become the stems and branches of your restored shrub.%0A%0A	Don't use pruning paint on the cuts you make.  These products can actually be harmful to the plant.  They interfere with the plant's natural healing process.  What's worse they can be absorbed into the wood and have a toxic effect on the new growth.%0A%0A	It doesn't take long using this method to have a great looking, revived Texas ranger.   To help the plant recover, apply a high nitrogen fertilizer just prior to the onset of new growth.  In the Tucson area fertilization should be done in early to mid-March. %0A%0A	Apply one cup of ammonium sulfate (21-0-0), lawn fertilizer, or similar analysis fertilizer to each Texas ranger you prune back.  Sprinkle the fertilizer evenly over the soil, from the base of the shrub out to about 4 feet.  Immediately after applying the fertilizer water it in slowly, using a soaker hose. %0A%0A%0A	Now, to keep your Texas ranger looking it's best; don't prune!  Your shrub will grow several years before requiring any additional pruning.  And when you finally do, don't use a hedge shears.  Rather, use a hand pruners and remove only the longest stems, cutting them back well into the shrub.  This type of selective pruning will maintain the shrub at whatever size you want, while keeping it naturally attractive and flowering at it's peak.%0A%0A	Other types of shrubs that respond well to restoration pruning include; oleander, cassia, jojoba, greaswood, hopbush, buddleia, and ruellia.  Although restoration pruning is not a recommended for all shrubs, it is a method that works to restore shrubs that have been sheared and trained into balls for many years.%0A%0A	For shrubs that are simply overgrown, but not sheared, they can be hand pruned into shape with less drastic measures.  Use the selective hand-pruning method detailed above for maintaining shrubs.  You don't need to prune off too many stems and branches all at once.  Just the longest ones.  The following year you can prune using the same method.  Just be sure to make your cuts back into the center of the shrub.  Using this method, the shrub will maintain and attractive natural form.%0A%0A	The topic for this week's garden demonstration will be "Patio and Container Gardening".  It will be presented on Wednesday at 9:00 a.m. at the Pima County Extension Center, at 1:00 p.m. at the Wilmot Library, and on Thursday at 2:00 p.m. at Marana Planning Services on the Northeast corner of Orange Grove and Thornydale.  Answers to gardening questions may be obtained by phoning 626-5161 in Tucson or 648-0808 in Green Valley. %0A	%0A%0A	%0A%0A	%0A%0A|April 19, 2001|
5|21|Helping Freeze Damaged Plants Recover|Don't be too hasty to cut back freeze damaged plants. The recent cold weather caused browning on a number of cold sensitive plants. Hardest hit were bougainvillea, oleander, hibiscus, annual flowers, citrus trees and queen palms. Brown leaves are obvious, but die back of stems may not be. For this reason it's best to wait to prune back cold injured trees and shrubs until spring growth begins. Prune too early and you may be removing live wood, thus reducing the plants size unnecessarily. %0A%0ALeaving cold damaged leaves and stems on the plant until spring has another advantage. The dead leaves help hold in heat around the undamaged portions of the plant. This can reduce further cold injury if we have additional freezing weather. %0A%0AIf you must prune trees and shrubs now, carefully examine the wood to determine which parts of the plant are dead and which are alive. Start at the branch tips working inward. Scratch off a little of the bark to reveal the cambium layer. This is the living tissue which transports water and manufactured food throughout the plant. Healthy cambium should be white, creamy, light beige or green in color. If however the cambium is black or brown the stem or branch is dead at that location. Move further down towards the base of the plant, checking the cambium as you go. When you find healthy cambium wood, prune back the stem or branch slightly below the dead wood, into the healthy cambium. Check a majority of branches on each plant to determine the extent of die-back before pruning. %0A%0ACold tender flowers such as geraniums, begonias and calendulas, which were damaged, can be cut back to remove frozen growth. Removing the damaged portions of these plant will encourage new growth and flowering. Watering should be continued on a regular basis. An application of fertilizer will also help flowers recover. Apply ammonium phosphate or a complete flowering plant fertilizer at the rate of 2 lbs. for every 100 square feet of flower bed area. When placing the fertilizer, avoid getting it on the leaves. Watering after application will help wash any fertilizer off the plants and soak it into the ground for a quick response. %0A%0APlants which have been subjected to freeze injury should be watered to keep the soil moist. With the warm conditions that have occurred since early January, plants are susceptible to drying out if adequate watering is not maintained. Water should be done on an as-needed basis. Generally speaking, watering once every two weeks should be sufficient for cold injured trees and shrubs. Depending on the temperatures, flowers and vegetables will need watering 2 or 3 times weekly. %0A%0AFertilization of trees and shrubs damaged by the cold is not recommended at this time of year. Plants are in a period of slowed growth or dormancy in the winter, and do not need fertilization. In the case of cold damaged plants, fertilization is detrimental as it encourages new growth that is even more susceptible to freezing. Wait until the danger of frost has past and the weather has warmed sufficiently to encourage new spring growth before fertilizing. %0A%0AQueen palms are the only cold-sensitive palm commonly grown in Tucson. They need special attention after cold injury. Unlike trees, palms have only one growing point. If it is killed as a result of cold injury, the palm is lost. The problem isn't so much direct cold injury, but the secondary infections that can set in on cold damaged bud tissue. %0A%0AIf some or all of the leaves of your queen palm have turned brown after the recent cold, steps should be taken to protect the bud. First, check to determine if a rot has developed in the crown of the palm. Pull upward on the spear leaf, the newest leaf of the palm which has yet to open. If it easily pulls out and brown discoloration is at the base, rot has set in. %0A%0AThe next step is to treat the bud with a copper fungicide, such as copper hydroxide or Kocide. The product should be mixed according to label directions and sprayed or poured down into the bud. This treatment will control bacterial bud rot, the most common infection resulting from freeze injury. To speed recovery, apply a palm fertilizer in March. This will encourage the bud to grow and produce new leaves.%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on January 26, 1997.%0A%0A|January 26, 1997|
6|27|Care of Newly Planted Trees|It's a great time to plant a tree in your landscape. Cooler autumn temperatures make it less likely that leaves and stems of newly planted trees will shock and dry out. Another advantage is that desert soils are still warm enough in autumn to encourage young roots to grow and establish.%0A%0AWhen purchasing a tree from your favorite local garden center or nursery, make the right choice. Selecting a tree that will eventually outgrow it's allocated space leads to inevitable problems. Look for a tree with a slight taper to the trunk; larger at the bottom and smaller at the top. This is a sign of good trunk development. Also pick one that has branches spaced all along the trunk, even down low. Low branches help increase the girth and strength of the trunk.%0A%0AWhen planting, dig the hole just deep enough to place the top of the root ball flush with the surrounding soil surface. Dig the hole one or two feet wider than the root ball to provide space for new roots to grow. Fill around the tree roots with the soil you dug from the hole, taking care to remove any large rocks.%0A%0ATo help direct water down to the roots and prevent run-off, form an irrigation well around the tree. This is made by mounding up soil up a few inches high in a circle at the outside edge of the tree's root ball. The ring of raised soil will help hold irrigation water until it absorbs into the roots and surrounding soil.%0A%0AAfter planting, make sure the tree is watered often enough to keep the soil moist. Warm weather may necessitate daily watering for the first two or three weeks. As temperatures cool, gradually lengthen the intervals between watering.%0A%0ARegardless of the type of tree you have planted, native desert or non-desert tree, they all need to be watered on a regular basis until they become established. This usually takes one complete growing season. Trees planted this fall, should be fully established by next fall. When established, native desert trees such as palo verde can be taken off irrigation entirely. Introduced tree species such as live oak, however, will require continued watering throughout their life.%0A%0AYoung trees should be mulched after planting. Mulch is a covering placed over the soil. Mulch materials include; decomposed granite, landscape rock, bagged bark or ground wood mulch. The best mulch material is ground wood. It is sold locally as bagged cedar mulch. A three inch layer of cedar mulch placed over the roots, from the trunk to the edge of the branches will help conserve soil moisture and moderate soil temperatures. Another advantage of wood mulch is that it slowly decomposes and as it does, adds organic matter to the soil.%0A%0AWhenever possible, avoid staking trees. Small trees seldom need support. The purpose of staking is to prevent the root ball from moving in the soil and tearing off emerging roots. Our heavy mineral soils are usually sufficient to anchor the root ball. Never stake the tree to prevent the trunk from bending. The natural bending motion of the trunk is beneficial in developing something called "tension strength" in the trunk.%0A%0AWhen staking is absolutely necessary, do it right! Use two stakes only. Wood stakes should be two inches in diameter. These large poles are often referred to as lodge poles. Place them outside the root ball and irrigated area at right angles to the prevailing wind. Make sure poles penetrate undisturbed soil at least six inches.%0A%0ASupport ties are attached from the poles to the tree trunk. Horticultural tape can be used to tie small trees. Tie wires can be used on larger trees. When using tie wires, thread the wire through pieces of garden hose to protect the trunk. The garden hose sections should be long enough to loop around the trunk. The wire can then be twisted at the ends of the hose to keep it in place around the trunk. Don't over-tighten the wire from the trunk to the poles. Leave enough slack in the wire to allow breezes to move the trunk slightly. After one full growing season, support wires and poles should be removed.%0A%0AFinally, wait until Spring to fertilize newly planted trees. In March, just prior to Spring growth apply a small amount of ammonium sulfate (21-0-0) or other fertilizer high in nitrogen. For small trees (5-15 gallon size) apply two to four heaping tablespoons per tree sprinkled over the roots and watered into the soil. For larger trees (24 to 36 inch boxed) apply one-half to one cup of fertilizer per tree sprinkled under the branches and watered in.%0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on September 26, 1999 %0A|September 26, 1999 |
7|26|Caring for Holiday Plants|What would the holidays be without the beauty of seasonal potted flowering plants. Next to the Christmas tree itself, the poinsettia is the plant most identified with the holiday season. Others popular types include the Christmas cactus, kalanchoe, and amaryllis.%0A%0AMost are easy-care plants if you give them the right treatment. Be sure to read the care tag that comes with most pot plants. In addition, here are a few more suggestions for keeping your holiday plants looking good.%0A%0APoinsettias are tropical plants native to Central America, so they like warm temperatures. Their leaves will drop if placed in a cold, drafty spot near doors and windows. They will also drop leaves and red petallike bracts (modified leaves) if they don't get the light and moisture they require. Provide at least 4 hours of direct sunlight, ideally from an east facing window. Keep poinsettias back some from south and west facing windows were it could get too hot.%0A%0APoinsettias dislike fluctuations in soil moisture. Be consistent with your watering. Water thoroughly, but let the soil dry slightly between waterings. If your poinsettia has a decorative foil wrap around the pot, poke holes in the bottom to allow water to drain out.%0A%0AHoliday cactus can refer to either Thanksgiving or Christmas or Easter cactus. Denoted by the season they bloom, these are true cacti from mountain regions of Brazil, rather than the desert. Flowers which can be red, pink, lavender or white, burst forth on the ends of cascading green stems. Stems are broad and flattened, and like other cacti, serve the purpose of leaves.%0A%0AHoliday cactus respond to cool temperatures and shortened days by blooming. Therefore, keep these plants in a cool spot at night. During the day keep them in a bright location, but away from direct sunlight. Keep the soil evenly moist, not wet. Fertilize every 2 weeks with a liquid plant food such as 15-15-15 or similar analysis.%0A%0AKalanchoe have beautiful star shaped flowers in clusters covering the plant. Leaves are succulent, broad and dark green. Traditionally plants have either red or pink flowers, but sometimes can be found with coral or yellow blooms.%0A%0AWith their thick, succulent leaves for water storage, kalanchoe don't need a lot of water. Allow the soil to dry out sufficiently between thorough waterings. Shiny leaves become a dull green when its time to water again. Kalanchoes like full sun, at least 4 hours a day. At night, kalanchoes prefer a cool location. If temperatures are too warm indoors, move the plant to the patio overnight.%0A%0AAmaryllis are spectacular flowering bulbs which bear gigantic trumpet blooms in a wide range and mix of holiday colors. You can find them for sale in florist shops, garden centers and nurseries in bloom or potted, ready to grow and bloom for the holidays.%0A%0AWhen growing amaryllis from the bulb indoors, give it plenty of water and keep it in a warm, sunny location as leaves and flower stalk grow. As soon as the buds develop move it to a spot where it has indirect light. Water regularly, as blooming amaryllis are thirsty! Heat shortens the bloom life, so move blooming amaryllis to a cool location at night.%0A%0AWhen finished blooming, amaryllis may be kept as a house plant for next year's bloom. As flowers fade, cut off the bloom spike, not the leaves. Apply water soluble fertilizer, such as 20- 20-20 or similar analysis every two weeks, for the next 6 months. At the end of the period the plant will go dormant and leaves will yellow. At that time store the bulb, pot and all, in a cool, dark place. Don't water until the following November. Amaryllis can also be planted directly outside in a shady location. The north side of the house is best. Every couple of years divide the bulbs in the fall and replant the largest spacing them out several inches apart.%0A%0ACut flowers and floral centerpieces are also popular around the holidays. To keep them fresh, change the water daily if the flowers are contained in a vase. Cutting off the bottom of the stems from time to time will also maximize water absorption and extend the life of your flowers.%0A%0AIf the arrangement is held in florist foam, water regularly to keep the foam moist. Keep flowers away from ripening fruit! The ethylene gas given off in the ripening process can shorten the life of your cut flowers. Flowers should also be located well away from heat sources; such as the kitchen, fireplace, television, and direct sunlight.%0A%0AFor more information on holiday plant care and other gardening topics call the Pima County Extension Plant Clinics. In Tucson, call 626-5161, weekdays from 9:30 a.m. to 3:30 p.m. or in Green Valley, call 648-0808, Monday, Wednesday, and Friday from 9:30 a.m. to 1:30 p.m.%0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on December 26, 1999 %0A%0A|December 26, 1999 |
8|24|Controlling  Summer Weeds |How do you get rid of summer weeds? Don't give them a chance to grow. Thousands of dormant weed seeds scattered about your landscape, lie in wait for summer rains. Once the rains start the seeds sprout and grow. Applications of weed preventers now, will kill the weed seeds as they germinate. This prevents your landscape from becoming one big weed patch.  %0APre-emergent weed killers are chemicals that work to control weeds before they emerge (begin growing). They lay down a chemical barrier over the soil which either prevents weed seeds from germinating, or kills them shortly after they do. Lots of people don't use pre-emergent weed killers because they can't actually see the benefit of their efforts. Weeds are not there at the time of treatment, and they never show up later. It's much more rewarding to squirt a weed and watch it die a slow and agonizing death. The truth is, it's much more effective to never see them grow in the first place. That's the benefit of pre-emergent weed killers.  %0A%0AWhen shopping for pre-emergent weed killers look for names like Weed Stopper, Weed and Grass Preventer, and Weed Preventer. These are brand names. The actual chemical name is listed on the front label under active ingredients. Although brand names will narrow your search, always purchase on the basis of the products chemical or (trade name). Oryzalin (Surflan) is the chemical and trade name for a weed killer sold under different brand names such as Weed Stopper and Amaze.  %0A%0AOryzalin (Surflan) is one of the better pre-emergent weed killers for use in desert landscapes. It comes in a liquid that is diluted in water and sprayed over bare soil or decomposed granite mulch. Oryzalin (Surflan) does not need to be mechanically mixed with the soil, as do many other pre-emergents. After it is applied, it must be watered into the soil by applying between one half and one inch of water. To do this use a lawn type sprinkler attached to a garden hose. Put cans under the sprinkler to measure the amount of water you are applying. When the cans have filled with one half to one inch of water, your done with that section. Once down, oryzalin will provide control of many types of weeds from 2 to 8 months, depending on the application rate.  %0A%0AOther effective pre-emergents that can be irrigated in after application include; trifluralin (treflan), pendemethalin (pendulum), and prodiamine (Barricade). All these chemicals are related to oryzalin (Surflan), and have similar weed controlling properties.  %0A%0AAlways follow label directions when applying weed killers. To be effective, pre-emergent weed killers must be applied at the recommended rates. They also should be applied as evenly and uniformly as possible. Missed spots or areas were too little is applied will result in poor weed control. Over applied areas can result in damage to surrounding landscape plants. A factor limiting uniformity of application is the garden sprayer. Nozzles are not designed for application to flat surfaces, but rather to leaves of plants. You may wish to have a commercial pest control service or landscape maintenance make the application for you. They have specialized spray equipment and the materials necessary to do a top notch job.  %0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,  520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on June 9, 1996%0A|June 9, 1996|
9|25|Christmas Tree Selection and Care|There's nothing like a real Christmas tree to brighten the holiday season. Be it a fresh cut tree or a living tree growing in a pot, the sight and sent of mother nature's handy work can't be beat!%0A%0AReal Christmas trees are environmentally friendly. Unlike artificial trees, fresh cut trees are completely bio-degradable. Living trees are also available and can be planted after the holidays to enhance our environment. %0A%0AChristmas trees are a renewable resource. For every tree cut, 3 seedling trees are planted in it's place. Often grown on soils that will not support other crops, Christmas trees help to stabilize soil and provide needed refuge for wildlife. Tree farms also protect water supplies, helps clean the air, and provide scenic green belts. %0A%0AChristmas tree tradition dates back to ancient times, when evergreens were used to celebrate the winter solstice, the shortest day of the year, which occurs the 21st of December. The first recorded reference to the Christmas tree dates back to the 16th century in Strasbourg, Germany. There families decorated fir trees with colored paper, fruits and sweets.%0A%0AThe tradition was brought to America in the late 1700's by German settlers and Hessian mercenaries paid to fight in the Revolutionary War.%0A%0AOur modern tradition of tree decoration was begun by a man named Charles Minnegrode in Williamsburg Virginia in 1842. Of course, at that time, trees were adorned with candles, not electric lights.%0A%0AThe most popular fresh-cut Christmas trees sold in Tucson are the Douglas and Noble fir trees. Both are short needled and easy to decorate. Douglas fir has been widely used as Christmas tree since the 1920's. It is a short needled tree with an open, but symmetrical branching structure. The Noble fir, like the Douglas, has short needles but is a denser branched tree and has a propensity for holding it's needles longer after being cut. For these reasons it has become the Christmas tree of choice for many. %0A%0AWhen you purchase a Christmas tree, regardless of the type, make sure it's fresh. Gently grasp a branch with your thumb and forefinger and pull it toward you. Very few needles should come off in your hand. Also take a look at the ground around the tree. You shouldn't see excessive amounts of needles on the ground. Some brown needles in the tree's interior are normal.%0A%0ABefore setting your tree in it's stand, cut an inch or so off the base of the trunk. This fresh-cut will allow water to be absorbed by the trunk, keeping the needles moist. Make sure your tree stand is large enough to hold a gallon of water. At first, Christmas trees will absorb up to one gallon of water daily. %0A%0AAlways keep water in the tree stand. Never allow the level of water to fall below the base of the trunk. If the cut end dries out, it will seal over with resin and not absorb any more water. It's not easy to recut the trunk on a tree loaded with decorations.%0A%0AA lot has been said about the magic elixir, one that will keep you tree fresh forever. All you really need is water. But if you'll still like to try a preservative; here's one you can make at home. Mix one 12 ounce can of a citric acid soft drink, such as 7-up or sprite, and two tablespoon of household bleach in one gallon of water. You can also by commercial preservatives in packets that can be mixed with the water. Most importantly, keep plain water or the preservative mix in the tree stand at all times.%0A%0ALocate your Christmas tree away from heat sources. This includes fireplaces, south and west facing windows, televisions and hot air vents. The cooler the temperatures, the longer your tree will last.%0A%0ALiving trees can also be purchased and used as Christmas trees. Their usually sold in 5 and 10 gallon containers. Like cut trees, they need regular watering. Try not to keep them indoors longer than two weeks. Longer stays indoors can cause significant needle drop.%0A%0AThe living trees most frequently sold in the Tucson area are aleppo and eldaricia pine. Make sure you have plenty of room in your landscape to grow these trees. Both are large evergreen trees, eventually growing 30 feet across and 50 feet high.%0A%0AFinally, when decorating your tree, remember, smaller lights give off less heat. Limiting the size and number of light strings will help keep your tree fresher through the holidays. This is especially important for living trees.%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on November 29, 1998%0A|November 29, 1998|
10|23|El Nino Brings Lots of Weeds|Lots of rain over the last two months has brought with it a bumper crop of weeds. Gardens and landscapes are literally being choked with London rocket, shepard's purse, foxtail and a host of other undesirable species, recently sprouted from seed. %0A%0AIt's too late for pre-emergent weed control, but control is necessary because maturing weeds will soon produce seed for next year's crop of weeds. %0A%0AMechanical control is probably the best method to eliminate weeds know, especially for weeds that have grown large. Many of the weeds growing now are annuals and only come up from seed. Unlike perennials, these annual weeds will not re-grow from the roots. So killing the above ground, leafy portion, of the plant will eradicate the weed. %0A%0ACutting weeds off with a sharp garden hoe is most effective. Simply shave the weeds off at the soil surface. If your careful, powered string trimmers can also be used to cut down weeds. String trimmers should not be used in rock mulched areas however. Gravel and rocks can be dangerously thrown by the flailing string line. %0A%0AHand pulling weeds is effective when weeds are young. Larger, more mature weeds, however will have an extensive root system very difficult to pull out of the soil. And if you do, the roots from nearby desirable plants will be damaged. Also young weeds will pull much easier if the soil is moist. %0A%0APowered tillers, both large and small can be used to cut down weeds in cultivated gardens. A shallow setting of the tines is best. This will cut or shave off the weeds without turning too much soil over and exposing more weed seed. %0A%0AChemical control of weeds may be used in leu of mechanical control measures. Because a majority of weeds growing now are of the annual variety, as with hoeing, only the above ground portion of the weed need be killed. Chemical weed killers that can accomplish this fall into the category of contact or locally systemic herbicides, such as diquat or finale. They can be purchased in liquid form at most garden centers and nurseries. It's important when using either of these products to spray the entire weed. It is most effective to treat actively growing weeds. Don't wait until the weeds get large and mature. At that point, it will be more difficult to kill them. %0A%0AWhen using any chemical, weed killers included, follow all label directions. Mix the concentration of spray recommended. Mixing a stronger, or weaker solution of spray than that recommended will result in poor control. Wear a long sleeve shirt and pants, use chemical resistant gloves, and wear goggles or safety glasses as a minimum. If the label calls for further protective equipment, wear it! %0A%0AWhen spraying weed killers, use only a sprayer designated for that use. Even when sprayers are properly washed, some chemical residue may remain. If you then mix an insecticide in that same tank to spray, lets say, tomatoes for aphids, the tomatoes can be injured. %0A%0ASpray post-emergent herbicides when the air is calm. Early morning is a good time because temperatures are cool and the wind is generally down. Never spray under windy or breezy conditions! Spray may drift onto valuable plants and cause damage. If you must spray weeds close to valuable plants, use a shield made of a large piece or cardboard to place between the weeds and surrounding plants. %0A%0AFinally, to prevent weeds from re-growing, consider using pre-emergent herbicides. Amaze, Surflan XL, and Portait herbicides all come in easy-to-use granular forms. They provide control of weeds for four to six months. To be effective pre-emergent herbicides are best applied prior to rainy periods in the summer and winter. They also must be watered into the top layer of soil. %0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on June 9, 1996%0A|June 9, 1996|
11|22|Grooming Plants Keeps them Healthy|From time to time it's important to do some routine grooming of your plants to keep them healthy and looking their best. Both indoor and outdoor plants will benefit from a little sprucing up in the form of snipping, washing, and in some cases even polishing.%0A%0AThe rigors of desert life take their toll on the many non-desert plants we like to grow. It's common to have summer-damaged leaves and branches that need to be removed to maintain healthy growth. When removing dead stems or branches, always cut back to a healthy dormant bud, side branch, or to the main trunk. Buds are located at the base of leaf attachments on smaller stems of trees and shrubs.%0A%0AMany desert trees such as mesquite and palo verde develop unsightly water sprouts and suckering shoots. These small but vigorous stems grow from either the base of the trunk or from the roots. They sap energy from the tree, energy that should go to the development of the tree's leafy canopy. Prune these off as soon as you notice them growing. In the case of water sprouts arising from the trunk, cut them off flush with the trunk. Suckering shoots arising from the roots should be cut at the soil line. Removing these errant shoots will improve the health and appearance of your trees.%0A%0ACommercial planted trees are often staked to hold them in place. These stakes and the accompanying wires that connect to the trunk should be removed when the tree is established. If the tree has been planted and growing for one season, spring to fall, it is established. Leaving the guying wires on longer can result in damage to the trunk as the tree expands and grows into the wires.%0A%0ALike outdoor plants, house plants also need regular grooming. Older, yellow or brown leaves should be removed on a regular basis. As plants grow and produce new leaves, the older ones die naturally. Although some will fall off, the majority cling to the plant in the absence of exposure to the elements. These spent leaves should be cut off rather than pulled off. Sometimes the base of the spent leaf, on such potted plants as dracaenas, dieffenbachias, and palms will cling so tightly, that pulling it off can damage the stem. Use a sharp pruning shears to cut the leaf off close to where it attaches onto the stem. Eventually, the leaf base itself can be pealed off easily.%0A%0AOn larger-leafed varieties of tropical foliage plants, sometimes just the leaf tips turn brown. This commonly occurs on bamboo palms, draceaenas, spathiphyllum, and philodendron. Low humidity and damage from excess salts are the usual causes. Rather than removing the entire leaf, just the browned tip can be cut away. Use a scissors to snip off the tip, making a pointed cut to repeat the natural form of the leaf.%0A%0AMuch has been made about the benefit, or harm in using plant leaf polishes. As with most things, used in moderation leaf polishes are not harmful to plants. Besides making leaves look shiny and healthy, polishes help repel dust. Keeping the leaves of house plants clean is very important. Dusty leaves block light! This can be especially harmful in areas where plants are receiving only a minimal amount of natural lighting. Periodically, wash plant leaves with clear water or a mild soapy solution to remove dust. Always use tepid or room-temperature water, never hot or cold.%0A%0AFinally, keep a look-out for pest problems, such as spider mites. Because they spin webs, one of the first signs of mites is a dusty appearance to the leaves. Look closely with a magnifying glass. If you see small dots the size of a pin head crawling about, your plants have spider mites! Washing the leaves with a soapy solution, two or three times over a two week period, should control them.%0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on December 19, 1999 %0A%0A|December 19, 1999 |
12|20|How 'Not' to Plant a Tree or Shrub|More trees and shrubs fail because of improper planting than any other single reason. Digging holes too large, setting plants too deep, and adding amendments to the backfill soil all contribute to plant failure. %0A%0AWhen planting trees or shrubs, do not dig an oversized hole! Many people dig the planting hole deeper, often much deeper, than the height of the root ball. This is often done with the mistaken belief that digging a deep hole will encourage deep rooting. It doesn't! Most roots emerge from the top half of the container root ball. As they grow outward, they also gradually grow downward. Eventually two to three feet deep, but rarely deeper. Roots of container grown plants do not grow directly down from the bottom of the pot and they do not develop tap roots. So digging deeper than just deep enough to set the plant into the hole is a waste of time and effort. Worse yet, the loosened soil in the bottom of the hole can cause the plant to sink in the hole. As it does, soil washes over the tree trunk, or main stem in the case of shrubs, causing it to slowly rot. %0A%0AAlways plant so that the top layer of roots are level, or slightly above the surrounding soil. Dig the hole only as deep as the root ball is high. If you dig the hole a little too deep, add some soil to the bottom and compact it until you raise the bottom to the right level. The hole should, however, be dug wider than the root ball. This will provide a loosening of the soil and ease the growth of new roots. It is advised to dig the hole twice as wide as the root ball. %0A%0ADo not mix organic amendments into the soil used to backfill the planting hole. Peat, compost, manure or topsoil mixed with or used as backfill for the hole will inhibit the development of new roots. Worse yet, the hole filled with improved soil acts as a pot in the ground. As roots grow to the edge of this "in-ground" pot, they stop growing out and begin circling around the inside of the hole. With such a small area to grow roots, trees planted in this fashion often blow over in a strong wind. If they don't blow over, they begin a slow decline as roots grow in on themselves and the trunk. %0A%0AThe best soil backfill for the planting hole is that which was dug from the hole. Of course, large rocks should be removed. The soil, and any caliche present should be broken up with a shovel or garden rake to eliminate any large soil clods. The loosened soil can then be filled back in around the roots of the newly planted tree or shrub. With no artificial soil mix present, the roots immediately grow out into the native soil. From there on, they just keep growing, forming an expansive, healthy root system.%0A%0AA troublesome aspect to planting can be caliche. This hard, nearly concrete-like substance underlies the soil in many locations in and around Tucson. The thickness of the caliche and it's proximity to the soil surface varies greatly. Sometimes it is just a few inches below the surface. Other times it may be several feet down, or even non-existent. If present, it can be a solid layer, but more often it is fractured with cracks and crevices that allow water to drain through. %0A%0ARarely is it necessary to dig out the caliche when planting. Unless the caliche is at or just under the soil surface, trees and shrubs can be planted on top of it. By selecting plants in small containers, five or fifteen gallon sizes, the depth of the planting hole can be kept at a minimum. If after digging down to the caliche, not enough room is available to set the root ball all the way in, simply mound up soil around the exposed portion of the roots. Tapering the soil out gradually from the root ball will prevent soil from washing away during heavy summer rains. As the roots grow out they will first grow over the caliche. Then as they find cracks in the caliche, will grow through it.%0A%0ATake special care to avoid the "do-nots" of digging deep holes, setting the plant too deep or adding organic amendments. This applies to non-desert plants like citrus and oleander just as much as it does to desert palo verdes and Texas rangers. All require the same planting methods for success %0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on April 16, 2000%0A%0A|April 19, 2001|
13|19|Iron Deficiencies of Landscape Plants|We grow, or attempt to grow, many plants here in Tucson that are not well suited to our desert environment. Take for instance the beloved gardenia. It's the standout flowering shrub of the Old South. Grown for its fragrant white blossoms set among deep green leaves, this plant loves moist, humid conditions and rich acidic soils. But plant it here in the desert and our dry climate causes flower buds to abort, and alkaline soils turn deep green leaves to a sickly yellow. %0AAt least half of the landscape plants we commonly use do not have their origins in desert locations. Plants like hibiscus, rose, Indian hawthorn, passion flower, citrus, pyracantha and many others prefer acidic soils. Without them leaves turn yellow, most often from a lack of iron. %0A%0AIron deficiencies are typified by yellowing of the young leaves and new growth. There is a defined pattern to this yellowing. The areas between the leaf veins yellow first, while the veins remain green. This presents a herringbone-like pattern. In time, as iron starvation becomes more acute, even the veins turn yellow and the entire leaf can fade to white. Leaves lower down the stems will exhibit less pronounced symptoms. %0A%0AWe do have naturally occurring iron in our desert soils. The problem, however, is that this iron is not in a soluble, or usable, form for plants. Sulfur is often added in the mistaken hope of acidifying the soil. It doesn't work! Our soils are alkaline due to extremely high levels of naturally occurring calcium, particularly calcium carbonate. To neutralize all that calcium would require an unfathomable amount of sulfur! So what's to be done? %0A%0AThe key to correcting common iron deficiencies is to apply iron in a form that is available to plants. Water soluble iron is available for root uptake by plants and is referred to as chelated iron. Garden centers, nurseries, and horticulture supply stores all carry chelated iron products. The most commonly available brands include; Ferion, Ferriplus, and Sequestar. These products come in smaller quantities designed for the home gardener. Other products such as Sprint 138 (Sequestrene) are sold in larger quantities for commercial landscapers and nursery growers. All of these products provide season long correction of iron deficiencies for landscape plants. Container grown plants may require more frequent applications to keep them iron rich. Don't waste money buying non-chelated forms of iron. Although these products may be well known, and inexpensive, the truth is they just don't work in our desert soils! %0A%0AChelated iron products are typically diluted in water and applied to the soil. In addition, iron can be sprayed on the foliage to be absorbed directly into the leaf. When foliar applications are made, a wetting agent or spreader-sticker must be mixed with the iron spray to provide even coating of the leaf surface. Liquid dish washing detergent can be used as a wetting agent. Just add two or three drops to each gallon of spray mix. Chelated iron should be applied during warm weather, when plants are actively growing. Fall and Winter applications are not advised, as cool weather will prevent uptake of the iron. %0A%0AWhen fertilizing plants in general, but more specifically iron deficient plants, use an ammonium-based fertilizer. The ammonium in ammonium sulfate (21-0-0) and ammonium phosphate (16-20-0) have the ability to provide some short-term modification of soil pH which is beneficial for the uptake of iron, as well as phosphorous, manganese, and zinc. %0A%0AFinally, take care to correct nutrient deficiencies, such as iron, in their early stages. The more severe the deficiency, the harder it becomes to correct.  %0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on June 13, 1999 %0A%0A|June 13, 1999 |
14|18|July Is A Good Time to Fertilize Palms|If your palms are looking a little peaked, it could be their not getting the care they need. Although some varieties of palms, such as the "true" date palm (Phoenix dactylifera), and Mexican fan palm (Washingtonia robusta) come from arid regions of the world, they need some special care to flourish here in the Sonoran desert. The reward is a luxuriant tropical appearance that provides a pleasing compliment to equally exotic native species; like the saguaro and octopus agave. %0ADeep water on a regular basis. Even palms adapted to arid regions, such as date palms and Mexican fan palms benefit from watering every two to three weeks during the spring and summer. Other palm species originating in moister regions of the world, such as queen palm (Syagrus romanzoffiana) and pindo palm (Butia capitata) need watering every one to two weeks.  %0A%0AWater deeply, so that the soil is wetted to a depth of two feet. Palm roots will extend out as far as irrigation is provided from the trunk. Water out from the trunk a minimum of four feet. A watering basin can be made by forming a circling ridge of soil several inches high.  %0A%0AFertilize with "palm special" fertilizer. Palms have exacting needs when it comes to nutrients. Scientific research has determined the best ratios of macro and micro nutrients. These are now available in so-called "palm special" fertilizers. Not all such fertilizers are the real thing. Look on the label to make sure the nutrients are in the following proportions: nitrogen (10%25 to 20%25), phosphorous (5%25 to 10%25), potassium (10%25 to 20%25), magnesium (2%25 to 5%25), and (.5%25) of manganese and iron. It should also contain sulfur and trace amounts of zinc and copper. Nitrogen and potassium should be in equal percentages and in a slow release form.  %0A%0ADry, granular fertilizer should be broadcast or banded under the canopy of the palm, or equally distributed around the drip emitters. Never place fertilizer against the trunk. One application in March and another in July should be adequate. For palms under eight feet tall, 2-5 lbs of fertilizer per feeding should be adequate. Newly planted palms can receive even less (½ to 2 lbs depending on the size). Large, mature palms should receive 5 to 8 lbs each application.  %0A%0AIf palms are suffering from nutrient deficiencies, then supplemental amounts of the deficient nutrients will be required. Magnesium deficiencies are common on date palms (Phoenix species). Older leaves turn yellow first, progresssing up to younger leaves. Leaflet tips yellow while the bases remain green. Correction of this deficiency requires the addition of magnesium sulfate to the soil. %0A%0AQueen palms are often deficient in manganese, not to be confused with magnesium. Manganese deficiency on Queen palm causes the new leaves to become yellow or brown and frizzled, which gives this disorder its common name: "frizzle top". New growth is crinkled and distorted. Correction of this deficiency requires the addition of manganese sulfate to the soil, and as a spray on the new growth. Manganese deficiency is also common on sago palm or king sago (Cycas revoluta). Although palm-like in appearance, sago palm actually belongs to a family of prehistoric plants called Cycads.  %0A%0APruning should never be excessive. Hurricane pruning is a common practice along the Atlantic and Gulf Coasts. All but the very top fronds are removed just prior to Hurricane season. Hear in Tucson we have no hurricanes, and yet the practice of hurricane pruning, or "rooster-tailing" is alive and well. This excessive pruning of palms is not recommended. Only yellowing or brown fronds should be removed from palms. Green fronds manufacture the food reserves to provide for new top and root growth. Removing these fronds gradually weakens the palm, slowing its growth and making it more susceptible to insect and disease problems.  %0A%0ASometimes commercial pruning practices dictate the removal of some green fronds, but never should this be excessive. Superimposing an imaginary clock face over the leaf canopy, pruning should never remove those leaves between the 10 o’clock and 2 o'clock positions. %0A%0AIf your pruning your own palms, allow the yellowing leaves to turn brown before removing them. Palms draw the nutrients for the old, yellowing leaves and transfer them to the newer growth. This reduces the chances your palms will become nutrient deficient. %0A%0AFor more information on palms and other gardening topics contact the Pima County Cooperative Extension. Master Gardeners are available from 9:30 a.m. to 3:30 p.m., Monday thru Friday to answer your gardening questions, by phoning 626-5161. %0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on July 19, 1998 %0A%0A|July 19, 1998 |
15|16|Low Light can Cause Plant Problems|Believe it or not, even in Arizona, lack of sunlight can cause plant problems. This can occur in late Autumn and into the Winter, as our days shorten and the sun continues to sink lower into the southern skies. The reduced number of daylight hours and lower sun intensity can cause problems as some sun-loving plants may not receive all the light they need to grow and flower properly.%0A%0AHouse plants are most commonly effected by reductions in light levels. Plants growing in north-facing windows or those in room interiors far away from windows may become light deficient. The first indication may be a yellowing or dropping of leaves throughout the plant. Plants craving light often stretch out for it creating long, spindly growth. Usually compact plants become thin and leggy, developing long spaces between leaves. Flowering plants cease flowering. As conditions worsen, plants become stunted and simply stop growing!%0A%0AIt will be necessary to relocate high light requiring plants such as hibiscus, jade plant, asparagus fern, hoya, schefflera and others. Moving them to east-facing windows, or closer to west and south-facing windows will provide additional light. Be careful not to place plants in locations exposed to strong direct sun-light. This can cause plants to sun-scorch or wilt from excessive heat build-up.%0A%0APlacing house plants near an artificial light source during the evening hours can also be used to increase light exposure. Plants can be placed close to fluorescent lights. However, keep them back a foot or so from incandescent bulbs as they can be damaged by the heat produced by these bulbs. When starting garden seedlings indoors use a combination of one cool white and one warm white fluorescent tube in a single fixture, such as a utility lamp. This combination provides the best reproduction of natural sunlight.%0A%0AJust as plants indoors may not be receiving enough light in north exposures, the same holds true for container plants on north-facing patios. Sun-loving flowering plants such as geranium, petunia, snapdragon, calendula, and stock will have sparse blooms or cease flowering altogether in deep shade. When possible, relocate container plants to areas receiving at least 6 hours of direct sunlight per day. Just moving pots farther out from the house, away from the heavy shade created by north-facing house walls and overhangs will help. Longer periods of brighter indirect light can compensate for the lack of direct sunlight.%0A%0AEvergreen trees casting too much shade on patio plants and winter flower or vegetable beds can be pruned to thin growth and allow more sunlight through. Thinning is the selective removal of stems and branches throughout the tree's canopy. Cuts should always be made at the point were the branch to be removed intersects with another branch or the main trunk. Wait until mid-December to prune! Pruning while temperatures are still warm can stimulate new growth that is cold sensitive and easily damaged by frost and freezing temperatures.%0A%0ADo not prune citrus trees to thin growth! The bark of citrus trees are sensitive to light. Exposing the trunk and branches to strong sunlight can cause the wood to sun scald and die.%0A%0AWhen planting vegetable and flower beds, always locate taller growing plants on the north side so that they do not block sun from lower growing varieties. Some flowers are adapted to shade conditions and will bloom well. They include; pansies, impatiens, begonias, and coleus. Plant these when shade conditions cannot be avoided. Many cool season vegetables also tolerant at least partial shade. They include; lettuce, green onions, leeks, kale, cabbage, carrots, beets, radishes, Swiss chard, and turnips.%0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on November 21, 1999 %0A%0A|November 21, 1999 |
16|15|Monsoon Rains Bring Lots of Weeds|There are few negatives when it comes to the abundance of Monsoon rains we have been experiencing this Summer. One down side, however is the emergence of a bumper crop of weeds. Gardens and landscapes are literally being choked with a host of Summer annual weeds which have sprouted, and continue to sprout with the continuation of rains.%0A%0AWeeds complete with desirable garden and landscape plants for water and nutrients. They also harbor insects and diseases that can spread to surrounding plants. Pollen produced by weeds also greatly contributes to the discomfort experienced by allergy sufferers.%0A%0AIt's too late effective use of preventative weed control, but control is necessary because maturing weeds will soon produce seed for next year's crop of weeds.%0A%0AMechanical control is probably the best method to eliminate weeds know, especially for weeds that have grown large. Many of the weeds growing now are annuals and only come up from seed. Unlike perennials, these annual weeds will not re-grow from the roots. So killing the above ground, leafy portion, of the plant will eradicate the weed.%0A%0ACutting weeds off with a sharp garden hoe is most effective. Simply shave the weeds off at the soil surface. If your careful, powered string trimmers can also be used to cut down weeds. String trimmers should not be used in rock mulched areas however. Gravel and rocks can be dangerously thrown by the flailing string line.%0A%0AHand pulling weeds is effective when weeds are young. Larger, more mature weeds, however will have an extensive root system very difficult to pull out of the soil. And if you do, the roots from nearby desirable plants will be damaged. Also young weeds will pull much easier if the soil is moist.%0A%0AGas or electric powered tillers, both large and small, can be used to cut down weeds in cultivated gardens. A shallow setting of the tines is best. This will cut or shave off the weeds without turning too much soil over and exposing more weed seed.%0A%0AChemical control of weeds may be used in lieu of mechanical control measures. Because a majority of weeds growing now are of the annual variety, as with hoeing, only the above ground portion of the weed need be killed. Chemical weed killers that can accomplish this fall into the category of contact or locally systemic herbicides, such as Diquat or Finale. The systemic herbicide "Glyphosate" sold under the trade name "Roundup" may also be used. These products can be purchased at most garden centers and nurseries. It's important when using either of these products to spray the entire weed. It is most effective to treat actively growing weeds. Don't wait until the weeds get large and mature. At that point, it will be more difficult to kill them.%0A%0AWhen using any chemical, weed killers included, follow all label directions. Mix the concentration of spray recommended. Mixing a stronger, or weaker solution of spray than that recommended will result in poor control. Wear a long sleeve shirt and pants, use chemical resistant gloves, and wear goggles or safety glasses as a minimum. If the label calls for further protective equipment, wear it!%0A%0AWhen spraying weed killers, use only a sprayer designated for that use. Even when sprayers are properly washed, some chemical residue may remain. If you then mix an insecticide in that same tank to spray, lets say, tomatoes for aphids, the tomatoes can be injured.%0A%0ASpray post-emergent herbicides when the air is calm. Early morning is a good time because temperatures are cool and the wind is generally down. Never spray under windy or breezy conditions! Spray may drift onto valuable plants and cause damage. If you must spray weeds close to valuable plants, use a shield made of a large piece or cardboard to place between the weeds and surrounding plants.%0A%0AFinally, to prevent weeds from re-growing, consider using pre-emergent herbicides. Amaze, Surflan XL, and Portait herbicides all come in easy-to-use granular forms. They provide control of weeds for four to six months. To be effective pre-emergent herbicides are best applied prior to rainy periods in the summer and winter. They also must be watered into the top layer of soil.%0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on August 15, 1999 %0A%0A|August 15, 1999 |
17|14|Most Common Plant Problems|Hundreds of plant samples are brought into the Pima County Extension Plant Clinic each year. Most are samples from dead or dying plants of various species. In all these samples there are some causes of plant failure that seem most prevalent.%0A%0AProbably the single most common cause of plant failure is planting too deep. Trees, shrubs, flowers or vegetables all can succumb from being planted too deep. In the case of small herbaceous plants, death occurs rapidly. Stems covered with soil are attacked by soil inhabiting disease organisms. Stem and root rots develop, and the plant quickly wilts. Digging around the base of the plant will reveal a shriveled, sometimes black or brown stem.%0A%0AWhen trees, shrubs, and other woody stemmed plants are planted too deep, death is gradual. It may take several years for trees to die from the effects of planting too deep. Smaller shrubs and perennial flowers and ground covers will usually succumb within a year of planting.%0A%0APlants should be placed in the ground so that the top set of roots, out of the container or box, are set level or slightly above the surrounding soil surface. Small flower and vegetable transplants should be set in with the top of the soil ball level with the surrounding soil surface.%0A%0AIf you suspect a plant was planted too deep, dig down around the main trunk until you come to the first set of roots. If you must dig down more than an inch or two to find roots, the plant is too deep. Soil should be raked back away from the trunk. This will help prevent the trunk wood from dying, but will not help the roots farther out that may be covered with soil. If you rake the soil back, construct a barrier to keep this soil from washing back in around the plant. You can use landscape edging, or berm the soil up as you would when creating a watering basin.%0A%0APoor soils are another common cause of plant failure. This is especially true of herbaceous plants such as flowers and vegetables. Their fragile roots have real problems growing out into our hard, gravelly soils. The best way to improve desert soils for garden planting is to add lots of organic matter. Compost, aged manure, and peat moss are all good choices to mix into the soil. These organic matters will loosen the soil, making it easier for tender roots to grow in.%0A%0AOrganic matter should be mixed evenly into the soil prior to planting beds of flowers, vegetables or herbs. Incorporate as much as possible, but at minimum put down a layer of 4 inches of organic matter to mix into the top foot of soil. Do not use wood products such as forest mulch, chunk bark or ground wood mulch as organic amendments. These materials are not decomposed and will rob nitrogen from the soil, thus depriving plants of needed nutrients.%0A%0AWhen desert soils are just too difficult to work in, consider container or raised bed gardens. Pots and frame structures for raised beds can be filled with quality potting soil, compost, or bagged top soil.%0A%0AAs could be expected one of the most common reasons for plant failure here in the desert is incorrect watering. During the cool weather of late autumn and winter over-watering is the culprit. As temperatures cool, many gardeners forget to reduce their watering. Plants that are irrigated at the same frequency they were in the summer are subject to root and stem rots. If you were watering say, twice weekly during the summer, then a single watering every week or two should be adequate during the winter months.%0A%0AWhen spring arrives and temperature climb, the frequency of watering must once again be increased. But regardless of the season or frequency of application, it is critical to apply enough water when you do. Irrigate to wet the soil to the proper depth. Trees, should be watered long enough to wet the top two to three feet of soil. For shrubs, wet the soil down 18 inches or so. And for shallow-rooted flowers and vegetables one foot deep wetting is sufficient.%0A%0ATo determine the depth of wetting, after irrigation, push a soil probe (metal rod) down into the soil. The probe will push down through wet soil but will stop when it hits dry soil. If water isn't getting down deep enough, increase the length of time your watering.%0A%0AFinally, when selecting plants, remember to choose desert adapted plants. They can tolerate wide swings in temperature, intense heat and sun, drought, low humidity, drying winds, alkaline soils, high salts, and desert critters. Plants not adapted to the desert struggle and often fail.%0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on November 14, 1999 %0A%0A|November 14, 1999|
18|13|Palms Need Special Care|If your palms are looking a little peaked, it could be their not getting the care they need. Although some varieties of palms, such as the "true" date palm (Phoenix dactylifera), and Mexican fan palm (Washingtonia robusta) come from arid regions of the world, they need some special care to flourish here in the Sonoran desert. The reward is a luxuriant tropical appearance that provides a pleasing compliment to equally exotic native species; like the saguaro and octopus agave. %0A%0ADeep water on a regular basis. Even palms adapted to arid regions, such as date palms and Mexican fan palms benefit from watering every two to three weeks during the spring and summer. Other palm species originating in moister regions of the world, such as queen palm (Syagrus romanzoffiana) and pindo palm (Butia capitata) need watering every one to two weeks. %0A%0AWater deeply, so that the soil is wetted to a depth of two feet. Palm roots will extend out as far as irrigation is provided from the trunk. Water out from the trunk a minimum of four feet. A watering basin can be made by forming a circling ridge of soil several inches high. %0A%0AFertilize with "palm special" fertilizer. Palms have exacting needs when it comes to nutrients. Scientific research has determined the best ratios of macro and micro nutrients. These are now available in so-called "palm special" fertilizers. Not all such fertilizers are the real thing. Look on the label to make sure the nutrients are in the following proportions: nitrogen (10%25 to 20%25), phosphorous (5%25 to 10%25), potassium (10%25 to 20%25), magnesium (2%25 to 5%25), and (.5%25) of manganese and iron. It should also contain sulfur and trace amounts of zinc and copper. Nitrogen and potassium should be in equal percentages and in a slow release form. %0A%0ADry, granular fertilizer should be broadcast or banded under the canopy of the palm, or equally distributed around the drip emitters. Never place fertilizer against the trunk. One application in March and another in June or early July should be adequate. For palms under eight feet tall, 2-5 lbs of fertilizer per feeding should be adequate. Newly planted palms can receive even less (2 to 2 lbs depending on the size). Large, mature palms should receive 5 to 8 lbs each application. %0A%0AIf palms are suffering from nutrient deficiencies, then supplemental amounts of the deficient nutrients will be required. Magnesium deficiencies are common on date palms (Phoenix species). Older leaves turn yellow first, progresssing up to younger leaves. Leaflet tips yellow while the bases remain green. Correction of this deficiency requires the addition of magnesium sulfate to the soil. %0A%0AQueen palms are often deficient in manganese, not to be confused with magnesium. Manganese deficiency on Queen palm causes the new leaves to become yellow or brown and frizzled, which gives this disorder it's common name: "frizzle top". New growth is crinkled and distorted. Correction of this deficiency requires the addition of manganese sulfate to the soil, and as a spray on the new growth. Manganese deficiency is also common on sago palm or king sago (Cycas revoluta). Although palm-like in appearance, sago palm actually belongs to a family of prehistoric plants called Cycads. %0A%0APruning should never be excessive. Hurricane pruning is a common practice along the Atlantic and Gulf Coasts. All but the very top fronds are removed just prior to Hurricane season. Hear in Tucson we have no hurricanes, and yet the practice of hurricane pruning, or "rooster-tailing" is alive and well. This excessive pruning of palms is not recommended. Only yellowing or brown fronds should be removed from palms. Green fronds manufacture the food reserves to provide for new top and root growth. Removing these fronds gradually weakens the palm, slowing it's growth and making it more susceptible to insect and disease problems. %0A%0ASometimes commercial pruning practices dictate the removal of some green fronds, but never should this be excessive. Superimposing an imaginary clock face over the leaf canopy, pruning should never remove those leaves between the 10 o'clock and 2 o'clock positions. %0A%0AIf your pruning your own palms, allow the yellowing leaves to turn brown before removing them. Palms draw the nutrients for the old, yellowing leaves and transfer them to the newer growth. This reduces the chances your palms will become nutrient deficient.%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on June 30, 1996%0A|June 30, 1996|
19|12|Protecting Plants from Winter's Chill|The first killing frost here in Tucson usually occurs during the week of Thanksgiving. While temperatures are still relatively warm, make preparations to protect your cold sensitive plants. %0ACold protection can help extend the life of some warm season garden plants. Covering tomatoes a night or two can provide you with a few more weeks of vine ripened tomatoes. You can also pick green mature tomatoes to ripen up inside. Just make sure the tomatoes you pick have either a pink blush, or a white star on the bottom. %0A%0AMost of our winter flowers and vegetables are cold hardy, to a degree! A light frost is likely only to damage begonias and impatiens. Geraniums are almost as sensitive. Then comes calendula, lobelia, alyssum, and snaps which tolerate temperatures down to 28 degrees. The cold hardiest are petunia, stock, and of course, pansy. Protection for these are needed only when temperatures dip below 20 degrees. Here at the Extension Center temperatures dipped to 17 degrees twice last winter. Admittedly, our location along the Rillito River is one of the coldest around town, but many low areas, along the Rivers and Washes, can experience the same. %0A%0ALeafy winter veggies, including broccoli and cauliflower, have no problem with cold down to the upper teens. Beets were the only crop we experienced injury on at those temperatures. %0A%0AMany tropical types of landscape plants are injured with freezing temperatures. Some of those most commonly planted around Tucson include: bougainvillea, hibiscus, tropical bird-of-paradise, cape honeysuckle, and philodendron. %0A%0APlants in pots are easily moved to warm locations during the winter or on cold nights. South facing walls provide a degree of protection. The warmth of the sun is stored in the masonry wall during the day, and released at night. This can provide several additional degrees of warmth overnight. Placing plants under patio roofs or building overhangs can also provide protection. Warmth radiating up from the ground is trapped by overhead structures. Even placing plants under the canopy of a dense tree or shrub can offer some protection. %0A%0AOur bright Arizona sun is an ally when it comes to cold protecting plants. During the day, the sun's energy is trapped and stored in paving materials, masonry walls, surface mulches, and the soil itself. At night this energy is released around plants, keeping them warmer. %0A%0AMoist soil stores more heat than dry soil. Early in the morning before a predicted freeze, thoroughly wet the soil around plants. By doing so, the soil stores up the sun's energy over the entire day, maximizing the warmth to be released at night.  %0A%0ACoverings placed over plants help to hold in radiant heat released from the soil, and from the plants themselves. These coverings can be cloth sheets, blankets, several sheets of newspaper, paper grocery sacks, or black plastic. The thicker the black plastic, the better it will resist tearing in the wind. Specially made frost blankets, made from spun polyester, can also be purchased from garden suppliers.  %0A%0ARegardless of the covering, it is preferred they not contact plant leaves and flowers, especially black plastic. Cold damage can occur to the parts of the plant in contact with the covering. Make sure that the cover extends to the ground, and it tacked down to prevent lifting from wind or loss of escaping radiated heat. %0A%0AOn very cold nights, a heat source can be placed under the frost covering. For smaller areas, a low wattage incandescent light bulb (40 to 60 watts) can be used. If you are protecting larger areas, such as coverings over tender shrubs or small fruit trees a heat lamp will be more effective. Christmas lights, especially the small twinkle light variety, should not be used as they give off very little heat. %0A%0AWhen the sun rises and temperatures warm above freezing, covers should be removed. Even if a freeze is predicted on consecutive days, removing the cover will allow the sun’s warmth to once again heat the soil and provide a source of radiant heat. %0A%0AFinally, make sure plants are going into the Winter season healthy. Stressed plants are prone to cold injury. Nutrient levels should be adequate to keep plants green, but not too high to push excessive growth. Hold off fertilizing landscape plants and fruit trees until March, when temperatures begin to warm. %0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on November 15, 1998%0A|November 15, 1998|
20|11|Protecting Your Plants From The Cold|The pleasant chill of autumn has returned to Tucson. It reminds us that the cold of Winter can't be far behind. And while were nestled snug in our homes, our garden and landscape plants must endure the frosty weather, come what may. %0AMost of our landscape trees and shrubs are cold adapted. With the exception of some tender introduced species like bougainvillea and hibiscus, desert plants can take the cold. This is not the case, however, for tender vegetables and flowers.  %0A%0AWarm season vegetables like tomatoes and peppers will freeze at 32 degrees. Cool season vegetables like broccoli, lettuce and cauliflower can take slightly colder temperatures. But even they need protection when temperatures dip much below 30 degrees.  %0A%0AFlowers also have varying degrees of cold hardiness. Snapdragons and violas are the most cold hardy. They can tolerate temperatures in the upper teens and low 20 degree range. Petunias and calendulas are slightly less cold tolerant, withstanding temps from the low to mid 20s. Others, such as geraniums and begonias will be damaged with the slightest frost. %0A%0AWhen in doubt about a vegetable or flower plant's cold hardiness, error on the side of caution. If a frost or freeze is forecast, take precautions to protect your plants. Like water, cold air drains down hill. It settles in low areas or pockets. These low areas could be at the bottom of washes and river beds, or in low spots around your home. Anything that restricts the downward movement of cold air, such as walls or fences, also traps cold air. These locations will be the coldest around your home, and the areas were plants are most likely to suffer freeze damage.  %0A%0AAreas exposed to direct winter winds from the North and Northwest will also be vulnerable to cold damage. South facing walls will provide the warmest location. Here plants are protected form winter winds and are exposed to the heating rays of the sun. %0A%0AOur clear winter days here in Arizona give us a winter's edge for fighting cold. Radiation heating from the sun works to warm up sun exposed surfaces. Masonry walls, driveways and walks all absorb the heat of the sun during the day, and release that heat at night. The soil also absorbs heat from sunlight. The radiation, or release of this stored heat helps to moderate night-time temperatures, especially close to the ground where tender plants grow. %0A%0AMoist soil does an even better job of storing the sun's energy. That's why one of the best ways to protect your plants from cold is to thoroughly water the garden soil the morning prior to a predicted frost or freeze. The sun will heat up the moist soil, storing it for release at night. %0A%0ACoverings placed over plants help to hold in radiant heat released from the soil, and from the plants themselves. These coverings can be cloth sheets, blankets, newspaper several sheets thick, or black plastic. The thicker the black plastic, the better it will resist tearing in the wind. Specially made frost blankets, made from spun polyester, can also be purchased from garden suppliers. %0A%0ARegardless of the covering, it is preferred they not contact plant leaves and flowers, especially black plastic. Cold damage can occur to the parts of the plant in contact with the covering. Make sure that the cover extends to the ground, and it tacked down to prevent lifting from wind or loss of escaping radiated heat. %0A%0AOn very cold nights, a heat source can be placed under the frost covering. For smaller areas, a low wattage incandescent light bulb (40 to 60 watts) can be used. If you are protecting larger areas, such as coverings over tender shrubs or small fruit trees a heat lamp will be more effective. %0A%0AWhen the sun rises and temperatures warm above freezing, covers should be removed. Even if a freeze is predicted on consecutive days, removing the cover will allow the sun's warmth to once again heat the soil and provide a source of radiant heat. %0A%0AFinally, make sure plants are going into the Winter season healthy. Stressed plants are prone to cold injury. Nutrient levels should be adequate to keep plants green, but not enough to encourage growth. New growth coming out now is more susceptible to freezing. Hold off fertilizing plants until March, when temperatures begin to warm. %0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on November 17,1996  %0A%0A|November 17,1996  |
22|7|Pruning Shrubs |Pruning is both an art and a science. It can improve the health of plants, and, if done properly, it can also improve their appearance. %0AA properly pruned shrub is a work of art and beauty and does not look as if it has been pruned. Pruning cuts should not be visible but located inside the plant where they will be covered by remaining foliage.  %0A%0AThe first step in pruning a shrub is to remove all dead, diseased or injured branches. Remove branches that cross or touch each other and those that look out of place. If the shrub is still too dense or large, remove some of the oldest branches. This can be done by pruning techniques called heading back, and thinning. Do not use hedge shears. %0A%0AHeading back is a process of cutting back excessively long branches to a bud or lateral branch that is 6 to 12 inches below the desirable plant height. Buds are located at a point on the stem where old leaves were attached. They appear as a swollen bump on the stem. Cut 1/4 inch above a healthy bud or side branch. Make the cut on a slight slant. %0A%0APinching is a type of heading back of young shoots. You can use your thumb and forefinger to remove the stem tips of new growth. Pinching the tip of shoots and branches encourages side branching. Pinching helps keep shrubs bushy, and compact.  %0A%0ATo provide a more natural form, branches should be cut back to varying heights. This random heading back of branches will encourage new growth throughout the shrub. Pruning cuts also tend to be concealed using this method of pruning. Your plants will look great without ever being able to tell they've had a haircut. %0A%0AThinning is the complete removal of branches back to a lateral branch or to the main trunk or to the ground. Depending on how the plant is thinned, thinning can give a plant an open appearance or can encourage new growth inside the crown. If thinning is heavy, interior sprouts will develop. Shrubs are thinned primarily to control size while maintaining a natural appearance. This technique differs from hedging or heading to the same spot on all branches, which will give a shrub a formal, controlled appearance. %0A%0ARejuvenation is a drastic method of pruning old shrubs that have become much too large or have a large amount of non flowering wood. On single stem shrubs, rejuvenation is carried out over a period of three years by severe thinning out to the basic limb frame work. Multiple stem shrubs are rejuvenated by cutting back all the stems near ground level over a period of three years. Remove 1/3 of the old, mature stems the first year. The second year remove oneself of the remaining old stems. Prune back long shoots from the previous year's growth. The third season remove the remaining old wood and head back the long new shoots. The best time for rejuvenation pruning is late winter or early spring.  %0A%0ABasic tools used in pruning are hand shears, loppers, and hand saws. Hand shears are used for general cleanup, loppers for branches up to 11/2 inches in diameter, and pruning saws for larger branches. Both shears and saws are available on poles which are handy to prune difficult to reach branches. %0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-616-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on February 21, 1999 %0A%0A|April 19, 2001|
23|6|Roses Need Attention Now|If large, dark, leafy-green rose bushes loaded with blooms are what your after, now is the time to act! The cooler weather of Fall provides ideal growing conditions for roses. But they also need help to grow and bloom to there maximum potential. This help is in the form of pruning and fertilizing.%0A%0APruning is essential to promote new growth. Only on this new growth will flowers be produced. Light pruning will produce the desired results. Select stems pencil-sized or larger and cut them back to an outward facing leaf. Hidden at the base of the leaf is the dormant bud. Pruning just above this dormant bud will cause it to break (grow) and produce a bloom or spray. To keep the rose bush open to sun and air, prune just above outward-facing buds to encouraged outward-facing growth. Inward-facing growth results in clogging and crossing of branches. Cut about one-quarter inch above the outward facing buds. Make the cut a slanting one, with the bud on the high side.%0A%0ACut back lightly, to produce abundant roses for garden display. Every cut should result in the production of a bloom. Don't cut too far down the stem. You should remove no more than the outer one-third of the stem. Remove stem portions with Summer-scorched leaves. Also remove dead wood, weak and crossing stems. Heavy pruning will not be necessary until January.%0A%0AIf exhibition blooms are what you desire, look for a cane one-half inch thick or go down the length of the cane until it reaches this size. Again, cut on an angle one-quarter inch above an outward facing leaf. These large cuts should be sealed with Elmer's or another type of carpenter's glue to prevent cane boring insects. On exhibition roses it may be necessary to stake the new stem growth to keep it straight.%0A%0ALots of rain this summer has washed nutrients right out of the soil, especially nitrogen. As a result roses appear yellow and anemic. They also may be lacking in iron. To correct these deficiencies apply ammonium a rose fertilizer or any balanced fertilizer containing like amounts of nitrogen, phosphorous, and potassium such as 15-15-15 or similar analysis. One pound of fertilizer per 100 square feet of rose bed area should be adequate. Scratch it in to the top layer of soil and water it in.%0A%0AIf young leaves are yellow with green veins, an iron deficiency is present. To correct this deficiency apply chelated iron according to label directions. Chelated iron should diluted in water and soaked into the soil. For quicker results chelated iron may also be sprayed on leaves for a rapid green-up. Use only chelated forms of iron as they are the only types that will preform in our alkaline desert soils.%0A%0ARoses also benefit from the addition of magnesium. This can be supplied in the form of Epsom salts, applied at the rate of 1/3 cup per rose bush and watered in. Magnesium sulfate, the other name for Epsom salts, is also available in Garden Centers and Nurseries.%0A%0AInsect pests such as aphids may reappear on roses in October. Keep a look out for these small, soft-bodied green bugs. They are attracted to new growth, and their sucking habit of feeding curls young leaves and causes a sticky substance, called honeydew, to develop. Aphids can be controlled by spraying the leaves with a strong jet of water from a hose-end attachment. Soap sprays are also effective at controlling aphids.%0A%0AFinally, reduce the frequency of irrigation as we go later into Fall and the temperatures continue to cool. Typical Autumn temperatures between 65 and 90 degrees will call for twice weekly waterings. Over watering in late Fall and Winter can leach out nutrients and encourage root rot fungus diseases.%0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on October 03, 1999 %0A%0A|October 03, 1999 |
24|2|The "Should Nots" of Pruning|Winter is the best time to prune most trees and shrubs. When plants are dormant, removing twigs, stems and branches can be done without shock to the plant. Also, when done correctly, pruning can promote healthy spring growth. %0A%0AUsually, I discuss proper pruning techniques in my column. However, it may be more beneficial to discuss incorrect ways of pruning. Knowing how not to prune often is often the more logical prerequisite in knowing how to prune! %0A%0AIn the case of palms, I see many trees around town that are being damaged by excessive pruning. Palms should never be pruned to look like "rooster tails". Palms with only the top three or four fronds remaining have been pruned excessively and improperly. Only the lower leaves, the ones which have turned brown or are yellowing should be removed. Correct pruning of palms is a "once a year" job, which is no more often than "rooster-tail" pruning. The difference is that correct pruning keeps palms healthy, and looking their best. If your tree trimmer is "rooster-tailing", just say no! %0A%0ATrees are also excessively pruned. In it's various forms, all excessive pruning is bad. But probably the most common form of abuse is what I call "limbing-up". This involves the removal of lower branches often for no apparent reason. In fact, on many trees, the entire lower half or even two-thirds of the branches are removed. Also referred to as "skirting", this practice removes important food producing limbs, and in the process weakens the trunk and roots, causes excessive wounding, and permanently disfigures the tree. %0A%0AOnce branches are removed, they can never be replaced, and they will not regrow! Most desert trees are naturally low branched and multiple-trunked. Forcing a palo verde or desert willow to look like a tall, single-trunked sugar maple from "back home" just doesn't work. Only remove lower branches if they are dead or dying, an obstruction, or safety concern. Branching does not have to be even all the way around a tree. If you must remove a lower limb on one side of the tree, do not try to balance it by removing limbs on the other side. Limit your branch removal to only what is absolutely necessary. %0A%0AJust as "limbing-up" is the wrong way to prune, so to is "limbing-back". This is when large limbs are arbitrarily cut back. Large stubs remain after this form of severe pruning. In time, these branch stubs will rot, and the decay will move into the main trunk. As the decay progresses, the tree becomes structurally unsound and in danger of falling in a wind storm. Cutting large branches should only be done by a certified arborist who knows the correct procedures of "drop-crotch" pruning. This method, used for thinning and height reduction, does not leave stubs and other large open wounds. %0A%0AWhen it comes to pruning shrubs, throw away the hedge shears! Shaping shrubs like Texas ranger and desert cassia into round balls destroys their shape and blooming potential. More importantly, shearing causes the lower part of the shrub to become bare and twiggy. Eventually only the top of the plant is crowned with leaves. Only rows of formal hedges should be sheared, not individual shrubs. If shrubs need to be pruned for size control, then selective cuting back and removal of the longer branches is advised. Removing them will maintain or reduce the size of the shrub while preserving it's natural form. %0A%0AFinally, if your in doubt about whether or not to prune a tree or shrub, then you probably shouldn't. Use the time you would have spent on unnecessary pruning and have some fun looking through this year's spring gardening catalogs. %0A%0AIf you want to learn more about the correct pruning of desert plants, I highly recommend "Pruning, Planting & Care", by Eric A. Johnson. It is a guide to pruning plants of the Arid West, with lots of color photography and step by step instructions. It can be purchased at many local book stores. %0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on January 30, 2000%0A%0A|April 19, 2001|
26|4|Severe Pruning Injures Trees|Severe pruning of any kind on trees is not recommended.  I would term severe pruning to be the removal of more than one quarter of the tree canopy, the leafy part, at any given time.%0A%0ASevere pruning is usually done under the mistaken belief that it will reduce or control the size of the tree.  Nothing could be further from the truth!   Severe pruning actually stimulates excessive regrowth.  Within a year or two of pruning, trees will actually be larger than they were before pruning.  %0A%0AThe new growth that arises from severe pruning is weak, wound-response growth called water sprouts.  These shoots can grow six to twelve feet in length.  Unlike permanent branches, water sprouts are whips or unbranched shoots.  They often grow so thick as to resemble an upside-down  broom.  Because of their weak attachment to the tree, a strong wind will easily cause these sprouts to break off causing further injury to the tree. %0A%0ASevere pruning is most often done by cutting back the top of the tree, often by as much as 50 percent.  This type of pruning is referred to as topping, hat-racking or rounding over.  In this process, no thought is given as to where to cut back on branches to maintain the health of the tree.  Rather, all branches are cut at the same point out from the trunk.  This leaves large wounds that will not heal properly.  Over time, rot will invade these open wounds and move into the largest limbs and even the trunk.  When the core wood of the branches and trunk become rotted, the entire tree is weakened and more prone to storm damage.%0A%0AEven moderate pruning of trees can be damaging during the Summer, due to a condition called sunburn.  Trimming allows direct sunlight to penetrate the normally shaded interior of the tree.  Thise light-sensitive branches easily become sunburnt, causing the top portion of the branch to die.  As a result, the leaves on these branches will fall off, causing even more light exposure and sunburning.  Citrus trees are extremely sensitive to sunburn, but even desert trees such as mesquite can be damaged in this fashion.%0A%0AIt is important to remember that reducing the leafy top of a tree also reduces the tree's food supply.  It is the leaves which manufacture food for the tree through a process called photosynthesis.   Severe pruning puts the tree in a starvation mode and the burning of stored food reserves.  If starvation is prolonged the tree is likely to become so weakened it will die.%0A%0A%0A%0ATo keep trees healthy, only prune if necessary and then only prune what is needed.  Never prune off more than one quarter to the tree's canopy.  If a branch must be shortened, it should be cut back to a lateral or side-branch large enough to continue healthy growth.  A good rule of thumb is to cut back to a side branch that is at least one third the diameter of the limb being removed.  This technique of pruning will decrease the likelihood of water sprouts developing and will help preserve the natural appearance of the tree.  %0A%0AFinally, I recommend any pruning that requires using a ladder or climbing into the tree be done by a skilled, certified arborist.  This work is too dangerous for the novice.  Professional arborists can determine what type of pruning, if any, will be necessary for your tree.  Choose an arborist that has completed a certification program on tree pruning, such as that conducted by the International Society of Arboriculture.   And don't hesitate to ask for, and check, a list of references.%0A%0A %0A %0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on July 16, 2000%0A|April 19, 2001|
27|17|Landscape Inside During Hot Weather|The oppressive heat of summer makes it difficult to go outside and garden for more than an hour or so, even in the early morning.  So with that in mind, why not spend some cool time indoors planning fall improvements to your landscape.%0A%0AThere are never enough trees.  Think about where you could add a tree or two to your landscape.  The coming fall season is a great time to plant almost anything, including trees.   For shading, the best location is to place a tree on the southwest corner of the house.  Sun and heat are most intense from mid-day to late afternoon.  Blocking the sun from the southwest provides maximum cooling benefits.  Some of the best varieties of shade trees for Tucson include; Arizona ash, desert willow, sweet acacia, willow acacia, blue palo verde, and velvet mesquite.%0A%0ACooling shade can also come from shrubs.  They are effective at blocking sun from the lower half of house walls, areas that trees can't shade.  East and West facing walls should be planted with shrubs that have dense growth.  South facing walls can also be shaded, although summer sun is so nearly overhead that it is mostly blocked from roof overhangs.  Some great shrubs to consider include; dwarf oleander, desert cassia, Greek myrtle, blue Texas ranger, jojoba, and wolly butterfly bush.%0A%0AIf your stuck for space with a narrow side-yard you can choose plants to espalier along the house wall.  Espalier is simply a method of growing plants nearly flat against a wall or fence.  Shoots and branches growing out from the wall are just kept pruned off, while those growing down the wall are encouraged to grow.  Some of the best shrubs to espalier include; pyracantha, photinia, podocarpus, and Japanese privet. %0A%0ATrees that work well in narrow spaces include; shoestring acacia, Japanese yew, and willow pittosporum.  Palms can throw out a surprisingly large amount of shade.  Although they grow to be tall, they can provide shading for the roof.  A good choice would be the desert fan palm because of it's rapid growth rate.  Groupings of palms work best for providing larger areas of shade.%0A%0AAnother prime spot for trees and shrubs to shade is the compressor on your air conditioner.  Plants used to shade will take a lode off the air conditioning and save you money.  Be sure to keep plants back and away from the unit for three feet, so as not to disturb the air flow through the unit. %0A%0A%0A%0AThe more plants in your yard, the more cooling effect you can obtain.  Shading of the ground around the home helps keep temperatures down.  This is especially true if your landscape is mulched with rock.   Rock heats up in the sun and releases the heat very slowly, keeping the area around your home hotter at night.  Shading the rock will prevent it from heating up.  %0A%0APlants also have a natural cooling mechanism called transpiration.  It's the same basic principle as that used in our evaporative coolers at home.  Water is taken in by plant roots and expelled through pores in the leaves.   The evaporation of this water causes a cooling effect not only of the plant, but also the surrounding air.   Thus the more plants, the cooler the environment around your home!   Lawns provide a great cooling effect, but if you don't want the higher water use consider desert adapted ground covers.  They are great for shading the soil and providing evaporative cooling.  Some that I would recommend include; trailing lantana, verbena, ground morning glory, trailing rosemary, calylophus, and trailing indigo bush.%0A%0AFinally, remember that given the proper care, plants grow rapidly, especially shrubs and ground covers.  If you buy smaller plants you can purchase more of them for greater shading, cooling and visual impact.%0A %0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on August 13, 2000%0A|April 19, 2001|
28|5|Salvage Leggy House Plants with Air-layering|Some house plants have a natural tendency to become tall and leggy over time.  This is particularly true of dumb cane, croton, rubber plant, and dracaena.  In fact any houseplant that has a main central stem can, overtime, loose most or all of it's lower leaves.  But there is a way to rehabilitate these plants.  It's called air-layering.%0A%0AAir-layering is a process by which roots are stimulated to grow from a part of the stem. In the case of house plants who have no lower leaves, its a way to make a new plant.  By rooting the stem just below the existing upper leaves, the leafy top can be cut off with the new roots and planted.  You then have a new plant full of leaves from top to bottom!  %0A%0AAir-layering is effective on woody-stemmed plants that are very difficult to root from a cuttings alone.  Because the plant is still partially attached to it's roots during the layering process, water and nutrients continue to be provided to the leaves.    %0A%0AThe first step in the process is to gather your materials.  You'll need a small bag of spaghnum peat moss, a sharp knife, a wooden tooth pick, and some plastic wrap or aluminum foil.  You'll also need a package of rooting hormone to stimulate the roots to grow.  Rooting hormone powder, such as Rootone can be purchased at most places garden supplies are sold.%0A%0AChoose a location on the stem 3 or 4 inches below the lower leaves.  You can also use the air-layering method to reduce the height of a plant.  Just decide how tall you want your plant to be, and at that point on the stem remove the leaves several inches above and below.%0A%0ANext, you are going to wound the stem by cutting through the outer bark and through the cambium layer.  The cambium is a thin layer just below the bark that is responsible for transporting water and nutrients up from the roots and manufactured food in the form of carbohydrates to the roots.%0A%0AThere are two cutting methods.  In the first method a strip or ring of bark is removed all the way around the stem.  The strip should be one-half to one inch wide.  Use a sharp knife make a cut through the bark in a circle all the way around the stem.  Next, make another cut around the stem, one-half to one inch below the first cut. Apply enough pressure to push the knife through the bark, but not enough to cut through the entire stem.  You will feel the knife cutting through the bark.  Next, peel back the bark from the stem using the point of the knife.%0A%0A%0A%0AThe second method frequently used for air-layering is to make an upward slanting cut half-way through the stem.  The cut should angled so that the length of the cut is about one inch long.  Use a sharp knife and constant pressure when making this cut.  Don't use too much force or you will cut through the entire stem.  Push a toothpick in the cut stem to keep it cracked open.%0A%0AOn the wound that has been created by removing the ring of bark or cutting halfway through the stem, dust the wound with rooting hormone.  It's easiest to apply the hormone powder using a small artist's brush.%0A%0ANow it's time to cover the wound with moist spaghnum moss.  The moss will provide  a moist environment for the new roots to grow into.  Soak the spaghnum moss in water for several hours.  Ring out the excessive water and pack the moist moss around the wounded stem section.  Use enough moss to form a football-shaped pack extending two or three inches above and below the wound.%0A%0AHold the moss in place by wrapping it with a plastic food wrap or aluminum foil.  Seal the bottom and top with a twist tie, rubber band or water-proofing tape to keep moisture from escaping.  If the plant is in full sun, use aluminum foil to reflect the sun light and keep the spaghnum from heating up too much.%0A%0AIt will take a month or two for new roots to form in the spaghnum moss.  When they do, cut the stem off just below the new roots.  Pot the rooted plant in it's own container and enjoy your new, compact plant! %0A %0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture, the University of Arizona, 520-626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on November 5, 2000%0A|April 19, 2001|
29|29|Protecting Plants From Summer's Heat.|	"We've Only Just Begun - to Sizzle" may not be the title of an old Carpenter's song, but it's likely the tune we'll be singing here in the desert as temperatures have already climbed past century mark.  Fortunately for us, we can escape into our air conditioned homes and offices.  But our plants are firmly rooted in the parching desert sun and heat. To help them through the rough times ahead, here are some pointers for Summer plant survival!%0A%0A	First, always make sure plants have an adequate supply of water.  Garden vegetables and flowers need to be watered daily, sometimes twice daily during our driest month - June.  So do patio plants in containers.  Newly planted trees and shrubs also need daily watering for the first few weeks, or until the monsoon rains arrive in July.  Only then should watering of newly planted trees and shrubs, even the likes of mesquite and jojoba, be spaced farther apart.  %0A%0A	For trees and shrubs that have been growing for a time, a year or more, watering depends on their type.  Non-desert varieties like citrus, oak, and privet will need a deep watering once each week.  Native and desert-adapted varieties such as palo verde, desert willow, and acacia can survive on their own in years of normal rain occurrence.  But normal years are few and far between so it's best to provide them a good soaking once or twice a month during hot, dry weather.  With substantial monsoon rains, watering on all types of established trees and shrubs can be reduced or curtailed.%0A%0A	Wilt is the most common symptom of moisture stress on plants.  Small garden plants and new plantings of all types are most inclined to wilt.  If you notice plants drooping in the heat of mid-day, cool them down.  This can be accomplished by hosing them off with cool water.  The water drastically reduces moisture loss from leaves and cools the plants.  As a result, the plants are once again able to draw more moisture from the soil than they loose through their leaves.    Water pressure within the plant returns causing them to perk up.  Remember, let the garden hose run on bare ground until cool water comes out.  Never hose down plants with hot water!%0A%0A	Shading plants will also help cut their moisture loss.  Shade cloth and row cover fabric can be purchased in garden centers and home supply stores.  Plants can be covered directly, or you can construct a simple wood frame to hold the shade cloth.   The frame should be positioned overhead or on the west side of plants to be protected.  Patio plants can be repositioned where they receive afternoon shade.  Moving them to a temporary location under a tree will also help.  Avoid pruning plants during the summer.  Removing too much leafy growth will expose the stems and branches to strong sunlight that can cause the wood to sun-scald.%0A%0A	Mulch is a must for summer gardens.  All plants benefit by having a layer of organic matter such as straw, compost, or cedar mulch.  A two to three inch layer will insulate the soil, keeping it from getting too hot and drying out.  After applying you mulch covering, pull it back slightly away from the base of the plants.%0A%0A	Finally, never apply sprays of garden chemicals when temperatures are above 90 degrees!  Heat and sunlight combined with chemical sprays can be toxic to plants.  If you must spray, do it early in the morning, when temperatures are cooler.  Better yet, try spraying with a strong jet of water.  This will control many common garden pests such as aphids and mites.%0A%0A	For more information this week's garden deomonstration will be on "Protecting Plants for Summer Sun & Heat".   It will be presented on Wednesday at 9:00 a.m. at the Pima County Extension Center, at 1:00 p.m. at the Wilmot Library, and on Thursday at 2:00 p.m. at Marana Planning Services on the Northeast corner of Orange Grove and Thornydale.%0A%0A%0AIssued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with U.S. Department of Agriculture, James A. Christenson, Director, Cooperative Extension, College of Agriculture and Life Sciences, the University of Arizona.%0A%0AThe University of Arizona college of Agriculture and Life Sciences  is an Equal Opportunity employer authorized to provide research, educational information and other services only to individuals and institutions that function without regard to sex, race, religion, color, national origin, age, Vietnam Era Veteran's status, or disability.  %0A%0A%0A%0A%0A%0A	%0A%0A%0A%0A%0A%0A|May 11, 2001|
21|30|Plant Care When Your Gone on Vacation|Before you leave on that long-awaited summer vacation, be sure your irrigation system is in good working order.  A system failure when your gone, in the heat of summer, could have disastrous consequences for you plants.%0A%0A	First, manually turn on your irrigation system and inspect the drip emitters.  Make sure water is coming out of all the emitters.  If you find one that's stopped-up, replace it.  If that doesn't work, then try replacing the quarter inch spaghetti tube from the main line to the emitter. Drippers can become clogged with soil or mineral deposits blocking the flow of water.  They can also be damaged by rabbits or other critters as they chew the dripper looking for moisture. %0A%0A	Make sure your irrigation controller is working properly.  Set the controller at least a week ahead of your vacation departure.  Set it to come on at a time when you will be able to observe the watering.  At the prescribed day(s) and time(s) the system is set to come on, go out and look to see if in-deed it has come on and water is flowing.  If not, you will have some time to troubleshoot the problem before you leave.  %0A%0A	The most common reason an irrigation control clock fails to open the valve is because the valve's solenoid burns out and needs replacement.  It's an easy thing to do yourself and a new solenoid can be purchased at hardware and home supply stores.  Just ask instructions from the sale person on how to install it.%0A%0A	It's best to have a friend or neighbor look in on your yard while your gone.  Program your irrigation to come on at a time that is convenient for your helper to come over.  That way, he or she will be able to see if the water has come on as programmed.  Also, give them instructions on how to turn the system on manually in case a problem occurs.  If for any reason, the manual setting on the controller will not function, the valve itself can be opened manually.  There is a handle on the valve with a directional arrow which can be turned to allow the water to flow through.%0A%0A	Container plants on the patio are especially vulnerable to insufficient or shipped waterings.  If you have an automatic watering system for your pots, set it to water more frequently than you would normally.  Always plan on the worst-case-scenario in terms of plant water needs.  Moving pots in full sun locations to shaded or semi-shaded locations will reduce heat stress and moisture loss.  Sun-loving plants will not suffer any adverse effects being in the shade for just a week or two.%0A%0A                Indoors, make special vacation arrangements for your house plants also.   Just as with patio plants, set house plants in locations out of direct sunlight and away from window heat.  %0A%0A	House plants should be watered thoroughly just prior to leaving on vacation.  After the pots have drained, they can be set in water-filled saucers.  As the soil begins to dry, water will be absorbed from the saucer up into the pot, keeping the soil moist.  This method should keep plants fresh for up to a week.  %0A%0A	For extended leaves, try draping clear plastic dry cleaning bags over your plants.  Don't cover them too tightly, it's important that some air can get in.  However, the plastic will trap some of the evaporating moisture and provide more humidity around your plants, thus reducing their water needs.%0A%0A	A number of "plant sitter" watering devices are available from local garden centers and also over the internet.  One especially effective one is ceramic cone hooked to a tube.  The tube is inserted into a container of water and the cone is pushed into the soil.  As the soil in the container begins to dry, water is wicked up the tube and out through the ceramic cone.  This and a number of other watering devices may be found at www.gardeners.com and other garden supply web sites.%0A%0A	Finally, nothing beats the human touch.  If you have someone who can occasionally come in to check and water your plants as-needed, it will be one less thing to worry about while your off having fun.%0A	%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161.%0A|July 6, 2003|
25|31|Desert Rose Care|One of the most important aspects of rose care here in the desert is watering.  Roses need frequent irrigation during hot weather.  In the spring, two to three waterings weekly are required when daytime highs are in the 80's and lower 90's.  As temperatures approach 95°F. increase watering to three to four times weekly.  %0A%0A	Flood or drip irrigation may be used to water roses.  But regardless of the system you use, make sure the water penetrates to a depth of 2 to 3 feet.  This deep watering not only stimulates deep rooting of your roses, but also keeps harmful salts washed down below the root system.%0A%0A	The best way to determine the depth of wetting is to measure the moisture level immediately after an irrigation cycle.  To do this, use a metal rod, such as a two foot long re-bar which can be purchased at hardware or building supply stores.  When the soil is moistened, the rod can be pushed in to the soil. Try pushing the rod down in several locations.  Because of rocks and other soil debris, the probe may strike one of these objects and give you a false reading. Try another spot.   Pull the rod up and measure the depth it penetrated.  The rod should go down at least 2 feet.  If it didn’t, adjust your drip irrigation to run longer or fill the basin deeper, and then test again.%0A%0A	To help conserve moisture and keep rose roots cooler, cover the soil with an organic mulch.  Straw, compost, chipped bark, ground western cedar, and pine needles all work well.  They insulate the soil from heat and slow moisture loss better than rock mulch.   To be most effective, the organic mulch layer should be 3 to 4 inches thick.%0A%0A	Besides abundant water, roses need heavy amounts of plant nutrients to stay healthy and happy.  In particular, they respond to regular applications of nitrogen and phosphorous.  Magnesium in the form of Epsom salts has also been touted by rose experts as a way to promote basal shoot development and overall health.  %0A%0A	The form nutrients take can vary.  Quick release, slow release and organic forms all have their place and one may not be better than the other.  In my opinion though, the slow release forms of nutrients make the most sense.  That’s because they release a constant but mild level of nutrients.  This avoids the ‘feast or famine’ condition that can arise when using standard granular fertilizers such as ammonium phosphate.  Keep in mind that slow -release fertilizers used here in the desert only last half the time indicated on the package label.  So a 3 month timed-release product will last just 6 weeks.  %0A%0A	If you use a standard granular fertilizer or rose food, make applications of these every 4 weeks up to June.  Then cut the amount per application in half, from June through August, to allow roses to rest during the heat of Summer.   The American Rose Society recommends a 10-10-10 or similar analysis fertilizer.%0A%0A	Roses can also be supplied their nutrients in organic form. The American Rose Society calls for the application of: one cup bone meal, one cup cottonseed meal, one-half cup blood meal, one-half cup fish meal, and one-half cup epsom salts per rose bush.  This spring application should be followed up with an application in September to promote Novemberl flowering.%0A%0A	Liquid fertilizers can be used to supplement your rose fertilization.  Products like Peters, Shultz, and Miracle-Gro can be applied to bolster the plants nutrient levels as needed through the season.  In addition, roses may require periodic applications of iron.  If new leaves have yellowed, apply ‘chelated’ iron to the soil. %0A%0A	 Be on the look out for rose pests this spring including; aphids, mites and cane borers.  Aphids are soft-bodied green insects that attack soft new growth, causing leaves to curl.  They also secrete a sticky substance called ‘honeydew ‘ that imparts a varnish-like shine to leaves. %0A%0A	Mites are tiny, pencil-point sized, pests that attack the plant from the bottom and work their way up.  Leaves become stippled with yellow specks from their feeding and eventually fall off.  %0A%0A	Both mites and aphids can be controlled with a weekly hosing off with a strong jet of water from a hose-end attachment.  Spray both the top and undersides of leaves.%0A%0A	Rose cane borers can be prevented by applying a wood glue to any pruning cuts.  This will seal the wound and prevent the borer larva from entering and feeding in the stem.  %0A%0A	Visit the new Rose Garden at the Pima County Extension Office.  It will be one of many stops on the upcoming Master Gardener Home Garden Tour scheduled for Saturday, April 10th.  Tickets are available at Harlow Gardens, Rillito Nursery and at the Pima County Extension Office.  %0A%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |March 28, 2004|
30|32|To Prune, or Not to Prune - Citrus That is|When most of us think about pruning fruit trees, we envision those peaches, apples and plums we used to grow before moving to Tucson.  The pruning on those stone and pome fruits was done yearly and rather severely.  It was the only way to ensure the production of abundant and high-quality fruit.  But now, were growing citrus here in Tucson, and citrus is a fruit of a different color all-together.  %0A%0A	Citrus trees, whether orange, tangerine, grapefruit, lemon or lime are really large, over-grown shrubs; it just happens they produce delicious fruits.  They don’t grow as, nor should they be pruned like other fruit trees, trees, or for that matter even shrubs.  A little known fact about citrus is: the more green leaves there are, the more abundant and delicious the fruit will be.  Another interesting bit of information revealed to me by a seasoned orange grove manager is that the sweetest fruit are always located on the southwest side of the tree.  %0A%0A	Now as to pruning citrus; given that more leaves equates to more and better fruit, then prune only if you must and only using the proper techniques.%0A%0A	One of the first things people want to do with their citrus tree is to prune off the lower limbs.  In an effort to make citrus more tree-like,  it’s acceptable to trim up some of the lower branches.  However, those branches which shade the base of the trunk from exposure to direct sunlight should not be removed.  The bark on trunk, and also branches of citrus sunburn very easily when exposed to direct sunlight.  This sunburning of the wood will cause the bark and underlying cambium layer, which transports water and nutrients, to die!%0A%0A	It’s not harmful if branches hang all the way to the ground, although it might make it a little more difficult to fertilize under the tree.  Disease will not develop if the ends of lower branches touch the ground.  If you do decide to remove some of the lower limbs, cut them back to the trunk.  Don’t just cut the outer portions.  Chances are the remaining inner branch sections will not produce fruit anyway.  %0A%0A	Pruning cuts made on citrus trees, or for that matter trees in general, should not be treated with pruning paint or wound dressing.  These products only inhibit the tree’s natural healing process. Most contain tar or asphalt compounds that can actually harm the tree. %0A%0A	From time to time it may be necessary to prune errant branches; those growing into or too close to your house, patio or walkways.  Try to remove as few branches as possible.  If a large limb must be pruned off, don’t do it now!   Wait till mid-November when sun intensity has decreased and when pruning will not promote soft fall growth, more susceptible to freezing injury.  If a large limb is removed too late in the spring, new growth will not develop fast enough to shade exposed wood and sunburn will result. %0A%0A	If a large branch or branches must be removed during the spring and summer months, immediately whitewash any branches or trunk portion exposed to direct sunlight.  Use a solution of one part white latex paint to nine parts water for a whitewash to be applied to exposed bark.  The whitewash will reflect sunlight and prevent the bark from scorching. %0A%0A	Unlike lower branches, when pruning side or top branches, remove only the part of the branch causing the problem.  Prune it back to a branch fork, side branch or stem.  Don’t leave stubs that can cause a rot to move down into heathy wood.  Also, don’t use pruning paint. %0A%0A	Fruit on citrus can also sunburn.  When it does, a rounded, buff-colored patch develops on the side of the fruit most exposed to direct sunlight.   Fruit burn can occur on any side of the tree, but is usually on the south and west facing portions.  The types of citrus fruit most susceptible to sunburn are tangelos, tangerines and oranges.  Usually, fruit burn does not effect the quality of the fruit, only the appearance of the outer rind.  The only way to prevent it is to cover the tree with shade cloth from June through August.  %0A%0A	Finally, keep in mind that citrus, allowed to grow as large shrubs are healthiest and will produce the most and best quality fruit.  So, if your really into prune fruit trees, consider growing yourself a peach or apple tree.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |March 16, 2005|
31|33|How to Control Bumper Crop of Weeds|%0A	Home gardeners are having fits trying to control a bumper crop of weeds brought about by all our Winter rain.   Landscapes and gardens are choked with unwanted growth, and the weeds just keep coming.  To control them, it’s best to use a combination of mechanical and chemical measures.%0A%0A	First and foremost, it’s critical to kill the weeds before they become mature enough to produce seed.  One small weed plant can literally produce hundreds of seed that can later sprout and grow.  If the weeds haven’t matured, the best mechanical means of control is to cut them off with a hoe.  If your weeding areas of rock-mulched landscape the best type of hoe to use is the Action Hoe, also called a ‘Hula’ Hoe.  It has a triangular-shaped blade with a flat cutting bar that can be pushed under the rock mulch to slice through weeds but leave the gravel in place.%0A%0A	 When using a hoe of any type, in the garden or landscape, try to shave off weeds at the soil line rather than slicing into the soil. Many landscape plants and most flowers and vegetables are shallow-rooted. Cutting into the soil damages these fine, shallow roots. %0A%0A	If weeds are mature and have seed ready to drop, it’s best to hand-pull or cut them off to prevent the seed from falling.  Have a plastic bag on hand to stuff the seed laden weeds into.  For the taller growing weeds, it will be easier to cut them off at ground level.  Most weeds that sprouted up this winter were annual varieties, which means they won’t grow back from the roots. %0A%0A	As we’re now heading into the normally dry spring months, weed seeds will not have the moisture needed to continue sprouting and growing.  However, when rains return this summer so will the weeds, unless weed control products are used to prevent their return.%0A%0A	Chemical weed preventers, also called pre-emergent herbicides, can be applied prior to the Monsoon season to prevent weed seeds from germinating. As our Summer rains usually begin in late June or early July, the time to apply these pre-emergent chemicals in mid-June.  %0A%0A	Look for weed control products with labels like: Weed Stopper, Weed and Grass Preventer, or Weed Preventer on your garden center shelf.   The chemicals, listed as the active ingredients in these products will be Surflan, sold as a liquid, or Amaze sold as a granular bagged product.  They’re the two most widely used pre-emergent (before weeds emerge) chemicals. They can be purchased at most places garden products are sold.  When applying pre-emergent herbicides it’s important to follow a few simple steps to insure their effectiveness.%0A%0A	To provide an adequate barrier to block the growth of weed seeds, these weed blocker chemicals need to be watered into the top layer of soil.  If allowed to lay on the soil surface, even for a few days, these chemicals will volatilize into the air and loose there effectiveness.  %0A%0A%0A	The watering in is a simple process.  After applying pre-emergent herbicide over open areas in the landscape, set some straight-sided cans randomly throughout the treated area.  Use a fan-type portable lawn sprinkler to water the area.  Leave the sprinkler on long enough to apply one-half inch of water.  You can use the cans to measure the depth of water applied.  When all of the cans have filled with one-half inch of water, the herbicide has been sufficiently soaked in.  %0A%0A	Remember that the pre-emergent herbicide creates a chemical barrier in the soil to prevent weed seedlings from growing.  If you break this chemical barrier by hoeing, pulling weeds, planting or otherwise disturbing the soil it will break this chemical barrier.  In most cases the herbicide barrier will provide weed control through the Monsoon Season.%0A%0A	Finally, sprays are available to kill existing weeds.  Among the most popular is the weed killer - Glyphosate.  It comes in premixed and concentrate forms and can be used to kill perennial weeds, such as Witches Broom, Sandbur and Bindweed, roots and all so they won’t grow back.  It can be used anytime weeds are actively growing.  When in doubt whether a existing weed is an annual or perennial, and you want to use a spray control, use glyphosate%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |March 20, 2005|
32|34|Winter Pruning of Roses|Don’t mistake winter pruning of roses in Arizona with what you may have been familiar with in colder climates farther north.  Winter pruning here doesn’t involve severe pruning to removal heavily frozen canes.   Our canes don’t freeze, so our pruning is more a fine-tuning of the bushes to maximize new spring growth and bloom.%0A%0A	The first step in the pruning process is to eliminate crowding of the interior of the rose bush.  Growth of new canes can be so vigorous, that over time the crown of the plant becomes choked and in need of thinning.  Using a long-handled pruning loppers, to reach into the center of the plant and begin pruning out the smallest canes.  Prune them off as close as possible to the plant base.  Old, non-productive canes should also be removed.  After thinning, you should be left with 4 to 8 vigorous canes that are thumb-sized or larger in diameter.  If your bushes are young, the canes may not be quite as thick or numerous. %0A%0A	On mature rose bushes, the oldest canes will be a gray color and several inches across.  The most vigorous canes will be somewhat younger, not quite as thick and have a reddish green stem color.  These vigorous canes will over-time be allowed to replace the older, less vigorous ones.  Try to keep a balance of old, vigorous and young (green) canes.  %0A%0A	The next step in the pruning process is to prune all canes back to a height of 18 to 24 inches above the base of the bush.  Each cane should be pruned back to an outward facing shoot or dormant bud.  Shoots will be obvious, but dormant buds are harder to see.  They’re located at the base of leaf petiole.  So cutting just above an outward-facing leaf will insure that when the bud breaks dormancy, the new shoot will grow out and away from the center of the bush.%0A%0A	Directing growth outward is very important.  The more light which penetrates into the center of the rose bush, the more flowers the plant will produce.  So, try to eliminate any inward growing shoots, stems, or canes.  Over time, with proper pruning a standard rose can become very large and wide.  Keep this in mind when planting new rose bushes.  Allow for a minimum 3 foot spread per bush.  %0A%0A	Unlike all other plants I know of, pruned roses do require that the cuts be sealed.  This is done to prevent cane borers (various beetle larvae) from penetrating into and down the cut stem.  The best and easiest way to seal the cut ends is to dab on some Elmer’s glue.  It’s not toxic to the rose, is environmentally safe and does a great job of sealing the cut and keeping bugs out.  Apply the glue to all cuts one-half inch or greater in diameter. %0A%0A	In addition to pruning, this is also the time of year to plant new bare-root rose bushes. %0ARight now, bare root rose bushes are available at local garden stores in an array of colors.  They should be planted in the garden as soon after purchasing as possible to prevent the roots from drying out.  Roses grow very well in containers and raised beds.  If you preparing a bed for planting in the ground, mix in lots of organic matter prior to planting.  After planting, keep the soil moist to encourage new root growth.  	%0A%0A 	%0A	%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |January 15, 2006|
33|35|Caution When Selecting - Using Weed Killers|Just look at the shelves in garden departments and you’ll find them stock to overflowing with weed killers.  But some of those products can be very dangerous for home gardeners to use.  Not in terms of harm to people, pets or wildlife, but some of these products can be very harmful to valuable landscape plants.  Chief among them are products containing a weed killer called Triox.%0A%0A	Triox is a total vegetation killer!  It’s advertised for use on walks, driveways, along fences and other spots where no growth is desired.  But read the label information and what you’ll find is that Triox will damage or kill any desirable plant who’s roots it comes in contact with!  So applying Triox to a fence line, driveway, walk, or patio will surely allow this vegetation killer to move down into the soil where it is likely to contact underlying roots of surrounding desirable trees and shrubs.  In addition, a heavy rain can wash the Triox from the area of application to surrounding areas causing additional damage.  The bottom line for home gardeners - don’t use products containing Triox!  Be very cautious using any product labeled, vegetation or brush killer. They’re likely to have similar harmful effects.%0A%0A	Another herbicide product that can damage trees and shrubs is the lawn weed killer - Dicamba.  If tree or shrub roots are growing in your lawn area, and you apply Dicamba it too can be absorbed by tree and shrub roots, damaging these desirable plants.  It’s common for mature trees to have roots that extend out as much as 4 times farther than the spread of the branches.  Shrubs also have roots extending out well beyond the ends of their branches.%0A%0A	Fortunately, one of the most popular weed killers for home gardeners - Roundup - is relatively safe to use.  It is not absorbed by plant roots and has no harmful effects in the soil, unlike Triox.  It kills weeds by being sprayed on, and absorbed by, their leaves and other green tissue such as green stems.  It moves from the leaves to the roots via the plants internal cambium tissue.  Once it reaches the roots, it kills the entire plant. %0A%0A	Roundup is actually the well-known brand name for the chemical ‘Glyphosate’.  It is available as the active ingredient in a number of herbicide products such for the control of perennial broadleaf and grassy weeds.  It’s one of the most effective products for the control of certain hard-to-control woody-stemmed weeds such as our notorious Desert Broom.  %0A%0A	The best way kill Desert Broom and other woody brush is by applying undiluted Roundup concentrate directly to cut stems at the base of the plant.  This application should be made while the plant is actively growing.  So, it’s best to hold off treatment until late March or early April.  At that time, cut the stems of Desert Broom off close to the ground and immediately paint them with concentrated Roundup.  The material will be absorbed through the cuts and transfer directly to the roots.%0A%0A	The product you select should have a concentration of at least 18%25 Glyphosate.  The simplest way to apply the weed killer is to pour a small amount in a styrofoam cup and use a small paint brush to dip and paint the weed killer on to the cut stems.  “Because of the potential for contamination, do not pour any left over Glyphosate back into the original container.  Just use it up by applying it to the cut stems.%0A	%0A	“Spring Fertilization of Gardens and Landscapes” will be the topic for this week’s garden demonstrations. They will be presented on Wednesday at 9 a.m. at the University of Arizona - Pima County Extension Center, 4210 N. Campbell Ave (central); and at 1 p.m. at the Wilmot Library, 530 N. Wilmot Road (east), and on Friday at 1 p.m. at the Oro Valley Library, 1305 W. Naranja Drive (northwest). %0A%0AGarden centers and nurseries here in Tucson and throughout Southern Arizona stock a wide array of plants.  Not all of them are well-suited to the desert.  In fact, a large number of the varieties of plants for sale are not true desert plants and may require significant amounts of water to survive our harsh, often drought-stressed environment.%0A%0A	Before purchasing plants this spring, do your homework.  Find out whether the plant(s) your thinking about purchasing are desert native, desert adapted or water-dependant exotic species.%0A%0A	Desert native plants will require the least amount of care.  Once established these plants can survive on what Mother Nature provides in terms of water and nutrients.  Even during periods of drought native plants will survive; either by going drought dormant or by self-pruning to reduce moisture loss.  Prickly pear cactus shed their outermost pads.  Palo verde drop leaves, stems, sometimes even branches to reduce their water needs.  %0A%0A	There are a wide variety of Southwest desert natives to choose from.  Selections of trees include; Blue, Foothills, and Desert Museum  Palo Verdes, Arizona Rosewood, Catclaw Acacia, Texas Honey Mesquite and Ironwood.  Some good choices of desert shrubs are; Creosote Bush, Chuparosa, Autumn Sage, Fairy Duster, Texas Rangers, and Brittlebush.%0A	%0A	Desert-adapted plants are those able to tolerate our desert environment in terms of heat and drought tolerance.  But during hot, dry periods they will require periodic irrigation.  Selections of these desert-adapted trees include; South American Mesquites, Texas Honey Mesquite, Sweet Acacia, Western Soapberry, Gregg Ash, and Kidneywood.   Some desirable desert-adapted shrubs include; Yellow Oleander, Red and Yellow Birds-of-Paradise, Emu Bush, Feathery Senna, Poverty Bush, Bush Lantana and Mexican Honeysuckle.  %0A%0A	In addition to trees and shrubs for low water use desert landscapes, cacti and succulents are also great choices.  Native Saguaro, Barrel, Hedgehog and Prickly Pear Cacti need little attention after establishment.  Agaves are also great drought-tolerant plants for desert landscapes.  Some of the best for home gardens include; Octopus Agave, Hauachuca agave, Twin-flowered agave and Holly agave.  %0A%0A	For landscape color, there are many desert perennials to choose from.  Those that can manage on just one watering per month during hot weather include; Penstemon, Angelita Daisy, Desert Marigold, Desert Zinnia, and Paper Flower.  Perennials that need a little more frequent watering (every week or two) include; Peruvian Verbena, Calylophus, Chocolate Flower, Golden Dyssodia and Guara.  %0A	%0A	In general, plants that use the most water are annual flowers like petunias, geraniums, zinnias and marigolds.  It’s best to limit the use of these flowers to a few pots for seasonal color on the patio.  Summer vegetables like tomatoes are also high water users, so if your planting a garden, limit it’s size or grow your vegetables in containers.%0A	When shopping at local garden centers and nurseries it’s best to avoid unfamiliar varieties of plants that don’t have the ‘desert look’.  Plants with lots of large, soft leaves are probably not adapted to desert conditions.  Many of these plants come from wholesale nurseries in California and are best suited to their milder growing conditions. %0A%0A	Consult reference books and internet sources for listings of additional recommended desert plants and their watering requirements.  Among the best books to consult are: Landscape Plants for Dry Regions, by Jones and Sacamano; and Plants for Dry Climates by Duffield and Jones.  An on-line data base of recommended desert landscape plants for Southern Arizona is available at: www.ag.arizona.edu/pima/gardening.%0A%0A%0A	%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161. %0A	%0A%0A	|February 19, 2006|
34|36|How to Stimulate Root Growth of Garden & Landscape Plants|Plant roots are the foundation of plant growth, from the smallest flower to the largest tree.  They hold plants in place and absorb the water and nutrients necessary for growth.  If roots aren’t heathy and vigorous, the plant will be weak and may eventually die.  But roots can be stimulated and encouraged to grow by following just a few simple steps.%0A%0A	Regardless of the plant, at the time of planting, the outer edge of the root ball should be scratched, scuffed or in some fashion, roughened.  The object is to loosen and pull some of the root tips out from their tight adhesion to the root ball.  In so doing, these roots will immediately begin growing into the surrounding soil after planting hastening the plant’s establishment.%0A%0A	For small plants like annual flowers and vegetables in 2 to 4 inch pots, this pulling of the roots is best done with a table fork.  The root ball should not be pulled apart, but the edge of the ball and outer roots should be scratched enough to loosen the roots.  For larger herbaceous garden plants or woody landscape plants in one gallon size and up, I prefer using a standard three-pronged garden fork to loosen the outer edges of the root ball.  %0A%0A	Don’t worry if in the process of loosening the root ball, some of the roots are torn off.  This will happen, especially on the small, fine-rooted herbaceous plants.  New roots will form where the old roots tore away.  In fact, many roots will branch and form multiple roots to replace the ones lost.  This root branching will increase plant vigor!  %0A%0A	For larger landscape trees and shrubs, in addition to scratching and pulling the finer roots, it will be necessary to cut larger circling roots when present.  Any finger-sized roots circling the outer edge of the root ball should be cut off with a sharp knife or hand pruners.  If not removed, these large circling roots will cause the plant to be stunted and poorly anchored. %0A%0A	To encourage rooting of garden plants including flowers and vegetables, mix lots of organic matter into the bed at the time of planting.  The organic matter can be bagged topsoil, potting soil, peat, bagged compost or manure.  In addition, mix in a fertilizer high in phosphorous such as ammonium phosphate (16-20-0) or bonemeal (4-22-0) at the rate of 1 pound per 100 square feet of garden bed area.  Mix the fertilizer into the top 12 inches of soil.  %0A%0A	Phosphorous is the only substance that can be mixed into the soil to directly stimulate root growth.  Other products marketed to promote root growth, such as Vitamin B-1, work under controlled laboratory conditions but are not effective when used in gardens and landscapes.%0A%0A	Although garden beds should be amended with organic matter, if your digging to plant individual plants (trees, shrubs, vines, etc.) do not add organic amendments.  Both native and non-native landscape plants should be planted directly back into the soil removed from the planting hole.  Creating a rich soil in the planting hole may sound like a good idea, but it’s not! Rather than encouraging roots to grow, a hole with organic amendments creates a ‘pot-in-the-ground’ from which roots have a very difficult time escaping.  Just be sure to dig a hole 2 to 3 times wider than the root ball.  This will loosen the soil and is the best way to encourage roots to expand out rapidly from the root ball.%0A%0A	  %0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161.|April 9, 2006|
35|37|Caution When Selecting - Using Weed Killers|Just look at the shelves in garden departments and you’ll find them stock to overflowing with weed killers.  But some of those products can be very dangerous for home gardeners to use.  Not in terms of harm to people, pets or wildlife, but some of these products can be very harmful to valuable landscape plants.  Chief among them are products containing a weed killer called Triox.%0A%0A	Triox is a total vegetation killer!  It’s advertised for use on walks, driveways, along fences and other spots where no growth is desired.  But read the label information and what you’ll find is that Triox will damage or kill any desirable plant who’s roots it comes in contact with!  So applying Triox to a fence line, driveway, walk, or patio will surely allow this vegetation killer to move down into the soil where it is likely to contact underlying roots of surrounding desirable trees and shrubs.  In addition, a heavy rain can wash the Triox from the area of application to surrounding areas causing additional damage.  The bottom line for home gardeners - don’t use products containing Triox!  Be very cautious using any product labeled, vegetation or brush killer. They’re likely to have similar harmful effects.%0A%0A	Another herbicide product that can damage trees and shrubs is the lawn weed killer - Dicamba.  If tree or shrub roots are growing in your lawn area, and you apply Dicamba it too can be absorbed by tree and shrub roots, damaging these desirable plants.  It’s common for mature trees to have roots that extend out as much as 4 times farther than the spread of the branches.  Shrubs also have roots extending out well beyond the ends of their branches.%0A%0A	Fortunately, one of the most popular weed killers for home gardeners - Roundup - is relatively safe to use.  It is not absorbed by plant roots and has no harmful effects in the soil, unlike Triox.  It kills weeds by being sprayed on, and absorbed by, their leaves and other green tissue such as green stems.  It moves from the leaves to the roots via the plants internal cambium tissue.  Once it reaches the roots, it kills the entire plant. %0A%0A	Roundup is actually the well-known brand name for the chemical ‘Glyphosate’.  It is available as the active ingredient in a number of herbicide products such for the control of perennial broadleaf and grassy weeds.  It’s one of the most effective products for the control of certain hard-to-control woody-stemmed weeds such as our notorious Desert Broom.  %0A%0A	The best way kill Desert Broom and other woody brush is by applying undiluted Roundup concentrate directly to cut stems at the base of the plant.  This application should be made while the plant is actively growing.  So, it’s best to hold off treatment until late March or early April.  At that time, cut the stems of Desert Broom off close to the ground and immediately paint them with concentrated Roundup.  The material will be absorbed through the cuts and transfer directly to the roots.%0A%0A	The product you select should have a concentration of at least 18%25 Glyphosate.  The simplest way to apply the weed killer is to pour a small amount in a styrofoam cup and use a small paint brush to dip and paint the weed killer on to the cut stems.  “Because of the potential for contamination, do not pour any left over Glyphosate back into the original container.  Just use it up by applying it to the cut stems.%0A	%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161. 	%0A%0A	|August 24, 2006|
36|38|Comparing Garden and Landscape Fertilizers|There’s a dizzying array of fertilizers on the shelves of garden and home supply stores.  Citrus foods - fruit tree fertilizers - tree and shrub foods - tomato and vegetable fertilizers - rose foods - flower foods - general purpose fertilizers and the list goes on and on.  You’d think you need a special fertilizer for every sort of garden and landscape plant you have!  Truth is, having just two or three fertilizers on hand is enough to cover all of your garden and landscape needs.%0A%0A	When it comes to landscapes your trees, shrubs, vine and ground covers can be feed with one product - a fertilizer high in nitrogen.   All of these, even the ones that flower periodically, are considered foliage plants.  Their leafy growth and overall health is dependant on nitrogen.  If you look on the fertilizer label, nitrogen is the first number listed.  In the case of landscape plants, this number should be the highest.  In fact, I often use nitrogen alone, in the form of ammonium sulfate (21-0-0) to fertilize my landscape plants.  It does the job to stimulate lush, leafy green growth.  It’s also the fertilizer of choice for citrus trees!  %0A%0A	Other fertilizers typically high in nitrogen are tree and shrub foods and lawn fertilizers.  A caution about using lawn fertilizers to feed trees and shrubs - don’t use weed and feed products!  They contain herbicides that can damage landscape plants. %0A%0A	Garden plants: including roses, annual and perennial flowers, fruiting vegetables such as tomatoes and peppers, and fruit trees (other than citrus) call for the use of a fertilizer containing both nitrogen and phosphorous.  Flower and fruit formation is stimulated by the addition of phosphorous, the second number listed on the fertilizer label.  Ammonium phosphate (16-20-0) is an excellent fertilizer for garden plants!  Speciality flower, vegetable and fruit fertilizers (although more expensive) can also be used and are interchangeable.  A flower fertilizer can be used for fruits and vegetables just as a vegetable fertilizer can be used for flowers and fruits. Keep in mind that unlike nitrogen, phosphorous has to be physically mixed into the soil, at the time of planting, to be effective!%0A%0A	Patio container plants have unique fertilization needs.  Because their roots are  restricted and their source of nutrients limited to rather sterile potting soil, they must receive a full compliment of nutrients on a regular basis.  In addition to nitrogen and phosphorous, container plants also need potassium, magnesium and a full compliment of micro-nutrients such as iron, manganese, and zinc.  Even if the potting soil you use has nutrients added, they’re rapidly used up and must be replaced.  %0A%0A	Although I don’t recommend timed-release fertilizers for garden and landscape plants, I do for plants in pots.  There are a number of timed-release fertilizer products to choose from such as  Osmocote, Vigoro, and Dynamite brands.  Choose a balanced fertilizer with similar levels of nitrogen, phosphorous and potassium.  Balanced fertilizers are well suited to a wide variety of foliage, flowering and fruiting plants. %0A%0A	Finally, fertilization is not necessary for all plants.  Our desert soils provide for the nutritional needs of native plants.  Leguminous trees like mesquite, palo verde and acacia produce their own nitrogen in root nodules through a process called nitrogen fixation.  However, non-native landscape plants do benefit greatly for regular fertilization, and it’s a must for  garden and container grown plants!%0A%0A%0A	%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161. %0A|April 29, 2007|
37|39|Squelch Those Winter Weeds Now|There are two important times to control weeds in the desert Southwest.  One is just prior to the summer monsoon season.  The other is now -  in advance of our winter rainy season!%0A%0A	Most weeds that sprout up in our gardens and landscapes are of the summer or the winter annual weed varieties.  Winter annuals begin germinating with the first rains of our cool season, usually in December and January.  The most common include; mustard, filaree, bladderpod, London rocket and velvetweed.  But there are many others. %0A%0A	Regardless of the type, most annual weeds can be controlled with pre-emergent herbicides (weed killers) which are applied before weeds emerge. They all work in a similar manor, by creating a barrier in the top layer of soil that kills weed seedlings shortly after they emerge from the germinated seed.   Because of their mode of action, pre-emergent weed control chemicals must be watered into the top layer of soil to be effective.  %0A%0A	Surflan is the most common pre-emergent weed control chemical available for homeowners.  It’s the active ingredient in products on the garden center shelf labeled weed impede, weed preventer or weed stopper.  As a liquid, it must be applied to the ground with a pump-up sprayer.  %0A%0A	Another commonly available pre-emergent herbicide is a combination of Surflan and Benefin (another pre-emergent herbicide) in a granular product called Amaze.  It can be applied with a whirlybird or troth-type fertilizer/seed spreader.  In addition to treating landscape areas, Surflan and Amaze can also be used in flower beds.  The pre-emergent Treflan, sold under the product name ‘Preen’ can be used to control weeds in vegetable and flower beds.  It’s also available in most retail garden outlets.%0A%0A	Prior to application read follow all label directions for the product being used.  The label will provide instructions on application including the amount of material to be applied to a given area.    %0A%0A	Regardless of the specific chemical, these pre-emergent herbicides must be watered into the top layer of soil to be effective. You can wait to apply the herbicide just before a predicted rain event, or for insured success, water it in using a portable sprinkler.  The best type of sprinkler to use is a fan-pattern oscillating lawn sprinkler that can be connected via garden hose to an outdoor hose bib.  They’re relatively inexpensive and can be purchased at most garden centers and hardware stores.%0A%0A	To determine when you have applied enough water to soak the pre-emergent herbicide into the top layer of soil, set several straight-sided cans randomly in the area to be watered.  Run the sprinkler until you have collected an average one-half inch of water in the cans.%0A%0A	During the effective period of the herbicide (usually 3 or 4 months), try not to disturb the protective weed barrier.  Hoeing, digging or otherwise disturbing the top layer of soil will break the invisible chemical barrier and allow weeds to grow through.  %0A%0A	If weeds sprout up prior to your application of pre-emergent herbicide, pull them out by hand, hoe them out or spray them with a post-emergent weed killer.  One of the best is glyphosate, the active ingredient in several non-selective weed killers including Roundup.  Glyphosate is a systemic herbicide that kills both annual and perennial weeds, roots and all.  During the winter months, in cooler weather, allow a week or two for glyphosate to kill the treated weeds.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161.   %0A|December 16, 2007|
38|40|Household Soaps Offer Benefits to Home Gardeners|Soap isn’t just for washing dishes anymore!  It’s a very important tool for gardeners - one of the best controls for a number of common plant and garden pests.  It also can be used to make water ‘wetter’ to improve the effectiveness of herbicide sprays and to overcome the water-shedding properties of ‘hydrophobic’ soils.%0A%0A	As an insecticide, the properties of soap are well known.  Commercial insecticidal soaps such as ‘Safer’ have been developed specifically as a bio-rational control for a number of bad bugs including; aphids, mites, white flies, thrips, lace bugs, mealy bugs and others.  Although insecticidal soaps are specifically designed for insect control, household dish washing soaps are also very effective in controlling these same pests.%0A%0A	Of all the household dish washing detergent brands, ‘Dawn’ is said to have the best insecticidal properties.  Other brands will also be effective, but avoid lemon scented soaps because of their potential to cause injury to plant leaves and flowers.%0A%0A	A mild soap solution is all that’s needed to take care of pesky bugs.  Mix one tablespoon of liquid dish washing soap in one gallon of water.  Or for smaller jobs, mix one-half teaspoon of soap in  a pint-size spray bottle of water.  When applying the soap solution, be sure to spray both the upper and lower sides of the leaves.  Repeat sprays on a weekly basis until your insect  problem is under control. %0A%0A	In addition to controlling many pest insects, soap sprays will also remove the varnish-like ‘honeydew’ secretions on leaves deposited by aphids, mealybugs and whiteflies.  After the soap spray has been applied to the affected leaves, wait until the spray dries then hose it off with a strong spray of water from your garden hose attachment.  The soap loosens the honeydew coating and floating it off the leaf surface.%0A%0A	For the home gardener, soap also helps to make water ‘wetter’!  Soap is a surfactant or wetting agent that helps water spread out evenly over the leaf surface.  As a result, a small amount of soap mixed into herbicide or fungicide sprays increases their effectiveness..  In the case of herbicides, more active ingredient is absorbed by the weed and the killing action is enhanced.  With fungicides, better coverage increases the effective shield created to prevent  fungal spores from penetrating the leaf surface.%0A%0A	As a wetting agent added to herbicide and fungicide sprays, only a few drops of liquid dishwashing detergent are needed in one gallon of spray material.  To reduce foaming, add the drops of soap after filling the sprayer with water.  Then, gently agitate the sprayer to disperse the soap.%0A%0A	The wetting properties of soap are also useful for soils that become ‘hydrophobic’. Soils that shed water and are difficult to wet are referred to as ‘hydrophobic’.  This often occurs in container potting soils consisting of mostly peat.  If the peat becomes too dry, it develops an affinity for repelling water. It also shrinks!  So, when these container soils are watered it may seem as though the water is being absorbed, but in reality the water is just running down the gap created between the pot edge and the shrinking soil.  %0A%0A	To wet hydrophobic soils fill a watering can and add several drops of liquid dish washing soap to the water.   Slowly apply this soap solution to the soil.  The soap breaks the surface tension of the dried soil and allows the water to be absorbed.  If the hydrophobic condition redevelops, apply another soap treatment.%0A%0A	Hydrophobic soils also develop in lawns.  The solution is the same - household dish washing soap!  %0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161. |December 23, 2007|
39|41|January 13, 2008|Think you have trouble coping with dry air and cold temperatures during the winter months - well so do your house plants!  		%0A%0A	 When our homes are closed up, especially in the winter with the heat on, the air becomes bone dry!  As a result, humidity-craving house plants suffer!  Leaves dry out, and as they do, the margins of leaves turn crisp and brown.  Dry air can also result in and yellowing and dropping of the lower leaves.  %0A%0A	Winter chills can also come over our house plants when they’re located too close to windows and doors.  Cold and drafty air will cause plant leaves to develop brown or black spots and drop off.  In general tropical varieties of potted plants don’t like temperatures below 55 degrees F.  On frosty nights, move them  back at least 3 feet from window panes and 6 feet from entryway doors.  %0A%0A	There are many ways to combat dry air indoors, but contrary to popular belief, misting isn’t one of them!  Measures that do work include using a home humidifier, grouping plants together and setting plants on water filled gravel saucers. %0A%0A	The saucers should be over-sized, to allow moisture evaporating off the gravel surface to flow up, around and into the plants.  Use a plastic plant saucers!  Clay saucers are porous,  allow moisture to seep out, potentially damage carpeting or other flooring materials.  %0A%0A	Fill the saucers nearly to the top rim with fine gravel.  I like aquarium gravel. It’s clean and attractive, and the small gravel size provides more surface area for more evaporation and higher humidity!  As the pot will sit on top of the gravel surface, the water level in the saucer should be a half inch or so below the bottom of the pot.  This will provide enough room for drainage water without overflowing the saucer.  Never let the bottom of the pot sit in the water!  Accumulated salts can be reabsorbed by the soil, damaging the plant.   Every month or two, empty water out of the saucers and refill with fresh water.%0A%0A	Over-watering during the winter months can result in yellowing and leaf drop.  It can also cause plants to be stunted, with an absence of new growth. Water-soaked roots are prone to root rot diseases which, in turn, can result in loss of the entire plant!%0A%0A	Potting plants in a well-drained container soil mix will improve drainage and make over-watering less likely.  It's a good idea to allow plants to go longer between waterings in the winter than you would during other parts of the year.  Most potted plants are not actively growing in the winter and thus do not require as much water as they would other times of the year. I suggest using a moisture meter to determine when your potted plants need watering. Moisture meters are inexpensive and available at most garden supply outlets; and best of all, they really do work!%0A%0A	Watering with chilled tap water can damage plants, especially tropical house plants. This is a problem in the winter when water pipes running into the house become cold.  Always use room temperature or water slightly warm to the touch.  Some plants are also sensitive to chemicals added to our tap water, including chlorine or fluoride. Letting the water set overnight in a watering can or other open container will allow these chemicals to evaporate out, making the water safer for your house plants.  If you collect rain water, use it to water your potted plants!  It’s totally free of chemicals and salts and may even contain some beneficial trace minerals.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161. %0A|January 13, 2008|