1|12|Growing Citrus in Tucson |In the new world citrus was introduced by the Spaniards in the 16th and 17th century. In Florida, by the explorer Ponce De Leon, and here in Tucson by Father Kino and other Spanish missionaries. %0A%0AAlthough citrus has been grown in the Americas for at least 400 years, known records of citrus cultivation date back nearly 2600 years. The sweet orange was known and cultivated in China for at least 600 years before Christ. It is believed that the citrus species originated from the warm southern slopes of the Himalayan Mountains. Early primitive forms of the orange, mandarin and pummelo were brought into China. %0A%0AMandarins were first mentioned in Chinese literature in 200 B.C. and like the lemon, probably originated in India and Burma. The lime is known in a wild state only on the Malay Peninsula and spread from there to India and then to the rest of the world. The grapefruit is a relative newcomer, appearing to have arisen in the West Indies as a mutation of the pomelo which was brought there from Asia by a Scottish sea captain. %0A%0ANow, getting down to the business of how you can grow citrus. First, make sure your yard is in a warm enough location for citrus. Generally, avoid planting citrus if you live along the washes and rivers. These areas are colder than most, generally too cold for even the hardier forms such as kumquats and calamondins. Of intermediate cold hardiness are grapefruit, oranges, mandarins and tangelos. They can tolerate short periods of temperatures in the low 20 degree range. Eureka and Lisbon Lemon are damaged below the mid 20's. And finally, limes a suffer injury in the upper 20's. Look for mature citrus in your area. If you find them, along with Ironwood trees and Saguaro cactus then your in a warmer location conducive to citrus. %0A%0ANext you'll want to select the variety of citrus you want to grow. Oranges, tangelos and grapefruit being the most popular, here is information on the best varieties for the Tucson area. %0A%0AOranges: %0A%0AValencia is great for eating, but excels in it's juicing quality. Because doesn't ripen until February and March it should be planted in warmer locations or protected. It is a good producer, with yields more than 200 pounds of fruit per tree after 10 years. Once ripe, fruit can be held on the tree many weeks, only improving it's quality. %0A%0ATrovita, one of the Arizona sweet oranges is a variety with excellent quality. Sweet and juicy with few seeds, the fruit of Trovita ripen in January. Trees also have good cold tolerance, and are do well in our desert climate. %0A%0ADiller and Hamlin produce smaller fruit than the Valencia with eight to ten seeds per orange. Both produce oranges of excellent juicing quality, that begin ripening in December. Eating quality is good. Both are categorized as Arizona sweets, Diller actually originating from Arizona as a seedling. %0A%0ARed Oranges while varying in color are well-adapted and ripen during the same season as other sweet oranges. Taroco, Moro, Ruby and Sanguinelli are named red or pigmented type blood oranges. %0A%0ATangelos: %0A%0AMinneola tangelo is known as the "Honey Bell" in Florida because of it's bell shape and honey sweet fruit. Extremely juicy, Minneola is excellent for eating, but wear a bib! The skin is an attractive deep reddish orange and is easy to peel. Fruit ripens in January to March, and may freeze in colder areas. %0A%0AOrlando is somewhat more cold hardy than the Minneola, with smaller rounded fruit. Fruit ripens from November to January. Orlando is very productive and is a rapid grower. Although rather seedy, the fruit is sweet and juicy. %0A%0AGrapefruit: %0A%0AMarsh sets the standard for white fleshed grapefruit. It has excellent flavor and is very juicy. It responds well to heat, which cause the fruit to become sweeter. Marsh is best harvested in April and May, but can be picked as early as November. The pink fleshed version of Marsh is called Redblush. Other than the color of the fruit, these trees are essentially the same. %0A%0AFor home planting, five gallon citrus trees are ideal from both the standpoints of cost and quick establishment . Select trees that have been grafted on hardy citrus rootstock. Trees grown on sour orange rootstock have very good cold tolerance, important here in Tucson. Other highly recommended rootstocks include: Trifoliate, Troyer, Swingle, Carrizo, and Volkamer.%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 Stargardening column, on February 8, 1998%0A%0A|July 25, 2001|
3|6|Pruning Fruit Trees|To keep fruit trees healthy and productive it's necessary to prune them on a regular basis. Now, during the dormant season, is the time for pruning and training of deciduous fruit trees, such as apple, peach, pear, apricot and figs.  %0APruning simply means the removal of wood, whereas training refers to pruning plants to a specified shape. Training is very important during the early life of a fruit tree. Pear and apple trees are generally trained to a modified central leader for a strong framework of branches. Peach, nectarine, and plum trees are best trained to an open center for a wide-spreading tree. %0A%0APruning trees each year is necessary in order to maintain their shape and help regulate the size and quality of the crop. If trees are grafted, sprouts from the seedling rootstock should also be removed. %0A%0AThe initial training of fruit trees comes at the time of planting. Apple and pear trees, when purchased, are normally unbranched plants, called whips, about 4 feet tall. These should be cut back to about 3 feet. After the first year, retain only the dominant central shoot (young trunk) and three or four branches spirally arranged around the trunk. The lowest branches should not be lower than about 2 feet above the ground. %0A%0AWhen planting peach trees, cut the tree back about knee high leaving several spirally arranged branches on the trunk. Reduce the length of these side branches to several buds. Remove all lower lateral branches flush with the trunk, and all suckers from the rootstock. The objective should be to develop three or four primary framework branches and an open center. Plum trees should be pruned much the same as peach trees, but they should have more usable branches and these should be pruned more lightly than the peach. %0A%0AIn young apple and pear trees, a central shoot (young trunk) is developed. This is accomplished by removing or spreading competing shoots, allowing only one vertical shoot to grow in the center. The central leader should be cut back each year at about 3 feet above the highest set of side branches. This is the central axis from which side limbs develop. %0A%0ADuring the first dormant season after planting the peach, select three basic framework branches and cut them back about two-thirds of their length. Retain two strong lateral shoots at or near the point of each cut to further increase the basic framework from three to six branches. The next year, cut each of these six branches back to about two feet from the point of their connections to the original three branches. Again, make the cut near two strong laterals to increase the framework to 12 branches originating from one, two and three year old wood. %0A%0APlum trees tend to develop open centers naturally without the precise procedure outlined for peach trees. With both young and mature deciduous trees in general, remove branches that interfere with the basic framework. Remove branches that rub against each other. Also remove branches that have weak, narrow crotch angles. When branches are growing closely parallel, remove the weaker of the two, or the one less desirably located. %0A%0AMature apple and pear trees should not be pruned severely. Moderate annual pruning of a corrective nature is preferable to heavy pruning every three or four years. Heavy pruning upsets the balance of the tree, causing abnormal growth of shoots, also called water sprouts. Besides being weak, these sprouts are more prone to infection form fire blight bacterial disease. %0A%0APeach and plum trees should also be pruned yearly. Remove any crossing branches and those that are growing into the center. Then cut to outward-growing branches to check upward development. Do a fair amount of thinning out of crowded parts. During the growing season, rub off all water sprouts from the main branches within two feet from the trunk and all suckers from the rootstock. Most of the pruning should be done in February, but topping of vigorous shoots may be done in June. %0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona 626-5161.   %0AMaterial originally appeared in Arizona Daily Star gardening column, on January 31, 1999 %0A%0A|July 25, 2001|
4|8|Pruning is Key to Fruit Tree Vigor|Our unusually warm weather has caused fruit trees to emerge from their winter dormancy and begin to bloom. Even so, it's still not too late to prune fruit trees such as apple, peach, plum, and apricot. Anytime up to the point flower petals begin to fall, it's safe to prune. Watch out for those honey bees visiting the flowers. %0A%0APruning deciduous fruit trees should be done annually to stimulate quality fruit production. Don't confuse deciduous fruit trees with citrus. Citrus trees do not need, and should not be pruned! That's because the more leaves there are on a citrus tree, the larger and more numerous the fruit will be. %0A%0APruning of decidous fruits is a means to remove less productive branches, and with it, the needed thinning of fruit. It also is a way to stimulate the growth of new, vigorous branches that will bear fruit the following year. %0A%0AAll fruit trees should be pruned to remove dead, diseased or broken branches. Shoots which grow straight up into the tree, should also be removed. These are called water sprouts. They are fruitless, and will only rob fruit bearing branches of light and nourishment. Suckering shoots are also unwanted. They are stems that grow from the base of the trunk or from roots near the trunk. Clip them off while they are still small. %0A%0AFruit tree pruning falls into one of three categories. The first is called the "open center" system. This is used to prune peach, nectarine, and Japanese plum trees. Simply put, branching should be in the form of a wide bowl, radiating out from the trunk. The bowl is formed by 3 to 5 well spaced main, also referred to as "scaffold" branches. When purchasing a young peach tree, be sure to check for this basic open branching structure. Small, bare root trees, known as whips, can be purchased from mail order fruit tree nurseries. They are planted and cut back to single a stick, 30 to 36 inches tall. The new shoots that grow from below the cut can then be chosen to form future scaffold branches. %0A%0AOn larger peach , nectarine and Japanese plum, remove any branches that grow up through the center of the tree. Next remove any branches that compete for the same space. If two are growing parallel, one on top of the other, remove the weaker of the two. Remove any upward or inward growing branches. Upward growth will produce leaves, not fruit. Inward branches will clog the center and shade other fruiting branches. Cut off small twigs arising along the scaffold and secondary branches. Finally, thin side shoots that come from secondary branches. Removing every other one is a good general "rule-of-thumb" to follow. When you think you've pruned enough, take a break. Then come back and prune some more.%0A%0AWhen the fruit has set, and is the diameter of a dime, thin the fruit. Pick to leave just one peach for every 6-8 inches of stem or branch. This will allow enough leaves around that fruit to manufacture the sugars necessary to develop the fruit to it's maximum size and quality. %0A%0AApples and pears are pruned using the "central leader" system. In this form, one main shoot is allowed to grow up in the center of the tree. Branches then arise from this "central leader" or trunk. The first tier or "whorl" of branches should be located 24 to 36 inches from the ground. Four to six branches should radiated out from the trunk in all directions to resemble the spokes of a wheel. The branches, however, should not all originate from the same point on the trunk, but rather be spaced a few inches apart on the trunk. %0A%0AA single whorl of four to six branches is sufficient for dwarf trees. A second whorl of branches should be developed on semi-dwarf and standard apple and pear trees. This whorl of four to six branches should be positioned about 36 inches above the first whorl. Branches or shoots selected for each whorl should all be about the same size. If one is much larger it will command the bulk of growth resources, leaving the others stunted. %0A%0AApricot, cherry and European plum are pruned using the "modified central leader" system. This form is basically the same as the central leader system, except that the central leader is "tipped" or pruned back each year to a side shoot below it. This side shoot then becomes the dominant leader, but only for one year, as it too is cut back the following year. Annual pruning of the central or dominant leader prevents the tree from getting too tall. It also stimulates a fuller tree with more fruiting side branches. %0A%0ARegardless of the basic system being used, all fruit trees will require the removal of dead wood, crossing or rubbing branches, inward growing branches, and competing branches. On apple trees, such as dorsett golden, care should be taken not to remove fruiting spurs. The spurs are short nubby stems. They arise from the branches, producing flower buds and fruit. They remain fruitful for many years. %0A%0AFinally, remember to thin fruit shortly after it forms. If fruit set is numerous, knock off some of the fruit with a flail made form a piece of garden hose. The remaining fruit can then be thinned by hand to a spacing of 6 to 8 inches apart for apples, peaches, plum and pears. This will ensure that the remaining fruit be the largest and highest quality possible. Apricot, cherry and European plum are pruned using the "modified central leader" system %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 February 13, 2000%0A%0A|July 25, 2001|
6|9|Fruits of the Desert|Well, maybe we can't grow apples like Washington State or peaches like Georgia, but with the right varieties, good fruit can be grown here in the desert. The key to success is choosing varieties of fruit that have a low chilling requirement.%0A%0ADeciduous fruit trees; apples, peaches, apricots, pears, and plums need a minimum amount of cold during the winter to properly grow and produce fruit. Many varieties of fruit trees need more cold than we typically receive here in Tucson. The ones that require the least amount of cold temperatures (low chill) are the ones we can grow. They include; ‘Anna' or ‘Dorsett Golden' apple; ‘Desert Gold' or ‘Flordaprince' peach; ‘Orient', ‘Floridahome' or ‘LeConte' pear; ‘Katy', ‘Gold Kist', or ‘Castlebrite' apricot, and ‘Santa Rosa' or ‘Satsuma' Japanese plum.%0A%0AFor fruit to form, pollination of the flowers must occur. Some fruit trees will pollinate themselves and are termed self-fruitful. Apricots are self-fruitful, so only one tree needs to be planted to produce fruit. Other fruit trees will not pollinate themselves and are termed self- unfruitful. Therefore two varieties must be planted for fruit set to occur. This is called cross- pollination. Peaches, and pears are self-unfruitful and require cross-pollination. Apples and Japanese plums are also generally self-unfruitful, but ‘Anna' apple and ‘Santa Rosa' plum will set fruit fairly well without cross-pollination.%0A%0AChoosing the right location to grow a fruit tree around your home is another important consideration. Fruit trees need full sun to grow and produce fruit. They also need a well drained soil. To check drainage, dig a hole about the size of a five gallon container in the location you intend to plant your tree. Fill it with water, and after the water drains out, fill it again. If after the second filling, water drains out of the hole in 24 hours, drainage is good. If it takes longer than 48 hours to drain, look for a new location.%0A%0ABesides sun and drainage, pick a location that avoids cold pockets. These cold spots usually occur on the lower section of your yard. Cold air, being heavier than warm, tends to drain down-slope to low spots, such as along washes. Here it settles, and can easily freeze the flower buds and blossoms of fruit trees. Cold air flowing down slope can also settle in areas where it meets and obstruction, such as the house or a free-standing wall. Don't plant in these cold pockets.%0A%0AJust as detrimental can be planting in excessively warm spots, such as near south or west facing walls. These areas are warmed by the winter sun and may cause fruit trees to begin flowering earlier than normal. A cold snap can then freeze these premature blossoms and eliminate the year's crop of fruit.%0A%0ANow is a good time to plant container grown fruit trees. Purchase high quality trees from a reliable nursery. This is the best way to insure that your buying the variety advertised, and that it is a healthy tree. The cost of your fruit tree will be the smallest expense in the long run. Don't cheat yourself by purchasing a lower quality tree to save money.%0A%0AIf you can't find the variety of fruit tree you want in a container, wait till this winter. A better selection can usually be had when bare-root fruit trees become available in January. These should also be planted in January. This will allow enough time for the soil to settle and new roots to develop before spring growth begins.%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 31, 1999 %0A|July 25, 2001|
7|5|Loquat|The loquat tree (Eriobotrya japonica) is what I would refer to as a multi-purpose tree. On the one hand it is a very attractive landscape tree, with dense evergreen foliage that offers both beauty and shade. On the other hand, it is a desirable fruit tree that produces tasty, somewhat tart, somewhat sweet, apricot-colored fruit.%0A%0ALoquat trees flower October through February, producing very fragrant blossoms, borne in panicles at the ends of the branches. Mature loquat trees can withstand temperatures of 10 degrees F. without serious damage. However, flowers and fruit are killed by temperatures below 27 degrees F., making them a reliable bearer only in the warmer locations around Tucson.%0A%0AFruit of the loquat are produced in clusters of 3 to 10 fruit per cluster. They are orange- yellow, somewhat fuzzy, containing one or several large brown seed. Fruit are oval, one to two inches long, with a sweet, rich, aromatic flavor. They ripen on the tree from February to April and are ready for picking when the skin turns yellow and are soft to the touch. Fruit can be eaten right off the tree or made into jam, jelly and marmalade.%0A%0AFruit quality will vary from tree to tree unless grafted varieties are selected. The best grafted variety for the desert is ‘Champagne'. It's fruit is yellow-skinned with white-fleshed, somewhat tart, and very good. Another variety ‘Gold Nugget' has deep orange fruit that are slightly acid to sweet.%0A%0ALoquat make very attractive ornamental trees. They have thick, upright branches and a very regular rounded form. Of special note are the large, coarse textured leaves. They are eight to twelve inches long, hairy when young, becoming smooth, leathery and dark gray-green when mature. The dense evergreen foliage provides pleasant shade for patios and along the south and west sides of the home. Trees mature to a height of 20 feet, making them ideal for landscapes with limited space.%0A%0ALike all trees, loquat need frequent watering during the first few months after planting. But once established they have good drought tolerant. Only occasional watering is needed to keep them attractive. Regular watering, however, is necessary to produce good fruit.%0A%0ATo encourage good fruit development on loquat, it is also necessary to occasionally prune out some branches throughout the canopy of the tree. This thinning will open the tree up to allow light in and increase fruit production. Loquat should be pruned after danger of frost has past but prior to spring bud-break. Here in Tucson that's the later part of March.%0A%0AThinning of fruit is another way to increase loquat fruit quality and size. After the fruit have formed and are about pea-size, remove half of the fruits per cluster.%0A%0ALoquat is in the rosaceae family and as such is related to plants such as pyracantha, apricot and plum. And like their relatives, loquat are susceptible to a bacterial disease known as ‘fireblight'. The name comes from the fact that diseased stems and branches appear as if scorched by fire. Branches will turn black or brown on the ends and leaves will dry out and hang on the dead branches. If fireblight infection occurs, diseased branches should be pruned off a foot below the infected portion. The diseased wood should be disposed of by placing it in a plastic trash bag and sealing the bag. Between each cut, the pruning tool should be sterilized with a 10%25 chlorox bleach solution. Although fireblight can occur on loquat, it is not commonly a problem.%0A%0AI think you'll find that loquat is a tree well worth considering for use in the home landscape. The fruit provides added attraction, and a taste you might well enjoy.%0A%0AIf you would a copy of our loquat jam, jelly, marmalade and fruit cup recipes, just send a self-addressed, stamped envelope to: Loquat Recipes, University of Arizona, Pima County Cooperative Extension, 4210 N. Campbell Ave. Tucson, Az. 85719-1109.%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 24, 1999 %0A|July 25, 2001|
8|14|Citrus Trees Fooled Into Blooming Early|	It's not spring, but you wouldn't know it by looking at the citrus trees.  Many have begun to bloom at a time they should still be resting.  So it is with a number of fruit trees.  Peach trees are covered in pink and apple trees have a noticeable white blush of flowers.  %0A%0A	All this unexpected flowering is due to an unusual combination of weather conditions that began this fall.  In a normally bone-dry October we had lots of rain.  In fact, here at the Extension Garden Center, we had just over 4 inches of rain, four times our average amount.%0A%0A	Following the rains of October came a seasonably cool November.  In response plants began their normal dormancy.  However, December turned out to be unseasonably warm, and plants that were resting began to awaken.  With warm temperatures and adequate soil moisture many plants have been fooled into thinking it's spring!  That's what all the flowering is about.  But cold temperatures are surely ahead, and those flowers, when exposed to freezing temperatures, will die.%0A%0A	If you have citrus trees flowering, don't be concerned.  Citus have opened only a small portion of their total flower buds.  In fact, citus trees produce many more blossoms than could ever turn into fruit.  Loosing some of the flowers to our next freeze will be of little consequence. And there are no practical ways to protect these blossoms from a freeze, they are much too tender.%0A%0A	As for peach, apple, plum and other types of fruit trees now blooming, a freeze will likely take most, if not all, of the flowers.  These trees will not produce a second bloom this spring.  They need the entire growing season to form new flower buds for the following spring.%0A%0A	Although blossoms cannot be protected from winter freezes, plants in general can.  Citrus trees and other cold sensitive plants can be covered during cold spells.  This is especially important for young citrus as they are more cold sensitive. %0A%0A	Cover plants with cloth, paper or frost blankets.  Do not cover plants with plastic as it will conduct the cold right to the plant.  Top on my list of supplies to have are sheets and blankets.  Never throw away old sheets.  They provide excellent cold protection when draped over frost sensitive flower beds and container plants.  Citrus and other cold sensitive varieties of trees, shrubs, cacti, and succulents can be covered as well.  %0A%0A	%0A%0A%0A	Cloth and paper provide the best insulating qualities to hold in heat.  If sheets are not available, consider purchasing frost blankets sold in garden centers and nurseries.  These are made of polypropylene that is super light weight and can be left on plants for several days without causing them harm.  Burlap is also available and insulates well.  %0A%0A	Old newspapers can be saved and used as frost blankets.  The newspaper covering should be several sheets thick to maximize cold protection.  Paper grocery bags also work well when used as "frost caps" to place over the tops of tender plants. %0A%0A	Straw covers are especially well suited for protecting vegetable, flower and herb beds.  Straw bales can be purchased at area feed stores.  A layer of straw scattered directly over plants helps to hold in the heat.  After the freeze danger has past, the straw can be pulled back and used between plants to serve as a beneficial mulch over the soil.  If cold returns the straw can simply be pulled back over the plants.  Straw bales can be purchased at local livestock feed stores.%0A%0A	When covering larger plants, such as shrubs or small trees,  it may be necessary to place a heat source under the covers.  This can be provided with a heat lamp or incandescent light bulb (60-100 watts), contained in a simple utility lamp fixture.%0A%0A	When frost covers of any type are used, it's important that they be secured properly.  Cold snaps are usually accompanied by windy conditions.   If the plant cover is not secured properly, warm air will escape.   Stones are often the most convenient items to use for tacking down covers, but you can also pin covers to the soil with loops made of heavy gauge wire.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161%0A%0A Answers to gardening questions may be obtained by phoning 626-5161 in Tucson or 648-0808 in Sahuarita. %0A%0AMaterial originally appeared in Arizona Daily Star gardening column, on  January 4, 2001%0A%0A	%0A%0A%0A%0A%0A%0A%0A |August 30, 2001|
9|8|Pomegranates Well Suited to Tucson|Pomegranates are popular fruits for desert cultivation. They are native to southeastern Europe and Asia and were grown in ancient Egypt, Babylon, India and Iran. Cultivated extensively in Spain, pomegranates moved with the missionaries into Mexico, California, and Arizona in the 16th century.%0A%0APomegranate fruits are small purplish-red berries about 2 to 5 inches in diameter. They resemble small apples, and derive their name from the French word Pome', meaning apple. Fruits have numerous seeds are each surrounded by a pink to purplish-red Judy, pulp which is the edible portion. The pulp is somewhat puckery to the taste. Although eaten fresh, pomegranate is most popular made into jelly. Fruit ripens from August to October.%0A%0ANormally a dense, bushy, deciduous shrub, 6 to 12 feet tall, the plant has slender, somewhat thorny branches. It may be trained as a small tree reaching 15 feet in height. It is also attractive espaliered against a wall. Pomegranates grow well in our alkaline desert soils and can withstand scorching heat and freezing temperatures as low as 10° F. For good fruit development, watering on a regular basis is important. Water requirements for pomegranates are about the same for citrus.%0A%0APomegranate plants are available at local nurseries and garden centers, usually in 5 gallon containers. The variety Wonderful' is the best fruiting variety. Other pomegranate varieties are available, but they are ornamental types and produce only, dry inedible berries.  %0A%0ANew plants may also be obtained by taking cuttings from known fruitful individuals. Pomegranates grown from seed do not come true-to-type. To propagate by cuttings, remove shoots 6 to 8 inches long, with the thickness of a pencil or larger. Cuttings should be taken in February or March and placed vertically in soil with the top dormant bud exposed. Dusting a rooting hormone, such as Rootone, on the cut end may speed root formation. %0A%0AWhen trained as a tree, pomegranates tend toward a bushy habit with many suckers arising from the root and crown area. Tree-type plants can be produced by allowing only one trunk to develop. Additionally suckers should be removed frequently around the main trunk(s). The goal is to produce a stocky, compact framework. To this end, plants should be cut back to 2 to 2.5 feet tall at planting. Branches should be thinned to allow 3 to 5 symmetrically spaced scaffold branches to remain at a level at least 10 inches above the ground. A year after planting, branches should be shortened to 3/5 of their length. Interfering branches and shouts should then be removed to allow 2 or 3 shoots per scaffold branch.%0A%0ALight annual pruning of established trees encourages production of good quality fruit. Dead or damaged wood should be removed in late winter. Suckering growth should be removed as it appears.%0A%0ADo not fertilize at the time of planting! Young trees should receive about 2 pounds of an8-8-8 or similar analysis fertilizer in November and March. Mature trees require 5 pounds of a similar analysis fertilizer at the same intervals. Excessive or late applications tend to delay fruit maturity and reduce color and quality.%0A%0APomegranate trees are self-fruitful. That is, they pollinate themselves. Severe fruit drop during the plant's juvenile period (3-5 years) is not uncommon. Fruit drop is aggravated by practices favoring leafy growth such as over-fertilization and excess watering. Avoid putting young plants under stressful conditions. Mature trees seem to set and hold fruit better than younger trees, so have patients!%0A%0AA free pomegranate jelly recipe can be yours by sending a self-addressed, stamped envelope to: Pomegranate Recipe, Pima County Cooperative Extension, 4210 N. Campbell Ave., Tucson, Az. 85719-1109 %0A%0A%0A--------------------------------------------------------------------------------%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%0A August 30, 1998%0A%0A|August 30, 2001|
2|13|Common Citrus Tree Problems|Citrus trees do reasonably well in the Tucson area. This, despite the fact that most types of citrus are native to regions of the world with a much milder climate than ours. Heat, drought, and intense sun combine to cause some problems we commonly see on citrus. Knowing what these problems are and how to treat them will result in healthier trees and more fruit.  %0AAt this time of year, probably the most common concern over citrus trees is the yellowing and dropping of older leaves. Fortunately, this is a normal leaf drop that all evergreen trees experience during the winter months. As leaves age, they drop off. On citrus, this usually occurs just prior to new spring growth. If you missed the recommended February fertilization, wait till May to apply fertilizer even if your tree looks anemic. Fertilizing too close to bloom can cause flowers to drop and new fruit to abort.  %0A%0AUnusually warm temperatures have prompted the early flowering of citrus trees. Often many of these flowers die. This is a natural occurrence by which the tree thins itself to carry only the fruit it can support. Some of the young fruit will also drop for the same reason. However, excessive heat and wind, common in the spring, can cause the excess flower and fruit drop. To counteract these conditions, make sure that soil is kept moist and a regular watering schedule is maintained. Let the irrigation run long enough to water the top two feet of soil. Use a soil probe or metal rod to push into the soil after watering. The probe will stop when dry soil is reached. Sometimes buried stones will be encountered. Push the soil probe in several locations to get an accurate reading. If the water hasn't penetrated the soil deep enough, water longer! %0A%0ASometimes, young leaves will be yellow. If the yellowing occurs in between the veins, while the veins remain green, it's likely an iron deficiency. This is an excellent time to apply iron to the soil around your citrus trees. With warming temperatures the iron is taken up by the trees and distributed to new growth and deficient mature leaves. Be sure to buy a chelated (water soluble) form of iron. It's more expensive, but it's the only type that works in our soil. Two excellent chelated types of iron are Sequestrene 130 and Sequestrene 330. Both work well on our alkaline, desert soils and one spring application lasts all season.  %0A%0ACurling of new leaves and whitish colored streaking in the leaves is a sign of thrip feeding. Thrips are tiny cylindrical flee-like insects that feed by scraping the surface of the leaf. As a result leaves become distorted, but remain green for the most part. Thrips feed on virtually all citrus trees. However, the damage they cause is insignificant and no control is necessary. %0A%0AAnother insect that causes concern, but little damage, is the orangedog catterpillar. The adult is the beautiful swallowtail butterfly. However, this larval stage is quite unattractive. It's brown and white coloration looks remarkably like bird droppings. Because it is a large catterpillar, about 2 inches long, it can consume many leaves. Simply pick them of by hand.  %0A%0AFruit quality is most often effected by improper variety selection, picking the fruit before it's ripe, or not meeting the cultural needs of the tree. Sour grapefruit can usually be remedied by leaving the fruit on the tree longer. Grapefruit harvested in April will be much sweeter than those harvested back in January. Granulation, or drying of the juice sacs is another problem usually caused by insufficient watering. Thick peels occur mainly as a result of over fertilization or pruning. As a rule, citrus trees should not be pruned. Holes in fruit result from the pecking of birds. Bird netting will help discourage birds. %0A%0AFinally, if a citrus tree lacks vigor, has poor fruit production and branch die-back, check near the base of the trunk. The first set of roots should be at, or near, the soil surface. If you must dig down around the trunk more than one or two inches to find the first set of roots, the tree has been planted too deeply, or soil has washed in around the trunk. In any event, this soil should be removed. A barrier should then be placed around the trunk to keep the soil from washing back. Soil in contact with the trunk will cause a slow decline and eventual death of the tree. %0A%0A%0A%0A--------------------------------------------------------------------------------%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona 626-5161. %0AMaterial originally appeared in Arizona Daily Star gardening column, on March 21, 1999 %0A%0A|July 25, 2001|
10|11|Grow Different Types of Citrus Fruits On The Same Tree|	If you grow citrus you might be interested to know that you can grow several types of citrus fruit on the same tree!  You can have the fruit of valencia oranges on your navel orange tree.  You can have the fruit of mineolla tangelos on your marsh grapefruit tree.  You can even grow the fruit of limes on your kumquat tree.  In fact, you can grow any type of citrus fruit on any other type of citrus tree.  This fruit cocktail creation is called, logically enough, a "cocktail tree".%0A%0A	Cocktail trees are formed by removing the buds from one type of citrus tree and attaching them to another type.  The resulting branches that develop will bear the type of fruit where the bud was taken from.%0A%0A	The time to "bud" citrus trees is in the spring, when the bark is "slipping".  Prior to active growth, the sap will be rising in the tree and the bark will be loose.     Buds can be removed at this time to graft onto another tree.  To determine weather the bark is "slipping" simply score the bark with a sharp knife, and see if it peels back easily.%0A%0A	Remove some one year old stems from the tree you wish to take buds from.  This might be from a friend or neighbors tree which has exceptional fruit.  Select stems that are one-quarter inch in diameter or smaller.  Cut several short pieces of stems, a foot or so in length.  These stems are referred to as budsticks.  The buds you will be removing are located at the base of each leaf, where they attach onto the budstick.%0A%0A	If you cannot preform the budding immediately, you can store the budsticks up to 3 weeks in the refrigerator.  Wrap the sticks in wet paper towels and insert the bundle in a plastic bag before placing in the refrigerator.  This will prevent them from dehydrating.%0A%0A	When your ready to bud, select a location on your tree that has branches between one-half to three-quarters inche in diameter.  This is where you will be grafting on your new buds.  It is best to choose a location that is not directly exposed to sunlight from the south or west.  %0A%0A	With a sharp knife, make a vertical cut in a smooth area on the stem.  Make the cut one and one-half inches in length and deep enough to cut through to the wood beneath the bark.  Next, make a horizontal cut one- half inch long through the bark at the bottom of your vertical cut.  When your finished you will have an inverted "T" cut.%0A%0A%0A%0A%0A	Now it's time to remove the bud for insertion into the "T" cut.  To do this select a plump dormant bud, located at the point directly above where a leaf petiole attaches on the stem. Make a horizontal cut across the budstick about one-half to three-quarters inch above the bud.  Cut the bud and a small piece of wood underneath it using a continuous motion.  The cut should begin about one-half to three-quarters inch below the bud, and should end at the horizontal cut made above the bud.  %0A%0A	Lift the chip of wood containing the bud, using the leaf petiole (leaf removed) as a handle.  This will avoid contaminating the cut side of the bud chip with soaps or oils from your fingers. %0A%0A	Next, carefully peal back the bark of the "T" cut just enough to slide in bud chip in.  Push the bud chip down carefully from the top of the "T' , towards the bottom.  Slide it far enough down so that the bark flaps hold the bud tightly in the pocket.  Be careful not to locate the bud upside-down.  Orient the bud the same direction on it's new stem as it was on the stem or it was taken from. %0A%0A	Finally, wrap the entire cut, above and below the bud with teflon tape.  Wrap so that only the bud and leaf petiole are peeking out.  This will keep the cut , the bud, and surrounding sapwood from drying out while it heals.  %0A%0A	In a few weeks, remove the tape.  If the budding was successful, the bud will form into a new shoot.  If the bud remains alive but does not grow, try bending the stem over just above the inserted bud and tieing it over.  %0A%0A	Budding is both an art and a science.  You may want to try grafting several buds, hoping that one will take and grow.  Don't be discouraged by early failures.  As you practice, your success rate will increase.%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 March 11, 2001|August 30, 2001|
11|9|It's Time To Fertilize Citrus|With the approach of spring, citrus trees will soon come into full bloom.  To promote this flowering and the subsequent development of fruit, it's important to fertilize citrus trees now.%0A%0A	Citrus trees need both nitrogen and phosphorous to grow properly.  You can supply this by using a fertilizer such as ammonium phosphate (16-20-0), or you can use a similar analysis specially prepared citrus tree fertilizer.%0A%0A	Young trees (1 to 2 years after planting) will require about one-half pound of fertilizer.  Small trees (2 to 3 years after planting) will require about three-quarters pound.  Mid-sized, small trees (3 to 4 years after planting) will require about a pound and one-half.  Small adult trees (4 to 5 years after planting) will require about two pounds of fertilizer.  Mid-sized adult trees (5 to 6 years after planting) will require about two and one-half pounds.  Large-sized adult trees (more than 6 years after planting) will require about three pounds of fertilizer.%0A%0A	Spread the fertilizer evenly under the tree, starting near the trunk and going out several feet beyond the branch ends.  After spreading the fertilizer, lightly scratch it into the top quarter inch of soil using a garden rake.  Next, water the fertilizer in slowly.  I like to use a soaker hose for watering.  If you have basin watering, simply fill the basin and allow the water to soak in.%0A%0A	Citrus trees generally need to be fertilized three times during the year; in February, May and August.  Apply the same amount of fertilizer with each application.  A caution however, do not over-fertilize!  Citrus trees that get too much fertilizer will develop thick peels on fruit.  If your citrus tree is growing vigorously and has dark green leaves, cut back on the recommended fertilizer amounts.  You may want to skip one of the recommended all together if the tree appears healthy.%0A	%0A	At this time of year, probably the most common concern over citrus trees is the yellowing and dropping of older leaves.  Fortunately, this is a normal leaf drop that all evergreen trees experience during the winter months.  As leaves age, they drop off.  On citrus, this usually occurs just prior to new spring growth.  %0A%0A	It is normal for new leaf growth on citrus to be yellowish-green in color.  However, if over time these new leaves fail to turn dark green, there may be a need to add iron to the soil.  Don't use just any iron product.  I recommend chelated iron.  It is more expensive than other forms but it is the only type that works in our alkaline desert soils.  Two excellent chelated types of iron are Sequestrene 138, also sold as Ferrione 138.%0A	Curling of new leaves and whitish colored streaking in the leaves is a sign of thrip feeding.  Thrips are tiny cylindrical flee-like insects that feed by scraping the surface of the leaf.  As a result leaves become distorted, but remain green for the most part. Thrips feed on virtually all citrus trees.  However, the damage they cause is insignificant and no control is necessary.%0A%0A	Proper fertilization of citrus should help maintain the trees vigor and fruiting.  If your citrus tree lacks vigor, has poor fruit production and branch die-back, check at the base of the trunk.  The first set of roots should be at, or near, the soil surface.  If you must dig down around the trunk more than one or two inches to find the first set of roots, the tree has been planted too deeply, or soil has washed in around the trunk.  In any event, this soil should be removed. A barrier should then be placed around the trunk to keep the soil from washing back.  Soil in contact with the trunk will cause a slow decline and eventual death of the tree.%0A%0AFinally, don't miss the Orchid & Flower Show today at Tucson Mall.  The show is presented by the Orchid Society of Southern Arizona.%0A%0A Answers to gardening questions may be obtained by phoning 626-5161 in Tucson or 648-0808 in Green Valley. %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  %0AFebruary 18, 2001%0A|August 30, 2001|
13|15|Fruits of The Desert|	Well, maybe we can't grow apples like Washington State or peaches like Georgia, but with the right varieties, good fruit can be grown here in the desert.  The key to success is choosing varieties of fruit that have a low chilling requirement.%0A%0A	Deciduous fruit trees; apples, peaches, apricots, pears, and plums need a minimum amount of cold during the winter to properly grow and produce fruit.  Many varieties of fruit trees need more cold than we typically receive here in Tucson.  The ones that require the least amount of cold temperatures (low chill) are the ones we can grow.  They include; ‘Anna' or ‘Dorsett Golden' apple; ‘Desert Gold' or ‘Flordaprince' peach; ‘Orient', ‘Floridahome' or ‘LeConte' pear; ‘Katy', ‘Gold Kist', or ‘Castlebrite' apricot, and ‘Santa Rosa' or ‘Satsuma' Japanese plum.%0A%0A	For fruit to form, pollination of the flowers must occur.  Some fruit trees will pollinate themselves and are termed self-fruitful.  Apricots are self-fruitful, so only one tree needs to be planted to produce fruit.  Other fruit trees will not pollinate themselves and are termed self-unfruitful.  Therefore two varieties must be planted for fruit set to occur.  This is called cross-pollination.   Peaches, and pears are self-unfruitful and require cross-pollination.  Apples and Japanese plums are also generally self-unfruitful, but ‘Anna' apple and ‘Santa Rosa' plum will set fruit fairly well without cross-pollination.%0A%0A	Choosing the right location to grow a fruit tree around your home is another important consideration.  Fruit trees need full sun to grow and produce fruit.  They also need a well drained soil.  To check drainage, dig a hole about the size of a five gallon container in the location you intend to plant your tree.  Fill it with water, and after the water drains out, fill it again.  If after the second filling, water drains out of the hole in 24 hours, drainage is good.  If it takes longer than 48 hours to drain, look for a new location.%0A%0A	Besides sun and drainage, pick a location that avoids cold pockets.  These cold spots usually occur on the lower section of your yard.  Cold air, being heavier than warm, tends to drain down-slope to low spots, such as along washes.  Here it settles, and can easily freeze the flower buds and blossoms of fruit trees.  Cold air flowing down slope can also settle in areas where it meets and obstruction, such as the house or a free-standing wall.  Don't plant in these cold pockets.  %0A%0A	Just as detrimental can be planting in excessively warm spots, such as near south or west facing walls.  These areas are warmed by the winter sun and may cause fruit trees to begin flowering earlier than normal.  A cold snap can then freeze these premature blossoms and eliminate the year's crop of fruit.     %0A%0A	Now is a good time to plant container grown fruit trees.  Purchase high quality trees from a reliable nursery.  This is the best way to insure that your buying the variety advertised, and that it is a healthy tree.  The cost of your fruit tree will be the smallest expense in the long run.  Don't cheat yourself by purchasing a lower quality tree to save money.%0A%0A	If you can't find the variety of fruit tree you want in a container, wait till this winter.  A better selection can usually be had when bare-root fruit trees become available in January.  These should also be planted in January.  This will allow enough time for the soil to settle and new roots to develop before spring growth begins.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0A%0AThe Extension Center is located at 4210 N. Campbell Avenue.  Answers to gardening questions may be obtained by phoning the Extension Center Plant Clinic, weekdays for 9:30 a.m. to 3:30 p.m. at 626-5161.  Green Valley residents may call our Sahuarita satellite office Mondays, Wednesdays and Fridays from 9:00 a.m. to 1:00 p.m.%0A|October 31, 1999|
14|16|Fruiting Fig Well Suited to Desert Landscapes|	The fruiting fig (Ficus carica) is an excellent fruit and ornamental tree for desert landscapes.  That's because many of the common figs, including the ones we grow here in Tucson are native to hot, dry regions of the Mediterranean. %0A%0A	Fig trees have attractive large, deeply-lobed leaves that are somewhat tropical in appearance, although trees are to around 15 degrees.   The rounded canopy of foliage is supported by attractive thick, gray-barked, spreading branches.  Fig trees can grow to a height of 20 feet with equal or greater spread, but can be kept pruned to under 10 feet.  Fig trees are deciduous, dropping their leaves in late Fall and leafing out again in early spring.  Fruits are dark brown to purple and pear-shaped. %0A%0A	Fruits can be eaten fresh off the tree, dried, or processed.  In California figs are commercially produced and processed into paste for use in such products as fig bars or are dried and packaged for direct consumption.%0A%0A	Typically, two crops of figs are produced per season.  The first crop develops in the spring and ripens in June.  The second appears in late summer and may continue into the fall.  But don't look for flowers on your fig tree!  Unlike other tree fruits, fig trees have no blossoms on their branches.  The flowers actually develop inside the fruit.  These many tiny flowers produce the crunchy little seeds with give figs their unique texture.%0A%0A	The varieties most successfully grown here in Tucson are the ‘Brown Turkey' and ‘Black Mission' fig.  Both are common fig varieties that do not require pollination to produce mature fruit.  %0A%0A	Brown Turkey produces medium-sized, flavorful fruit with mahogany brown to purple skin.  The fruit is best eaten fresh and is not good for canning or drying.  For best fruiting, Brown Turkey requires heavy annual pruning to encourage maximum fruit production.  Prune in the Winter when the tree is dormant and it is easy to see the overall form.%0A%0A	Black Mission produces larger, purplish-black fruit with excellent flavor, that can be eaten fresh, dried or canned.  Only light pruning is generally recommended to provide a uniform shape and encourage good fruit production.  Heavier pruning may be done to control size.  %0A%0A	Pruning should include the cutting back of long branches to the desired length.  Inward growing branches, water sprouts and crossing branches should also be removed.  Keeping the center of the tree open to allow light penetration will encourage better fruiting.  However, do not prune heavily in late spring or summer.  Pruning then will expose the bark to strong sunlight and result in sunburn injury to the trunk and main branches. %0A%0A	Because of their pliable branches, fig trees are easily trained as ‘espaliers'.  In this method, the tree is planted against the wall and branches are trained to grow fanned out in a flat pattern against the surface.  Branches growing out, rather than against the wall are kept pruned off.  Brown Turkey is especially suited for espalier culture.  East or south facing walls or fences are preferred for planting.  Trees planted along west facing walls receive too much sun and heat to grow well.  North facing walls do not provide the amount of sunlight necessary for fruiting.%0A%0A	Fig trees require good drainage and regular irrigation.  During normal summer conditions, fig trees will need to be watered every 5 to 7 days.  During extremely hot and dry conditions, watering may need to be increased.  In the winter months, watering once every two weeks should suffice.  If a tree is not getting enough water, the leaves will turn yellow and drop off.  But natural yellowing and leaf drop will also occur when the tree is going winter dormant, usually in December. %0A%0A	Fertilization is generally not required, unless new growth is less than one foot.  When needed, apply two pounds of ammonium sulfate or similar fertilizer per tree in March and again in July.%0A%0A	Finally, as with any fruit tree, keep in mind that figs can be messy.  Dropping fruit attracts bees and other insects and can stain walks and patios, so choose a planting location carefully.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |September 9, 2001|
15|17|October Ideal For Planting Citrus Trees|	Now that the weather is finally becoming more seasonable, conditions are just right for planting all types of citrus trees.  Cool nights and warm days provide ideal growing conditions.  Most importantly, new roots, the foundation of healthy citrus trees, are encouraged to spread out into the warm October soil.%0A%0A	When selecting a citrus tree, first take into account it's cold hardiness.  Some types of citrus will not grow in the colder parts of town.  The most cold hardy of citrus are the mandarins, which include tangelos and tangerines.  Next in cold hardiness are the grapefruits and oranges. Lemons and limes are the least cold hardy.  Consider limes only if you live in a location that rarely experiences freezing temperatures.  You can also grow a lime tree in a large container and move it to a protected spot during winter cold snaps.  %0A%0A	Mandarin type citrus include tangerines and are noted for their distinctive flavor and ease of pealing.  Clementine, Fairchild and Kinnow are the best tangerines for Tucson. Mandarins also include citrus called tangelos.  Tangelos are hybrids resulting form the cross of tangerine and grapefruit.  They are very sweet and have the flavor of both tangerine and orange.  Mineolla is an excellent tangelo and one I highly recommend!  The juicy sweetness of the fruit and distinctive bell-shape give Mineolla the well-deserved common name "Honey Bell".  If you have room for only one citrus tree, this should be the one! %0A%0A	Grapefruit are divided into two categories: white and pigmented.   People prefer the pigmented types because of their red-blushed skin and pink to red internal fruit.   Both Redblush (also called Ruby Red), and Reo Red are excellent pigmented grapefruit varieties.  Rio Red has the deepest red internal color.  Marsh is the preferred variety of white grapefruit.  Although whites are not as popular, Marsh is just as sweet as the red varieties.  All grapefruit will be their sweetest if left on the tree till March or April.%0A%0A	Oranges are by far the most popular of all citrus.  The type you choose to grow depends on when you want it to ripen and what you want to use it for.  Early-season oranges for Tucson include the group called "Arizona Sweets".  These are the varieties Hamlin, Diller and Trovita.  They have sweet fruit good for eating fresh or juicing and ripen in January and February. %0A%0A	Navel is a mid-season orange, ripening from November through March.  It is best for eating fresh. For juicing the best is Valencia. The fruit of Valencia mature in late-season, from February through May.  Blood oranges, such as Moro and Ruby, are also excellent for juicing.  As the name implies, their juice is a beautiful burgundy color.  %0A%0A	Everyone enjoys lemons, but if you grow one, plan on supplying fruit for your whole neighborhood.  Lemons are very prolific producers!   Eureka and Lisbon are good varieties for Tucson.  Lisbon, however is probably the better choice because of it's greater frost tolerance.  Myer and "Improved" Myer lemons are actually a cross between a sweet orange and lemon.  Their sweeter character is desirable, but they're illegal to purchase here in Arizona because they harbor a deadly virus of citrus called "Tristeza".  %0A%0A	Limes are more challenging to grow here in Tucson than other citrus because of their extreme frost sensitivity.  The kind we grow are the Mexican limes.  If your from  Florida or the Carribean they're referred to as  Key limes.  Great for making pies and flavoring drinks, they are almost always harvested green, but mature yellow limes are just as good. %0A%0A	Regardless of the type of citrus you choose, all require good drainage.  You can preform a drainage test in your yard prior to planting to determine the best location for your tree.%0A%0A	Dig a hole 12 inches wide and 2 feet deep.  Fill the hole with water.  After the water drains out, fill it again.  If the water drains out in less than 24 hours, the drainage is excellent.  If it drains in less than 48 hours, it is acceptable.  If it takes longer than 48 hours, forget planting citrus!%0A	%0A	Finally, when planting your tree it's very important that the top of the root-ball be level with or slightly higher than the surrounding soil.  Dig a shallow, wide hole and backfill with existing soil.  Do not try improving the soil by adding compost, manure or top soil.  Improved "pot in the ground" soil will constrict root growth.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |October 7, 2001|
5|18|Correcting Summer Citrus Tree Problems|%0A	Citrus are favorite fruits here in Tucson and other low desert areas of Arizona.  They are well adapted to the hot conditions, but like most plants with the intense heat of summer, problems can develop.%0A%0A	The most common problem symptom seen at this time of year is curling or rolling of the leaves.  This usually develops first on the newer or outermost leaves.  It can be caused by insufficient water, or insect feeding.  If the curling leaves seem to be concentrated on the south or west side of the tree, then the problem is likely insufficient water.  If the curled leaves are in various locations around the tree, the problem is likely insect damage.%0A%0A	The feeding of sucking insects such as aphids and thrips cause leaf curl on citrus.  Aphid are small green or yellowish green insects.  Their presence causes leaves to curl and yellow.  They also secrete a clear sticky substance called "honeydew" which creates a varnish-like appearance on leaves.  %0A%0A	Other common insects attacking citrus are thrips.  These tiny flea-like pests feed on developing leaf buds of citrus, by tearing and slurping up the juices.  As a result, mature leaves are cupped or curled and marked with distinctive whitish lines.  %0A%0A	Be in caused by thrips or aphids, the resulting curling of leaves is mealy cosmetic and causes no actual harm to the tree.  No control is possible for thrips; but as they appear, aphids can be knocked off the leaves with a strong spray of water.%0A%0A	Leaf curling from insufficient water is a problem that must be dealt with!   Water the tree deeply and from the trunk out to at least the edge of the branches.  If you have only a few drip emitters under the tree, then add some more.   A mature citrus tree is likely to need ten or more drip emitters.  If your basin irrigating you tree, make sure the basin extends out to the edge of the branches.  Fill the basin with three inches of water.  This will soak the soil down to the required 3 foot depth.  If you problem is a lack of emitters and you can't add more for some time, then water temporarily with a soaker hose.  Wrap the hose around the tree, spiraling it out from the trunk to the branch ends.  Then turn the water on low and let it run for several hours. If the soil is very hard, it may be necessary to water the better part of a day to get it to soak in.%0A%0A	Sometimes citrus leaves will become sun-scorched.  If some leaves are curled and others have bleached-out patches of yellow, sun-scorch is occurring.  Shading the citrus will help temporarily.  Increasing the frequency of watering may also help.  Shade cloth can be purchased at local garden centers.  It should be positioned to screen out the mid-day and afternoon sun.  When cloud cover from the monsoons arrive, shading can be curtailed.%0A%0A%0A%0A%0A	Yellowing of leaves on citrus during the summer can also be caused by a lack of certain nutrients.  Leaves may turn yellow from insufficient levels of nitrogen, iron or zinc.  A deficency in nitrogen causes an overall yellowing of the leaves.  If iron is lacking, most of the leaf yellowing will be on the outer and younger leaves.  Many of the individual leaves will show a condition called chlorosis.  Leaf veins will remain green, but the areas between the veins will turn yellow.  This creates a fish-bone pattern in the leaf.  Zinc deficiency also causes chlorosis, but unlike iron in which leaf veins are narrowly green, the veins of zinc deficient citrus are broadly green set against a background of yellow.%0A%0A	A nitrogen deficiency can be easily corrected with the addition of ammonium sulfate or other nitrogen containing fertilizer.  Iron can be applied to the soil using a chelated form of iron available at local garden centers.  In any case, after applying nutrients, water them into the soil thoroughly.%0A%0A	When the monsoon rains arrive, citrus that are improperly planted or are in poorly drained soils can be susceptible to fungal diseases.  The most common is foot rot caused by a water mold fungi called phytophora.  Foot rot is so named because it attacks the base of the trunk.  It causes bleeding lesions that weep sap.  This sap forms into gummy patches. When the trunk is partially girdled by foot rot, leaves turn yellow as if nitrogen deficient.  Eventually the tree will die.%0A%0A	To prevent foot rot, make sure that soil is not in contact with the base of the trunk.  Planting citrus too deep results in soil coming in contact with the trunk.  Pull this soil back and keep it back by using an edging product.  Finally, be careful not to over water during periods of abundant summer rain.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161|June 30, 2002|
12|19|It's Time to Fertilize Citrus|%0A%0A%0A	With the approach of spring, citrus trees will soon come into full bloom.  To promote this flowering and the subsequent development of fruit, it's important to fertilize citrus trees now.%0A%0A	Citrus trees need both nitrogen and phosphorous to grow properly.  You can supply this by using a fertilizer such as ammonium phosphate (16-20-0), or you can use a similar analysis specially prepared citrus tree fertilizer.%0A%0A	Young trees (1 to 2 years after planting) will require about one-half pound of fertilizer.  %0A%0A	Small trees (2 to 3 years after planting) will require about three-quarters pound.  %0A%0A	Mid-sized small trees (3 to 4 years after planting) will require about a pound and one-half.  %0A%0A	Small adult trees (4 to 5 years after planting) will require about two pounds of fertilizer.  %0A%0A	Mid-sized adult trees (5 to 6 years after planting) will require about two and one-half pounds.  %0A%0A	Large-sized adult trees (more than 6 years after planting) will require about three pounds of fertilizer.%0A%0A	Spread the fertilizer evenly under the tree, starting near the trunk and going out several feet beyond the branch ends.  After spreading the fertilizer, lightly scratch it into the top quarter inch of soil using a garden rake.  Next, water the fertilizer in slowly.  I like to use a soaker hose for watering.  If you have basin watering, simply fill the basin and allow the water to soak in.%0A%0A	Citrus trees generally need to be fertilized three times during the year; in February, May and August.  Apply the same amount of fertilizer with each application.  A caution however, do not over-fertilize!  Citrus trees that get too much fertilizer will develop thick peels on fruit.  If your citrus tree is growing vigorously and has dark green leaves, cut back on the recommended fertilizer amounts.  You may want to skip one of the recommended all together if the tree appears healthy.%0A	%0A	At this time of year, probably the most common concern over citrus trees is the yellowing and dropping of older leaves.  Fortunately, this is a normal leaf drop that all evergreen trees experience during the winter months.  As leaves age, they drop off.  On citrus, this usually occurs just prior to new spring growth.  %0A%0A%0A%0A	It is normal for new leaf growth on citrus to be yellowish-green in color.  However, if over time these new leaves fail to turn dark green, there may be a need to add iron to the soil.  Don't use just any iron product.  I recommend chelated iron.  It is more expensive than other forms but it is the only type that works in our alkaline desert soils.  Two excellent chelated types of iron are Sequestrene 138, also sold as Ferrione 138.%0A%0A	Curling of new leaves and whitish colored streaking in the leaves is a sign of thrip feeding.  Thrips are tiny cylindrical flee-like insects that feed by scraping the surface of the leaf.  As a result leaves become distorted, but remain green for the most part. Thrips feed on virtually all citrus trees.  However, the damage they cause is insignificant and no control is necessary.%0A%0A	Proper fertilization of citrus should help maintain the trees vigor and fruiting.  If your citrus tree lacks vigor, has poor fruit production and branch die-back, check at the base of the trunk.  The first set of roots should be at, or near, the soil surface.  If you must dig down around the trunk more than one or two inches to find the first set of roots, the tree has been planted too deeply, or soil has washed in around the trunk.  In any event, this soil should be removed. A barrier should then be placed around the trunk to keep the soil from washing back.  Soil in contact with the trunk will cause a slow decline and eventual death of the tree.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0A|February 16, 2003|
16|20|It's Citrus Planting Time|	Now that the danger of frost has past, it's time to plant citrus!  Garden Centers are stocked-up, and ready with a wide variety of the most popular home citrus varieties. %0A%0A	If you have room for only one citrus tree in your yard, then make it a Mineola tangelo, commonly referred to as the "honey bell" for it's honey-sweet and unusual bell-shaped fruit.%0AAlthough similar to an orange, Mineola Tangelo is actually a cross between Dancy mandarin and Duncan grapefruit. The combination gives Mineola a distinctly rich, sweet flavor, excellent for eating or juicing.%0A%0A	If you have room for a second tree, make it an orange.  Oranges are by far the most popular citrus, and we have an excellent choice of varieties for growing in Tucson.  Arizona Sweets are a group of oranges well-suited to the low and mid-elevation desert locals.  All are good, but there are subtle differences between them.  Hamlin and Marrs are early season Arizona Sweets, ripening from November through January.   Both are excellent for juicing.  Diller and Trovita are mid-season Sweets, ripening from December through February. They're great for eating or juicing. %0A%0A	If you want a late-season orange, then Valencia is for you.  This is the world's premiere juicing orange, but it is also very good to eat!  In addition, Valencia will keep on the tree when ripe for many months, becoming sweeter as time goes on.  %0A%0A	If you have very limited space, consider planting a dwarf or semi-dwarf citrus.   These trees take up as little as half the space of a full-sized citrus.  Dwarfing is accomplished by budding a citrus hybrid variety on the roots of another type of citrus with dwarfing properties.  For a semi-dwarf tree, about one-third smaller than the standard tree, look for the citrus you want growing on C-35 Citrange rootstock.  If you want a tree half as large as the standard, choose Flying Dragon rootstock.  Most citrus sold have tags listing both the hybrid budded top and the rootstock. %0A%0A	Purchase citrus from a reputable garden center or nursery.  The most vigorous and easiest to transplant trees are those sold in 5 or 15 gallon containers.  Small trees establish and grow faster than larger ones sold in 24 or 36 inch boxes.  Quality citrus trees can be costly,  but it's better to pay the price than save money and end up with a weak, inferior tree.%0A%0A	Citrus should be planted in well-drained soil.  To test the location where you intend to plant, dig a hole 12 inches wide and 18 inches deep.  Fill the hole with water and allow it to drain out.  Fill it again, and time how long it takes for that water to drain out.  If it takes longer than 48 hours, choose a different location for planting.  If a caliche hardpan is blocking drainage, it should be removed. %0A%0A%0A%0A	It is critical to plant citrus no deeper than they were growing in the pot.  Citrus trees cannot tolerate soil contacting the base of their trunks.  For this reason, dig the hole no deeper than the height of the root ball.  In fact, it's better to dig the hole a little less deep so that the top of the root ball stands slightly above ground.%0A%0A	Dig the planting hole a foot or so wider than the root ball.  Loosen the soil and remove the larger rocks will encourage the roots to grow out into the native soil.  And contrary to popular belief, the planting soil should not be amended with organic matter such as compost, peat or manure.  The healthiest and strongest citrus trees are those whose roots grow out into the native soil.  Filling the hole with "good stuff" actually restricts normal root growth. %0A%0A	After planting, water the tree daily for the first two or three weeks.  After that, water two or three times weekly through October.  When cooler weather arrives in November, reduce the frequency of watering to every 7 to 10 days.%0A%0A	Finally, you may apply a small amount of fertilizer a month or so after planting and again in August to maintain tree vigor.   Apply one-quarter cup (5 gallon trees)  to one-half cup (15 gallon trees) of ammonium sulfate (21-0-0) or citrus fertilizer per tree.  Scatter the fertilizer near the near the base of the tree and then water it into the soil.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0A%0A|March 23, 2003|
17|21|Growing a Pineapple Is Novel and it May Produce Fruit|%0A	If you want to grow a tropical fruit and impress friends and relatives with your gardening prowess, try a pineapple.  It's really not difficult to grow a pineapple plant, but to have it produce a fruit takes some know-how and a little bit of luck. %0A%0A	Pineapples are the most cold-tolerant of all the tropical fruits.  However, damage to the leaves will occur at about 28 degrees.  This means, planting them in a protected location and planning to cover them up on cold winter nights.  Because pineapples really don't like our desert soils the best way to grow them is in a container.  That way they'll get good drainage and you can use a potting soil that has the acidic quality they prefer.  It also makes cold protection easier as you can just move the container to a protected location on frosty nights.%0A%0A	Pineapples can easily be started from the fruit you purchase in the grocery store.  Choose a healthy pineapple with a robust set of leaves sprouting out the top.  The small leaves at the very top should be well-attached.  Give them a tug.  If they pull out easily, move on to another pineapple.%0A%0A	At home, cut the top (the cluster of leaves) off at the point where the leaves meet the fruit.  Next, pull off the lower, outer leaves to reveal the stem.  Do not allow any of the fruit pulp to remain attached to the leaves.  %0A%0A	There are two ways to root your pineapple top.  One way is to place it in water and after roots form, plant it in a container with soil.  The other method is to pot it and allow the roots to form directly into the soil.  Either method is satisfactory.%0A%0A	If you use the water method, remove the lowest leaves until 5 to 10 larger leaves remain, along with the many smaller leaves hidden inside.  This should expose one-half to one inch of stem.  Place the stem in a drinking glass with water, so that the bottom half-inch of the stem is submerged.  The base of the leaves themselves should be out of the water.  Place the shoot in a bright spot indoors; but out of direct sunlight.  Maintain the water level so that the base of the stem is kept submerged.  Roots should begin to form within the next few weeks.  Then the top can be planted in a container in well-drained potting soil.%0A%0A	If you choose to plant you pineapple top directly in soil, let the cut stem dry for a few days before planting.  This curing process will prevent the stem from rotting once placed in soil.  Remove enough of the lower leaves so that the amount of stem stuck into the soil is sufficient to keep the top from falling over.  Make sure the potting soil you use is well-drained. You can select just about any potting soil, but always add perlite to lighten the mix.  I recommend one part perlite to three parts potting soil, mixed thoroughly together.%0A%0A	Water at the time of planting and then often enough to keep the soil evenly moist.  Use a moisture meter for best results.  Locate the plant in a bright location.  You can set it outdoors, but keep it out of direct sunlight and carefully attend to watering.%0A%0A	Once the top begins putting out new leaves, apply a water-soluble plant food, continuing on a monthly basis.  Any general-purpose house plant fertilizer will do.  Apply some of the fertilizer to the cup-shaped crown of the plant and some to the soil.  After the roots are well-formed (usually about 6 months), continue applying fertilizer to the soil but not to the crown, as the latter could damage the developing bud.%0A%0A	Now, as to getting a pineapple to form; have patients.  It could take 2 to 3 years for flowering to occur naturally.  There is a way to speed up the process.  Pineapples can be forced into flowering early if the plant is strong and vigorous.  To do this, place pieces of an apple around the base of the plant and cover the plant with a large clear plastic bag.  A dry cleaning bag works well. %0A%0A	The pieces of apple give off a gas called ethylene that promotes ripening and, in the case of pineapple, flowering.  Try this when the weather begins to warm next spring.  Leave the bag on for a week, then remove it.  If flowering does not occur in three or four weeks, try again in the Summer.  If flowering occurs, the developing fruit will take another 6 months or so to mature.  If you don't at first succeed in getting a pineapple, try, try again.  Some of the fun is in the effort, and if you're successful your reward will be even "sweeter"!%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161.%0A%0A%0A%0A%0A%0A%0A%0A%0A%0A	%0A%0A|June 15, 2003|
18|22|New Years Resolution for Gardeners -  Grow Tropical Fruit|Why not start the new year off with warm thoughts of Summer and the opportunities that lay ahead in the coming year.  Speaking of opportunities, I have a suggestion for all those gardeners looking for something adventurous to do in the new year.  Why not grow tropical fruits!%0A%0A	Sounds absurd; exotic fruits in Tucson (Chinese Jujube excluded), but you can grow many successfully as long as their grown in containers!  When frosty weather arrives you simply roll or dolly them to a protected location- outdoors or bring them into Arizona Room till warmer weather returns.  Actually any roomy spot indoors will do.%0A%0A	Of course, the best tropical fruits for containers are the ones which are naturally smaller growing.  Many of these fruits grow in shrub or small tree size, and lend themselves to confined container culture.  Here are a list of some interesting ones to try:%0A%0ABarbados Cherry - A large, densely branched shrub or small tree which can be pruned to a central trunk.  Native to the West Indies, Barbados Cherry produces shiny light to deep green ovate leaves and soft, juicy ,thin-skinned, three-lobed fruit that are light to deep crimson when mature.  The fruit has a sweet-tart taste and just one is high enough in vitamin C to meet the daily adult requirements.%0A%0ACarambola - Star fruits, named because of their star-shape when sliced, are widely sold in grocery stores and have a distinctive citrus flavor.  Grown commercially in Hawaii and South Florida, Carambola is a native to Southeast Asia.  Fruit are 2 to 6 inches in length, are light to dark yellow when ripe, and are a good source of potassium.  The varieties ‘Golden Star' and ‘Arkin' are self-pollinating.%0A%0ACherry of the Rio Grande - The fruit of this plant, as the name implies, tastes somewhat like cherries and can be eaten fresh or used for making jams and jellies. Fruit are oblong, about an inch in length, and orange ripening to dark red or purple.  Like other Eugenia species it is an attractive plant with dark green, evergreen leaves.%0A%0AJaboticaba - This small bushy tree or small shrub has evergreen foliage and multicolored bark. It's slow growth makes it ideal for containers.  A native of Brazil, Jaboticaba produces grape-like fruit, with a thick, tough dark-maroon color.  Unlike most other fruit, these grow directly out of the trunk and larger branches, singly or in clusters from the ground up.  Under the skin is a whitish, gelatinous pulp with a pleasant grape-like flavor.  The skin is usually discarded, and only the pulp is eaten.%0A%0AMiracle Fruit - This evergreen shrub grows to a height of 5 feet, under cultivation, and produces small bright red berries.  Although not sweet itself, when the fleshy pulp is savored and allowed to coat the taste buds, everything eaten after that, even lemons, will taste sweet!  The effects last some 30 minutes or more.  You can really surprise your friends with this one.%0A%0AMonstera - This plant is very similar to spreading philodendron in size and appearance.  However the leaves are more rounded in form.  The plant produces a flower cone that develops seeds and a sweet pulp that tastes like a cross between banana and pineapple.  You won't get much to eat from the fruit of Monstera deliciosa, but what you do get is truly delicious.   %0A%0ASurinam Cherry - This evergreen shrub has ovate leaves which are wine colored when young, turning to a dark glossy-green at maturity.  The fruits are attractive light red to nearly black, They have an unusual ribbed shape, about the size of a bing cherry.  The flesh is orangish and has an aromatic, sweet and somewhat cherry-like, good for jams and jellies.  The plant can be kept cut back on a regular basis and still produce fruit.%0A%0A	Other exotic fruits recommended for pot culture include; Banana, Carissa, Guava, Passion Fruit and Pineapple.  In next weeks column I will discuss the growing of tropical fruits in containers and provide some additional references and resources on the subject.  %0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0A|January 4, 2004|
19|23|Citrus Tree Die-back|The recent cold has frozen the outer growth of many citrus trees here in Tucson.  In most cases only the leaves were killed, but some stems might also have frozen.  But this damage is temporary and will not effect the overall health of the trees.  However, a general die-back of citrus stems and branches is a serious problem and indicates a problem with either the trunk of the tree or the root system.%0A%0A	Damage to the trunk of a citrus tree can occur when soil comes in contact with the base of the trunk.  This can happen if the tree was planted too deep, or settled in the planting hole.  Citrus are very sensitive to having any soil against their trunks.  Even an inch of soil covering the trunk is enough to damage the sapwood and result in a stunting and eventual die-back of the branches.  If this soil is not removed, over time, the tree will likely die.  %0A%0A	Citrus that are watered by basin irrigation are also likely to have soil that has accumulated around the trunk.  It's a good idea to check the trunk two or three times during the year and to pull back any build-up of soil.  You should be able to see where the first set of roots come out from the base of the trunk.%0A%0A	Both over-watering and under-watering are also causes of die-back in citrus.  Over-watering keeps the soil too wet, blocking soil pores and preventing oxygen from passing into the soil and down to the roots.  Without adequate oxygen, and in the presence of water, fungus present in the soil can attack and kill roots.  This condition is known as root rot.  As the roots die, a corresponding death of the branches occurs, starting with the outermost stems and moving inward.%0A%0A	Under-watering can also cause die-back.  When the tree is not getting enough water, those stems and branches farthest from the roots are the first to die.  A rolling of the leaves, similar to the rolling of a cigar, is the first sign of inadequate watering.%0A%0A	To avoid problems of over or under-watering follow proper citrus watering practices.  Established trees, those planted longer than one year, should be watered once a week during the warm months (April - October) and once every two weeks during the cool months (November- March).  But critical to this schedule is deep watering.  The tree should be watered long enough or with enough water to soak the soil to a depth of 3 feet.  To do this, use a metal rod, such as a five foot long piece of re-bar which can be purchased at hardware or building supply stores.  The rod can be pushed down into moist soil, but will stop when dry soil is hit.  Because of the likelihood of hitting buried rocks, push the probe down in several locations to get an accurate reading.%0A%0A%0A%0A%0A%0A	Over time salts building up in the soil can also cause citrus stems and branches to die.  Salts naturally occur in desert soils, but salts are also added by fertilizing and through irrigation.  The amount of salt in irrigation water is small, but without an occasional flushing, these salts can accumulate to harmful levels.  %0A%0A	To prevent or to correct a salt buildup, citrus trees should be watered heavily at least twice yearly.  A heavier watering than normal will help dissolve excess salts and flush them down below the roots.  The best way to accomplish this is to coil a soaker hose under the tree and let the water slowly seep out for 10 to 12 hours.  The best times of year to do this heavy watering is during a rainy period in the Winter and again during the Summer Monsoon season.%0A%0A	Finally, citrus trees do have a normal life expectancy.  Under good conditions and in milder climates, citrus trees may live to 50 years or more.  But here in the desert that life expectancy is considerably shorter.  A 30 year old citrus tree is considered old and at about that age, it will begin to gradually decline with a dying back of stems and branches.  At that point, it's best to plant a new, vigorous citrus tree to replace it.  %0A%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |February 1, 2004|
20|24|Blackberries Provide Abundant Crop for Tucson Gardeners|It's a shame that we can't grow raspberries here in Tucson, however we can grow the next best bramble, blackberries!  Texas A&M has developed several varieties that grow well in our desert environment, producing an abundance of large, sweet berries. %0A%0A	Blackberries are perennial plants, but each shoot is biennial.  Each shoot only survives for 2 years.  During the first year a shoot, referred to as a cane, produces leaves only.  During the second year the cane produces fruit and then dies soon afterwards.  However, once planted, new canes continually arise from  buds at the base of old canes and from buds on the roots for sustained fruiting.%0A%0A	The varieties of blackberries that do best here in Tucson are cultivars that have their origin in Texas.  Research done by Dr. Glenn Wright at the University of Arizona's Yuma Agricultural Center indicated that the blackberries ‘Rosborough' and ‘Womack' performed best in the low desert, followed by ‘Brison' and ‘Brazos'.  These varieties are cold hardy down to 5 F, and can be grown even in higher elevations surrounding Tucson.  All have large fruit produced on erect canes that do not require trellising for support, as do trailing types.%0A%0A	 Blackberries can be purchased as potted plants at some area garden centers or as bare-root plants through the mail.  The largest supplier of Texas blackberry cultivars is Womack's Nursery in De Leon, Texas (817) 893-6497.%0A%0A	Blackberries prefer to grow in soils amended with organic matter.  Yard compost, composted manure, and peat are all good forms of organic matter to mix into the soil.  Because row plantings are recommended it's best to prepare the soil in a 3 to 4 foot wide swath, digging organic matter into the top 12 inches of soil.  Remove rocks, stones and any lumps of caliche.  At the same time, till in a general-purpose fertilizer such as 10-10-10 at the rate of one-half pound per 10 feet of row.  Plants should be spaced and planted every 3 feet down the center of the swath of prepared soil.   If multiple rows are desired, spacing between rows should be 10 to 12 feet.%0A%0A	The second year, and thereafter, apply 1pound of 10-10-10 or similar fertilizer alongside the rows in February. After harvesting the berries in May apply an additional one-half pound of fertilizer every 10 feet down the length of the row.%0A%0A	Because blackberries prefer a slightly acid soil ph, it may be necessary to add micro-nutrients if leaves yellow.  Iron, magnesium and zinc can be purchased in ‘chelated' form and applied to the soil in the spring or summer to correct deficiencies.  %0A%0A%0A%0A%0A	Water is critical for newly planted blackberries.  Plants should be watered daily for the first few weeks after planting, then gradually adjusted to provide deep watering two or three times weekly spring through fall.  In the winter, when plants are dormant, water on 14 day intervals.  A 3 inch layer of  organic mulch (compost, straw or shredded wood) should be placed around plants and down the row immediately after planting to conserve moisture and moderate soil temperatures.  This will also help to control weeds.%0A%0A	During the first year of growth, new vegetative canes will grow.   During the summer prune these canes back to a height of 36 inches.  This limits cane height and forces small lateral side-shoots to grow.  It's the side-shoots which bear the fruiting clusters the following year.  Also during the summer remove any shoots that may have grown up outside the parameters of the three foot wide row. If desired, these shoots can be dug out and replanted to lengthen or add more rows of berries.%0A%0A	In the second year, after canes have produced fruit they will die and should then be removed.  This will provide the needed space for continued development of the following year's fruiting canes.%0A%0A	Blackberries are highly perishable. They should be harvested as soon as ripe, usually in May, handled very carefully and either eaten fresh or placed in the refrigerator.   It may be necessary to harvest daily to prevent loss of fruit.  Blackberries will store well in the refrigerator for up to seven days.  Covering blackberries prior to fruit ripening is also recommended to keep the birds for harvesting your fruit before you get a chance! %0A%0A	"Organic Gardening" will be the topic for this week's garden demonstrations. They will be presented on Wednesday at 9 a.m. at the Pima County Extension Center, 4210 N. Campbell Ave (central); and at 1 p.m. at the Wilmot Library (east), and on Friday at 1 p.m. at the Oro Valley Public Library (northwest).  %0A	 %0APlace plants 2 to 3 feet apart in the row at the same depth they grew in the nursery or container. The objective is to produce a continuous hedgerow for the full row length desired. Do not let the cuttings dry out. If the plants or cuttings are slightly dry when received, soak the roots in water for several hours before planting them or heel them in. If plants or roots are extremely dry, reject the shipment.%0A%0AApply fertilizer following recommendations based on soil tests. If soil tests are not available, a general recommendation for the first year is to apply 5 pounds of a complete fertilizer, such as 10-20-10, per 100 feet of row after the newly set plants have started growing or after root cuttings begin to emerge.%0A%0ABrazos has two major advantages over many other blackberry cultivars. It is a semi-erect type that does not require trellising and pruning is also simpler than with other cultivars. The tops of Brazos can be cut low or even mowed down as soon as the harvest season has passed. If cut back at the right time, plants regenerate enough to bear the following spring. With most other cultivars, pruning is somewhat tedious in that two year old canes must be removed each year, leaving only one year old canes.%0A%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161|February 29, 2004|
21|25|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,%0A520-626-5161. |August 15, 2004|
22|26|New Years Resolution for Gardeners -  Grow Tropical Fruit|Why not start the new year off with warm thoughts of Summer and the opportunities that lay ahead in the coming year.  Speaking of opportunities, I have a suggestion for all those gardeners looking for something adventurous to do in the new year.  Why not grow tropical fruits!%0A%0A	Sounds absurd; exotic fruits in Tucson (Chinese Jujube excluded), but you can grow many successfully as long as their grown in containers!  When frosty weather arrives you simply roll or dolly them to a protected location- outdoors or bring them into Arizona Room till warmer weather returns.  Actually any roomy spot indoors will do.%0A%0A	Of course, the best tropical fruits for containers are the ones which are naturally smaller growing.  Many of these fruits grow in shrub or small tree size, and lend themselves to confined container culture.  Here are a list of some interesting ones to try:%0A%0ABarbados Cherry - A large, densely branched shrub or small tree which can be pruned to a central trunk.  Native to the West Indies, Barbados Cherry produces shiny light to deep green ovate leaves and soft, juicy ,thin-skinned, three-lobed fruit that are light to deep crimson when mature.  The fruit has a sweet-tart taste and just one is high enough in vitamin C to meet the daily adult requirements.%0A%0ACarambola - Star fruits, named because of their star-shape when sliced, are widely sold in grocery stores and have a distinctive citrus flavor.  Grown commercially in Hawaii and South Florida, Carambola is a native to Southeast Asia.  Fruit are 2 to 6 inches in length, are light to dark yellow when ripe, and are a good source of potassium.  The varieties ‘Golden Star’ and ‘Arkin’ are self-pollinating.%0A%0ACherry of the Rio Grande - The fruit of this plant, as the name implies, tastes somewhat like cherries and can be eaten fresh or used for making jams and jellies. Fruit are oblong, about an inch in length, and orange ripening to dark red or purple.  Like other Eugenia species it is an attractive plant with dark green, evergreen leaves.%0A%0AJaboticaba - This small bushy tree or small shrub has evergreen foliage and multicolored bark. It’s slow growth makes it ideal for containers.  A native of Brazil, Jaboticaba produces grape-like fruit, with a thick, tough dark-maroon color.  Unlike most other fruit, these grow directly out of the trunk and larger branches, singly or in clusters from the ground up.  Under the skin is a whitish, gelatinous pulp with a pleasant grape-like flavor.  The skin is usually discarded, and only the pulp is eaten.%0A%0AMiracle Fruit - This evergreen shrub grows to a height of 5 feet, under cultivation, and produces small bright red berries.  Although not sweet itself, when the fleshy pulp is savored and allowed to coat the taste buds, everything eaten after that, even lemons, will taste sweet!  The effects last some 30 minutes or more.  You can really surprise your friends with this one.%0A%0AMonstera - This plant is very similar to spreading philodendron in size and appearance.  However the leaves are more rounded in form.  The plant produces a flower cone that develops seeds and a sweet pulp that tastes like a cross between banana and pineapple.  You won’t get much to eat from the fruit of Monstera deliciosa, but what you do get is truly delicious.   %0A%0ASurinam Cherry - This evergreen shrub has ovate leaves which are wine colored when young, turning to a dark glossy-green at maturity.  The fruits are attractive light red to nearly black, They have an unusual ribbed shape, about the size of a bing cherry.  The flesh is orangish and has an aromatic, sweet and somewhat cherry-like, good for jams and jellies.  The plant can be kept cut back on a regular basis and still produce fruit.%0A%0A	Other exotic fruits recommended for pot culture include; Banana, Carissa, Guava, Passion Fruit and Pineapple.  In next weeks column I will discuss the growing of tropical fruits in containers and provide some additional references and resources on the subject.  %0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. %0A%0A%0A|January 4, 2004|
23|27|Growing Tropical Fruit in Containers|%0A	You may have thought it was too cold to grow tropical fruits in Tucson, a point driven home by our recent freezing temperatures.  But many tropical fruits can be grown in containers, and if the containers are on casters, they can easily be moved to warmer locations, even indoors during our periodic cold snaps.%0A%0A	Some of the tropical fruit that grow best in containers are the ones that are typically small, either a shrub or small tree form.  These include; Banana, Guava, Passion Fruit, Pineapple, Barbados Cherry, Surinam Cherry, Monstera, Jaboticaba, Miracle Fruit, Star Fruit, and Cherry of the Rio Grande.%0A%0A	Although you won’t find these plants being sold at local Garden Centers, for obvious reasons, they should be able to order them for you.  Or you can go on-line.  There are several nurseries in California that grow these exotic or tropical fruiting plants.  In addition, you can contact the Southern Arizona Chapter of the California Rare Fruit Growers Association.  Their e mail address is: south_arizona@crfg.org.  They can inform you about membership and plant sales conducted by the Association.%0A%0A	An adequate size container is necessary to grow most of the exotic fruits.  Because they range from medium-sized shrubs, like Surinam Cherry , to small trees like Carambola, a roomy pot is necessary.  Half whiskey or wine barrels work well, as do large plastic pots.  The new feather-lite foam pots are also a good choice.  Because they’re light, even the largest ones can easily be moved about when set on a small platform with rollers. %0A%0A	A 24 inch diameter pot is probably the smallest size I would recommend for growing these plants.  As with any potted plant, the container should have adequate drainage holes. Feather-lite pots usually don’t come with pre-drilled holes.  You can drill your own using a three-quarters or one inch drill bit.  This will be large enough to allow drainage water to escape unimpeded. %0A%0A	As for a soil mix, I recommend using any common bagged potting soil with the liberal addition of perlite.  Mix 4 parts potting soil with one part perlite.  An alterative recommendation is a mixture of 1 part sand, 1 part peat and 1 part small bark chips or perlite.  Do not use straight potting soil as most are too heavy and do not allow for good drainage.%0A%0A	Although most fruiting plants grow best in full sun, here in Arizona, where the sunlight is so intense, mid-day and afternoon shade must be provided from May through September.  It does not have to be a heavy shade, filtered light provided by a mesquite or palo verde tree will be adequate.  If plants have been kept indoors during the winter months, bring them out into direct sunlight, even morning sun, gradually to acclimate them to the increased light level%0A%0A%0A%0A%0A	Tropical and subtropical fruit trees and shrubs cannot tolerate freezing temperatures for very long.  Depending on the variety, the damage might be as light as frozen outer stems or as heavy as freezing back to the soil line.  Root damage can also occur because the root system is not as well insulated from cold in a container as it would be in the ground.    %0A%0A	If you choose to keep your plants outside during cold weather and cover them, be sure to put a heat source under the cover.  Blankets, burlap, frost covers or other protective measures will be insufficient without additional heat.  Cover the plant, pot and all.  Then place a utility lamp with 60 watt bulb under the cover.  This will help keep the soil and plant warmer and will work well for temperatures down to the lower 20° F. range.  Temperatures in the teens will require moving the plant indoors.  Plants moved indoors during these cold spells should be placed away from drafts caused by doors and heating ducts.  %0A%0A	Fruiting plants in containers need adequate nutrients.  I recommend using a timed-release fertilizer from Spring through Fall.  The fertilizer should contain roughly even amounts of nitrogen, phosphorous, and potassium.  Other nutrients in the mix should include: magnesium, iron, manganese, zinc and copper.%0A%0A	Finally, do not expect container grown plants to produce as much fruit as those grown in the ground.  Under the best of conditions many of these plants will produce some fruit, but even if they don’t, you’ll have an interesting plant and a fun experience!%0A%0A	“Pruning Trees & Shrubs” will be the topic for this week’s garden demonstrations. They will be presented on Wednesday at 9 a.m. at the Pima County Extension Center, 4210 N. Campbell Ave (central); and at 1 p.m. at the Wilmot Library (east), and on Friday at 1 p.m. at the Oro Valley Public Library (northwest).  %0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |March 15, 2005|
24|28|Citrus Tree Die-back |The recent cold has frozen the outer growth of many citrus trees here in Tucson.  In most cases only the leaves were killed, but some stems might also have frozen.  But this damage is temporary and will not effect the overall health of the trees.  However, a general die-back of citrus stems and branches is a serious problem and indicates a problem with either the trunk of the tree or the root system.%0A%0A	Damage to the trunk of a citrus tree can occur when soil comes in contact with the base of the trunk.  This can happen if the tree was planted too deep, or settled in the planting hole.  Citrus are very sensitive to having any soil against their trunks.  Even an inch of soil covering the trunk is enough to damage the sapwood and result in a stunting and eventual die-back of the branches.  If this soil is not removed, over time, the tree will likely die.  %0A%0A	Citrus that are watered by basin irrigation are also likely to have soil that has accumulated around the trunk.  It’s a good idea to check the trunk two or three times during the year and to pull back any build-up of soil.  You should be able to see where the first set of roots come out from the base of the trunk.%0A%0A	Both over-watering and under-watering are also causes of die-back in citrus.  Over-watering keeps the soil too wet, blocking soil pores and preventing oxygen from passing into the soil and down to the roots.  Without adequate oxygen, and in the presence of water, fungus present in the soil can attack and kill roots.  This condition is known as root rot.  As the roots die, a corresponding death of the branches occurs, starting with the outermost stems and moving inward.%0A%0A	Under-watering can also cause die-back.  When the tree is not getting enough water, those stems and branches farthest from the roots are the first to die.  A rolling of the leaves, similar to the rolling of a cigar, is the first sign of inadequate watering.%0A%0A	To avoid problems of over or under-watering follow proper citrus watering practices.  Established trees, those planted longer than one year, should be watered once a week during the warm months (April - October) and once every two weeks during the cool months (November- March).  But critical to this schedule is deep watering.  The tree should be watered long enough or with enough water to soak the soil to a depth of 3 feet.  To do this, use a metal rod, such as a five foot long piece of re-bar which can be purchased at hardware or building supply stores.  The rod can be pushed down into moist soil, but will stop when dry soil is hit.  Because of the likelihood of hitting buried rocks, push the probe down in several locations to get an accurate reading.%0A%0A	Over time salts building up in the soil can also cause citrus stems and branches to die.  Salts naturally occur in desert soils, but salts are also added by fertilizing and through irrigation.  The amount of salt in irrigation water is small, but without an occasional flushing, these salts can accumulate to harmful levels.  %0A%0A	To prevent or to correct a salt buildup, citrus trees should be watered heavily at least twice yearly.  A heavier watering than normal will help dissolve excess salts and flush them down below the roots.  The best way to accomplish this is to coil a soaker hose under the tree and let the water slowly seep out for 10 to 12 hours.  The best times of year to do this heavy watering is during a rainy period in the Winter and again during the Summer Monsoon season.%0A%0A	Finally, citrus trees do have a normal life expectancy.  Under good conditions and in milder climates, citrus trees may live to 50 years or more.  But here in the desert that life expectancy is considerably shorter.  A 30 year old citrus tree is considered old and at about that age, it will begin to gradually decline with a dying back of stems and branches.  At that point, it’s best to plant a new, vigorous citrus tree to replace it.  %0A%0A	“Buying the Best Garden & Landscape Plants” will be the topic for this week’s garden demonstrations. They will be presented on Wednesday at 9 a.m. at the Pima County Extension Center, 4210 N. Campbell Ave (central); and at 1 p.m. at the Wilmot Library (east), and on Friday at 1 p.m. at the Oro Valley Public Library (northwest).  %0A	%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |February 1, 2004|
25|29|Blackberries Provide Abundant Crop for Tucson Gardeners|It’s a shame that we can’t grow raspberries here in Tucson, however we can grow the next best bramble, blackberries!  Texas A&M has developed several varieties that grow well in our desert environment, producing an abundance of large, sweet berries. %0A%0A	Blackberries are perennial plants, but each shoot is biennial.  Each shoot only survives for 2 years.  During the first year a shoot, referred to as a cane, produces leaves only.  During the second year the cane produces fruit and then dies soon afterwards.  However, once planted, new canes continually arise from  buds at the base of old canes and from buds on the roots for sustained fruiting.%0A%0A	The varieties of blackberries that do best here in Tucson are cultivars that have their origin in Texas.  Research done by Dr. Glenn Wright at the University of Arizona’s Yuma Agricultural Center indicated that the blackberries ‘Rosborough’ and ‘Womack’ performed best in the low desert, followed by ‘Brison’ and ‘Brazos’.  These varieties are cold hardy down to 5°F, and can be grown even in higher elevations surrounding Tucson.  All have large fruit produced on erect canes that do not require trellising for support, as do trailing types.%0A%0A	 Blackberries can be purchased as potted plants at some area garden centers or as bare-root plants through the mail.  The largest supplier of Texas blackberry cultivars is Womack’s Nursery in De Leon, Texas (817) 893-6497.%0A%0A	Blackberries prefer to grow in soils amended with organic matter.  Yard compost, composted manure, and peat are all good forms of organic matter to mix into the soil.  Because row plantings are recommended it’s best to prepare the soil in a 3 to 4 foot wide swath, digging organic matter into the top 12 inches of soil.  Remove rocks, stones and any lumps of caliche.  At the same time, till in a general-purpose fertilizer such as 10-10-10 at the rate of one-half pound per 10 feet of row.  Plants should be spaced and planted every 3 feet down the center of the swath of prepared soil.   If multiple rows are desired, spacing between rows should be 10 to 12 feet.%0A%0A	The second year, and thereafter, apply 1pound of 10-10-10 or similar fertilizer alongside the rows in February. After harvesting the berries in May apply an additional one-half pound of fertilizer every 10 feet down the length of the row.%0A%0A	Because blackberries prefer a slightly acid soil ph, it may be necessary to add micro-nutrients if leaves yellow.  Iron, magnesium and zinc can be purchased in ‘chelated’ form and applied to the soil in the spring or summer to correct deficiencies.  %0A%0A	Water is critical for newly planted blackberries.  Plants should be watered daily for the first few weeks after planting, then gradually adjusted to provide deep watering two or three times weekly spring through fall.  In the winter, when plants are dormant, water on 14 day intervals.  A 3 inch layer of  organic mulch (compost, straw or shredded wood) should be placed around plants and down the row immediately after planting to conserve moisture and moderate soil temperatures.  This will also help to control weeds.%0A%0A	During the first year of growth, new vegetative canes will grow.   During the summer prune these canes back to a height of 36 inches.  This limits cane height and forces small lateral side-shoots to grow.  It’s the side-shoots which bear the fruiting clusters the following year.  Also during the summer remove any shoots that may have grown up outside the parameters of the three foot wide row. If desired, these shoots can be dug out and replanted to lengthen or add more rows of berries.%0A%0A	In the second year, after canes have produced fruit they will die and should then be removed.  This will provide the needed space for continued development of the following year’s fruiting canes.%0A%0A	Blackberries are highly perishable. They should be harvested as soon as ripe, usually in May, handled very carefully and either eaten fresh or placed in the refrigerator.   It may be necessary to harvest daily to prevent loss of fruit.  Blackberries will store well in the refrigerator for up to seven days.  Covering blackberries prior to fruit ripening is also recommended to keep the birds for harvesting your fruit before you get a chance! %0A%0A	“Organic Gardening” will be the topic for this week’s garden demonstrations. They will be presented on Wednesday at 9 a.m. at the Pima County Extension Center, 4210 N. Campbell Ave (central); and at 1 p.m. at the Wilmot Library (east), and on Friday at 1 p.m. at the Oro Valley Public Library (northwest).  %0A	 %0APlace plants 2 to 3 feet apart in the row at the same depth they grew in the nursery or container. The objective is to produce a continuous hedgerow for the full row length desired. Do not let the cuttings dry out. If the plants or cuttings are slightly dry when received, soak the roots in water for several hours before planting them or heel them in. If plants or roots are extremely dry, reject the shipment.%0A%0AApply fertilizer following recommendations based on soil tests. If soil tests are not available, a general recommendation for the first year is to apply 5 pounds of a complete fertilizer, such as 10-20-10, per 100 feet of row after the newly set plants have started growing or after root cuttings begin to emerge.%0A%0ABrazos has two major advantages over many other blackberry cultivars. It is a semi-erect type that does not require trellising and pruning is also simpler than with other cultivars. The tops of Brazos can be cut low or even mowed down as soon as the harvest season has passed. If cut back at the right time, plants regenerate enough to bear the following spring. With most other cultivars, pruning is somewhat tedious in that two year old canes must be removed each year, leaving only one year old canes.%0A%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161|February 29, 2004|
26|30|Helping Citrus Trees Recover|Our cold winter weather left many citrus looking very scarred and damaged.  Temperatures in the teens caused citrus branches to freeze back.  It also damaged flower buds.  So in addition to brown leaves and frozen stems you may have noticed a lack of flowering. %0A%0A	Citrus flower buds are formed in the Winter, after a certain number of hours below 65 degrees has occurred.  At this stage, the buds are microscopic and it takes warming weather in spring to cause them to grow and eventually bloom.  However, this year, a great number of those microscopic buds froze, thus the lack of flowers now!%0A%0A	There isn’t anything that can be done to replace the frozen buds, however, citrus have been known to put out a second or even third set of flowers in the spring and summer.  So don’t give up hope on getting a crop of fruit.  But there are things that can be done now to help the tree, in general, recover from freeze injury.  %0A%0A	By this time it should be clear what wood has been killed and what wood is still alive.  If new growth has failed to emerge from those brown shoots and stems, it’s time to prune them off.  Cut the wood back to where new growth has emerged.  Use a sharp hand pruners and cut just above the newly emerged shoots.  If stems or branches pencil-sized or larger must be removed, use a long-handled loppers.  %0A%0A	If you’ve not yet applied a spring fertilization to your citrus, go ahead and do it now.  Plant nutrients, particularly nitrogen will help the tree produce new growth to replace that lost in the freeze.  %0A%0A	Contrary to popular belief, fertilizing citrus while they’re in bloom will not damage the flowers or young fruit.  If you’re applying a special citrus food, use it at half the strength recommended.  That’s because most common citrus fertilizers call for the addition of too much nitrogen.  Over-fertilization with nitrogen can adversely effect fruit quality.%0A%0A	When applying fertilizer spread it evenly under the tree and out a few feet beyond the ends of the branches.  Then water the fertilizer into the ground.  If you have a basin for irrigation, just spread the fertilizer in the basin and fill it with water.  If you have drip irrigation, use a soaker hose to slowly water in the fertilizer.   %0A%0A	Sometimes, young leaves will be yellowed. If the yellowing occurs in between the veins, while the veins remain green, it's likely an iron deficiency. This is an excellent time to apply iron to the soil around your citrus trees. With warming temperatures the iron is taken up by the roots and distributed to new growth and deficient leaves. Be sure to buy chelated (water soluble) iron. It's more expensive, but it's the only type that works in our soil.  The most commonly available type of chelated iron, and one that works very well is  Sequestrene 130.  Look for it listed on the label of chelated iron products.  %0A	In the spring, new growth may be attacked by small green, soft-bodied insects called aphids.  Although they don’t do any significant damage, it’s a good idea to get rid of them on recovering citrus trees.  Usually, a strong spray from a garden hose attachment is enough to knock them off the leaves.  Soap sprays, made by mixing one tablespoon of liquid dishwashing detergent in a gallon of water, also work well.%0A%0A	Above all, recovering citrus trees must be kept well-watered!  This means giving the tree more than ‘just enough’ if you want the tree to thrive.  Adequate water is also critical to the development of quality fruit in terms of size and sweetness. %0A%0A	A broad and deep soaking is needed every 5 to 7 days for established trees in hot weather.  At a minimum, water out to the edge of the branches and at 2 feet deep - 3 feet is better.  If your using drip emitters, it may take several hours of running to get the water down that deep.   Deep soil moisture provides a large reservoir for citrus roots to draw water from in hot weather.  %0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona 520-626-5161. |April 11, 2004|
27|31|Many Factors Effect Citrus Fruit Quality|Citrus trees will be blooming shortly, followed closely on by the formation of small pea-size citrus fruits.   As these fruits grow and develop over the spring and summer, certain aspects of care given to the tree can enhance the sweetness, quality and number of fruit.  %0A%0A	At this time of year it’s important to fertilize citrus to supply an adequate level of nutrients for the development of healthy growth and fruit formation.  Nitrogen is the most important nutrient to be supplied.  Ammonium sulfate (21-0-0) has 21%25 nitrogen and is the standard citrus fertilizer used in Arizona.  However, from time to time it’s good to add phosphorous to the mix.  Ammonium phosphate (16-20-0) has both nitrogen and phosphorous and can be used for one or all of the recommended three yearly fertilizations.  Unlike nitrogen, phosphorous must be scratched into the top half-inch or so of soil to be absorbed by the roots.%0A%0A	A word of caution about fertilizing citrus - don’t overdo it!  Too much fertilizer, in particular - nitrogen, can adversely effect the quality of fruit.  In fact, grapefruit should be fertilized with only half the amount recommended for other types of citrus.  Too much nitrogen, and the rind of grapefruit will become excessively thick!%0A%0A	If your citrus tree has dark green leaves and adequate growth, you can lighten up on the amount of fertilizer applied, or skip one of the three (February, May, September) recommended%0Afertilizations all together.  %0A%0A	Because of our prolonged warm winter weather, flowering has already begun on many trees and may coincide with the recommended February fertilization.  Contrary to popular belief, fertilizing citrus trees during flowering or early fruit set does not adversely effect blooming or fruit development. %0A%0A	Adequate watering is probably the most critical aspect in the development of quality fruit.  Fruit that’s dry on the inside with dry pulp is a frequent complaint of backyard citrus growers.  It’s most often caused by lack of sufficient water when the fruit is developing. Fruit cracking is also related to watering problems.  The outer rind can spit open when the tree is lacking water and is then give lots of water, either by irrigation or rainfall.  The sudden swelling of the fruit can split the outer rind.  If watering is consistent, splitting is less likely to occur. %0A%0A	Watering should be increased at the time citrus begin flowering.  In fact, from the onset of blossoming to the time fruit are quarter-size in diameter, extra water should be supplied.  Where as the recommended watering would normally be one time per week, increasing to twice weekly during this period should lessen fruit drop and improve fruit quality.  If you have sandy, well-drained soil it may be necessary to water three times weekly - but with a smaller amount per application.%0A%0A%0A%0A	Deep watering is the key to success.  If you’re irrigating with drip, run the emitters long enough to soak the water down 2 to 3 feet deep.  This may take several hours.  If you only have two or three emitters per tree add more emitters or use a soaker hose to supplement your normal watering.  %0A%0A	If adequate water is applied to the tree(s) during the growing season, then fruit should develop properly.  The sugar content of the fruit will depend on the stage of ripening.  To have an appealing taste, the fruit must have a balance between these sugars and acids.  Too much acid and the fruit is bitter.  Too much sugar and the fruit is bland and tasteless.  Of course, tart lemons and limes will have a much higher acid content than oranges and mandarins. %0A%0A	The variety of citrus will determine it’s ripening range.  For instance, Valencia is a late ripening variety of orange that is at peak quality sometime between mid-January and mid-March.  Most citrus fruit, such as Valencia, should be tested weekly for taste during it’s ripening range.  When the fruit tastes good, it’s ready for picking.  The exception is grapefruit.  Although grapefruit may be picked as early as December, the sweetness and quality will continue to improve into early spring. %0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona, 520-626-5161. |February 20, 2005|
28|32|Oriental Persimmons - Attractive & Delicious!|Oriental also called Japanese persimmons are great fruit trees for most of Southern Arizona from Tucson to Sierra Vista and points between.  Although considered a sub-tropical fruit, Oriental persimmon can tolerate temperatures as low as 10° F and as high as + 100° F.  Their fruits are a beautiful orange red, peach-sized, sweet and distinctive. %0A%0A	Oriental persimmons (Diospyros khaki L.) are divided into two major categories: astringent (puckery) and non-astringent.  Popular astringent types such as: Hachiya, Tanenashi, Eureka, Saijo and Yokono must ripen to become soft, somewhat mushy, before losing their pucker power.  Popular non-astringent types including; Fuyu, Matsumoto Wase Fuyu, Jiro, Izu, Hanagosho, and Suruga are not astringent even when unripe.  The most popular Fuyu is firm when ripe having the consistency of an apple and is eaten in the same manner.  %0A%0A	Astringent persimmons are eaten soft, usually eaten in hand or cut in half and served with a spoon.  They’re also great for flavoring ice cream and yogart, and baking in cakes, cookies and puddings.  Astringents such as Hachiya are extremely sweet when ripe, a real treat picked soft off the tree or after they’ve fallen to the ground.  Ripe fruits can be frozen whole or pulped and frozen to store.  Fruit pulp can also be dried.%0A%0A	Trees range in size from 15 to 25 feet at maturity, with a somewhat smaller spread.  The semi-dwarf cultivar ‘Ichikikei-Jiro’ grows only 6 to 8 feet tall.   In general, Oriental persimmons trees have a relatively open, sometimes willowy canopy of attractive blue green oblong shaped leaves great for providing shade.  Orange-yellow fall leaf color is also nice.  But the showiest aspect of the tree are the large orange to red-orange persimmons.  About the size of tennis balls, the persimmons are capped by a distinctive green caylx somewhat like a tomato only larger and more pronounced.  Fruit ripen, depending on the variety from September through December.  As the leaves are shed in the fall, the orange fruit hangs on the branches like large tree ornaments.  %0A%0A	The trees will grow in many different types of soils but should be planted on moderate to well drained soils away from caliche layers.  Select a site in full sun.  Container grown trees can be purchased and planted anytime.  Bare-root trees, available from mail order sources, should be planted December through February. %0A%0A	Oriental persimmons are self-fruitful, so only one tree is needed to produce fruit.  Trees are 5 years old when they begin bearing fruit.   As most plants purchased from local or mail order sources will be at least 2 years old, you’ll have 3 years or less after planting before trees begin bearing fruit.%0A%0A	The best time to plant persimmon trees are in October or February.  If you purchase a bare-root tree it should be planted in February.  Container grown trees can be planted anytime, although the best time to plant these would be in October or March.  Trees should be planted directly in existing yard soil.  Test drainage prior to planting.  Dig a hole 12 inches wide and 18 inches deep.  Fill with water and let drain.  Fill it a second time and time how long it takes for the hole to drain.  If it drains in 48 hours or less, it’s a suitable location for planting your persimmon.  If it doesn’t, look for another spot.  %0A%0A	A newly planted tree should be watered daily for the first three or four weeks, then gradually increase the days between watering.  After the first year, the tree is considered established and can be placed on a permanent watering schedule - once or twice weekly spring through fall and once every two weeks during the winter.%0A%0A	Persimmon trees need periodic applications of nitrogen and phosphorous.  Start fertilization beginning the season after planting.  I recommend using ammonium phosphate (16-20-0) at the rate of one-half pound (approximately one cup) per application in early March, late June and in late September for young trees.  After three or four years of growth, increase the amount of fertilizer applied to one pound (two cups) per tree, per application.   %0A%0A	Unlike other deciduous fruit trees like peach and plum, persimmons do not need annual pruning.  Just keep the any dead wood cut out and prune for size control if necessary.  Any pruning should be done during the dormant season.%0A%0A	Check with your local garden center for availability of trees.  Several on-line nurseries specialize in Oriental persimmons.  They include; TyTy Nursery at: www.tytyga.com,  Trees of Antiquity at: www.treesofantiquity.com and Raintree Nursery at: www.raintreenursery.com %0A%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161. |May 8, 2005|
30|34|Grapes Produce Abundant Crop|Grapes are abundant producers here in Southern Arizona.  In fact, not that many years ago, Pinal County to our North was a major producer of table grapes with some 1500 acres of vineyards.  Arizona’s wine grape production is centered not far from Tucson in Santa Cruz and Cochise County with commercial vineyards as close as Veil.  So, it’s possible to grow a variety of European table and wine grapes in home gardens in and around Tucson.  %0A%0A	Probably the most abundant grape variety for Southern Arizona is Thompson Seedless.  It’s one of the most popular grapes for eating fresh with a sweet but mild flavor.  The berries are medium-sized and the clusters large with greenish white to golden berries.  Thompson Seedless is the variety most often used for making raisins.  Other recommended table grape varieties include; Cardinal(dark red berries), Perlette (pale green berries), and Flame Seedless (red berries).%0A%0A	If your interested in making wine, several European wine grapes also grow and produce well in our area.  Some of the best reds for our hot climate include; Shiraz, Petite Sirah, Barbera, Tempranillo and Cabernet Sauvignon.  Recommended white wine grapes include; Sauvignon Blanc, Viognier, and Pinot Grigio.%0A%0A	Grapes should be planted in a full sun locations and well-drained soils.  Test the drainage by digging a hole 12 inches wide and 18 inches deep.  Fill the hole with water and let it drain.  Fill it a second time and observe how long it takes for the water to drain from the hole.  If the water drains out in 48 hours or less, the soil has adequate drainage for growing grapes.  %0A%0A	Grapes can be purchased from local garden centers in containers or bare-root from mail-order nurseries.  Container grown grapes can be planted Spring through Fall.  Bare-root grapes are ordered and planted during the Winter months.  Regardless of the type, grapes should be planted directly in unamended soil.  No organic amendments should be added at the time of planting.  Just dig a hole large enough to accommodate the roots, removing any stones or caliche from the hole.  Loosen the soil and fill in around the roots.%0A%0A	Grapes can be trained to grow on trellises, arbors or single posts.  If your planting several grape vines it’s best to build a trellis using 4 by 4 inch wood posts or heavy metal T posts spaced 15 to 18 feet apart.  Two heavy gauge wires are attached to the posts, the first at 36 inches above the ground and the second at 60 inches above the ground.  The first wire is used to train the fruiting cane, called the cordon.  The second, or upper wire is there to support the fruit-producing shoots.  %0A%0A	The most effective method for training and grape production is the unilateral cordon system where grapes are planted 6 feet apart and trained to grow in one direction down the trellising wire.  The first growing season, a single shoot is selected to grow up a small supporting stake to the trellising wire and then down the wire in one direction.  The grape vine is attached to the support stake and wire with Velcro plant ties or plant tape.  In the second season fruiting spurs are developed every 4 to 6 inches along the vine, referred to as a cordon.%0A%0A	Irrigation of the grapes is best accomplished using drip irrigation, with two one-gallon drip emitters placed on either side of each grape plant.  Grapes need ample water, especially during the first two or three seasons as they are becoming established.  After establishment, grapes will need regular watering from 2 to 4 times weekly during the growing season and fertilization with a high nitrogen fertilizer in early spring and in the fall.%0A%0A	For more information on growing grapes, send a self-addressed, stamped envelope to: ‘Growing Grapes at Home’, University of Arizona / Pima County Extension, 4210 N. Campbell Avenue, Tucson  85719-1109.%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161. 	%0A%0A%0A%0A%0A %0A%0A%0A%0A%0A|July 16, 2006|
29|36|Fall is Citrus Planting Time|Fall is the ideal time to plant citrus trees.  With cooler air temperatures, newly planted trees are less prone to stress.  In addition still warm soil temperatures are conducive to new root growth and tree establishment before the onset of colder winter weather.%0A%0A	There are many types of citrus to choose from and a good selection is now available at area garden centers.  Oranges are the most popular among home gardeners.  If you want an orange for eating, Arizona Sweets are hard to beat!  They ripen December through February and can be used to make fresh-squeezed juice as well.  But if you’re mainly interested in juicing your oranges, far and away the best is the Valencia orange.  It’s a late season variety that ripens February through May.  %0A%0A	Grapefruit are also popular and a good choice for colder spots around Tucson.  But you might want to try an alternative to grapefruit called Oroblanco.  It’s a grapefruit crossed with a pummelo that creates a juicy sweet grapefruit-sized fruit, but without the bitterness of grapefruit! %0A%0A	This year, for the first time in a long time, it’s once again legal for garden centers in Arizona to sell Myer and Improved Myer lemons in Arizona.  Thought to be the best of all lemons by most home gardeners, Myer is actually a cross between a true lemon and an orange.  The rind of Myer lemons is orange-yellow and it’s deep yellow flesh is decidedly sweeter than a lemon but still has plenty of tang!%0A%0A	Still, if you have only enough for one citrus tree in your yard, that citrus should be a Mineolla tangelo.  A cross between a Dancy mandarin and a Duncan grapefruit, Mineolla is arguably the sweetest and juiciest of all the citrus fruits with a unique mandarin-orange flavor.  Its  deep orange-red fruits are easy to peel and are great for eating fresh or juicing.%0A%0A	When purchasing a citrus tree, choose one that has lots of dark green leaves and a sturdy trunk.  The best size citrus trees to buy are ones in 5, 7 or 15 gallon containers.  They’re easier to handle and establish faster after planting than do larger boxed citrus trees%0A%0A	Most citrus require a space of 10 feet by 10 feet to grow and should be planted a minimum of 6 feet from house or property walls or fences.  The hole dug to plant your tree should be shallow and wide, no deeper than the depth of the root ball and about two to three times wider.  When set in the planting hole, the top of the root ball should be flush with the surrounding soil.  Citrus planted too deep will struggle and likely die!  %0A%0A	Fill in around the root ball with the soil dug from the hole.  Do not mix compost, manure or other organic amendments into the backfill soil!  This creates a pot-in-the-ground effect that %0Awill prevent the roots from growing out in the surrounding soil.  Contrary to popular belief, citrus trees will grow just fine in our desert soils as long as there is adequate drainage.  %0A%0A	After filling the planting hole with soil, minus any large rocks, thoroughly water to settle the soil and moisten the root ball.  Water two or three times weekly through the end of November.  Then reduce watering to once weekly through the winter months.  %0A%0A	If you would like our free University of Arizona “Citrus Varieties” publication covering all the types of citrus that can be grown in the southern Arizona, send a self-addressed envelope to: Citrus, 4210 N. Campbell Ave, Tucson Az.  85719%0A%0AWritten by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161. |October 16, 2005|
31|37|Edible Ornamentals|Any plant that provides edible seeds, fruits, flowers, leaves or other plant parts would be considered an edible plant.  As for it’s ornamental properties, all plants have an aesthetic appeal to one degree or another. But some plants are both highly ornamental and very good to eat!   Some of these edible ornamentals great for Tucson gardens include:%0A%0A	Globe Artichoke are grown for their delectable immature flower buds.  Here in Tucson fall planting is a must so that flower buds can be harvested before hot spring temperatures turn the tender buds tough and inedible.  Some of the buds should be left to come into their  spectacular bloom of cushiony globed purplish-blue, nearly florescent flowers .  %0A%0A	Sunflower seeds are great for snacking, grow fast and come in every size and flower color imaginable.  Not only do they grow fast, but their extremely easy to grow from seeds making them a kids gardening favorite.  Some of the best full-sized Sunflower Sunflower varieties are ‘Mammoth Russian, ‘Cyclops’and ‘Paul Bunyan’.   All grow 10 to 12 feet tall.  But there are also Sunflower Sunflower varieties like ‘Sunflower Elf’ ‘Sunflower Elf’ that grow less than 2 feet tall.  Color selections include the traditional yellow ray brown disk flowers, red, crimson, bronze, orange and white.%0A%0A	Great selections of Sunflower variety seeds are available from the Burpee Seed Company at www.burpee.com and Seedman at www.seedman.com %0A%0A	Pomegranate is a beautiful large shrub to small tree that thrives in desert heat.  The fruits are red to red-orange, large and highly decorative.  Fruits ripen 6 to 7 months after flowering.  Pomegranate Pomegranate fruit should be cut off using a sharp hand pruners at maturity.  Fruit will not ripen off the tree.  Under the hard outer shell is a seedy pulp that’s tart and sweet.  The pulp can be eaten fresh or juiced.  Flowers are also an orangy-red and showy.   The cultivar ‘Wonderful’ produces the best quality fruits.%0A%0A	Grapes are gaining increased popularity as the vine of choice for many home gardeners.  Lush edible leaves and the fruit clusters are as beautiful as they are juicy sweet.  Grape vines blend beautifully with Mediterranean-style gardens.  The most vigorous grape variety for our desert environment is the Thompson’s Seedless table grape.  But many wine grapes also preform well in the heat including;  Syrah (a.k.a. Shiraz) Syrah (a.k.a. Shiraz), Tempranillo, Barbera and Petite Sirah.  Grapes grow well on arbors and trellises or can be trained to grow free-standing much like a small tree.%0A%0A	Peppers can be sweet, spicy or hot but all have attractive fruits in a range of colors including; near black, purple, red, orange, gold and green.  New pepper varieties are always being introduced into the market.  Some of the best are the All American Selections, like the 2006 award winner ‘Carmen', an improved sweet pepper with an unusual shape.  Rather than the typical bell, Carmen has an elongated chili pepper form.  Fruits are quick to mature to a bright red, but are sweet and edible while still green.  %0A%0A	Edible Flower Petals are gaining popularity for using as garnishes, additions to salads and for flavorings in beverages, jams and jellies, cheese spreads, and herbal butters.  Some like squash flowers and dandelion blooms can be fried in a light batter or cornmeal.  Others can be stuffed or used in stir-fry dishes. Some popular flowers with desirable flavors include; Nasturtium (peppery flavor), Viola(sweet), Hibiscus(citrus to cranberry), Rose(perfumed, sweet to bitter), and Dianthus(spicy, clove).  %0AA word of caution.  Even edible flowers may not agree with some people.  Have a small taste just to see if you suffer any ill effects before consuming more.%0A%0A%0A Written by John Begeman, College of Agriculture and Life Sciences, the University of Arizona,%0A520-626-5161. %0A%0A%0A%0A|July 2, 2006|