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Backyard
Fruit Production at Elevations 3500 to 6000 Feet Written by
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CHERRY
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Vital Statistics
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Crop
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Years to Bearing Age
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Height at Maturity (ft.)
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Spread at Maturity (ft.)
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Life Expectancy (yrs.)
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Unpruned
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Pruned
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Apple
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4-8
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40
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20*
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30-40*
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20-30
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Apricot
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3-4
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30
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15
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30
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30
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Cherry
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4-6
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40
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25*
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30*
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20-30
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Fig
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2-3
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40
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6-25
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25-60
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30-40
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Peach/Nectarine
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3
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25
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15
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25
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15-20
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Pear
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4-8
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40
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15
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25
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25-45
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European Plum
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4-5
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30
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15
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25
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20
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Japanese Plum
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3
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30
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15
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25
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20
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* Can be reduced with dwarf or semi-dwarf rootstocks.
- Improper irrigation: Water often (every 2-3 days) but lightly.
- Lack of weed control: Weeds rob a young tree of moisture,
nutrients and sunlight. Keep out weeds by using surface mulches such
as bark chips.
- Poor quality trees.
- Improper handling.
Trees should be pruned immediately after planting. Cut back top 1/3 or more. Remove all shoots from poorly branched tree. Some lower shoots can be left on well-branched tree. After tree is trained to desired shape and conformation (after two growing seasons), only minimal corrective pruning is needed. Excessive pruning can delay time of first flowering. Fruit trees are pruned during the winter dormant season every year. For further information, see Pruning Fruit Trees, Publication Number 110377.
Train apple trees to a central leader. All side limbs are developed from a central axis like a Christmas tree. Fruiting spurs, which are the short shoots that bear flower buds, occur on wood two years and older and are productive for 5-8 years. Fruit is produced terminally (on the ends) on spurs. Prune trees with thinning cuts, i.e., remove the entire shoot where it originates. Heading means cutting off part of a shoot or limb rather than removing the entire shoot or limb at a branch point. Head the leaders (but not the secondaries) annually to stiffen them. Spread limbs using weights, wooden spreaders, etc. to form crotch angles of at least 50 degrees.
Train apricot trees to a vase shape. Fruit is produced laterally on short-lived spurs. Because the fruit-producing spurs are short-lived, remove side branches throughout the tree to cause new spurs to be formed. Thin out limbs growing into the center of the tree, allowing more light penetration.
Sweet cherries produce fruit laterally on long-lived spurs that are productive for 10-12 years. They need less renewal wood than nearly any other deciduous fruit tree. Thin out new shoots annually. Tart cherries produce fruit on one year old wood. Thin out limbs growing into the center of the tree, allowing more light penetration.
Pruning should be less severe than for other fruit trees. Prune to form a vase shaped tree. Fruit is borne on shoots of current season’s growth. Thin out wood in center of tree.
Peach and nectarine trees are pruned to an open center shape. Branching is developed toward the outside of the tree, giving it an overall vase shape. They are pruned more heavily than other deciduous fruit trees. Fruit is produced laterally on shoots of the past season’s growth. Prune to thin out one-year old wood and top to maintain tree height.
Pear trees are trained to a central leader or a vase shape. Fruit is produced terminally on long-lived spurs. Use thinning cuts to remove one-year old wood. Follow same guidelines for apples.
Trees bear fruit on current season’s growth. They need little pruning. Thin shoots (length of branch growth in a single season) to promote growth for next season’s crop.
Fruit is produced laterally on long-lived spurs. Prune by moderate thinning of lateral fruiting wood.
These trees bear fruit on long-lived spurs and on one-year old shoots. You can sacrifice this production by removing one-year old shoot growth each year in order to shape the trees. Leave unheaded shoots 12- to 18-inch long to develop spurs in the 2nd and 3rd years.
There are several reasons to thin fruit — to reduce limb breakage, increase fruit size, improve fruit color and quality, and stimulate floral initiation for next year’s crop. Home gardeners thin fruit trees by hand. During May and June, many fruit trees will drop or abort fruit. This is a natural process that allows the tree to mature the crop load.
The best time to thin is within 20 to 40 days of full bloom. Space each apple 6-8 inches apart on the branch. In clusters, leave the king bloom (the center bloom in the cluster of five flowers) as it will develop into the largest fruit.
Thin when fruit is 1-inch in diameter. Because trees are heavy producers, apricots should be severely thinned. Space fruit 6 inches apart after frost hazard has passed.
Thin fruit when 1-1¼ inch in diameter. Space fruit 6-10 inches apart on the branch.
These trees seldom require thinning. Remove small or blemished fruit as soon as they are seen. Leave two fruits per cluster to improve size.
These fruits are not thinned.
Thin when the fruit is large enough to be easily picked. Space plums 4-6 inches apart on the branch and break up clusters.
Fruit trees should be fertilized annually in February or March. Nitrogen
(N) is the most important nutrient to apply. If N is deficient then
older leaves will turn yellow.
Example: An apple tree has a 2-inch trunk diameter, so it needs 0.2 lbs. of actual nitrogen. Ammonium phosphate (16-20-0) contains 16% actual nitrogen; i.e., there are 16 lbs. of actual nitrogen in 100 lbs. of fertilizer. 0.2 lbs.÷16% = 1.25 lbs. You need to apply 1.25 lbs. of ammonium phosphate to supply 0.2 lbs of actual nitrogen to the tree.
Minor elements most often deficient are iron and zinc. Both nutrients,
when applied to deficient soils, are quickly tied up chemically in the
soil so that they are not available to the tree. One way to remedy micronutrient
deficiencies is to apply them to the leaves in chelated form. Foliar
sprays are most readily absorbed by young expanding foliage.
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Crop
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Amount of N per inch of Trunk Diameter
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Apple/Pear
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0.1
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Apricot, Cherry, Peach/Nectarine, Plum
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0.05
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Iron deficiency causes a yellowing of new leaves while the veins remain green. Irrigating too frequently in the spring can induce iron deficiency. Symptoms of zinc deficiency include shortening of the space between leaves or nodes so many leaves are bunched at the twig end (rosetting), small leaves, and in severe cases brown areas on leaves.
For maximum tree and fruit growth, water needs must be satisfied from
bud swelling through harvest. Watering frequency during the growing
season can vary from 7 to 21 days, depending on the age of tree, climate,
and soil type. Young plants have small root systems and require close
attention. Be sure to use a soil probe — a metal rod, or an auger
to determine dryness of soil.
Mature fruit trees respond to deep watering; saturate the soil to a
depth of 2-3 feet. Build basins to extend past the tree’s drip
line (an imaginary line extending to the outer edge of the plant canopy).
Mulches will help conserve moisture. Use an organic mulch, such as straw
or bark chips, 6 inches thick; keep the mulch away from the tree trunk
to lessen crown rot.
Normal fruit development depends on a continuous supply of water. For
example, the red or yellow color of apple fruit will not develop properly
if trees are stressed for water. Other problems aggravated by improper
timing include split pits of peaches and cracks on prunes.
Not only does proper watering allow the fruit to develop normally on
the tree, but summer irrigation helps the crop for the following year.
Flower buds are initiated in the summer and develop in the fall. Dry
soil this summer will cause apple and pear trees to have a heavier bloom
and a reduced fruit set next spring. Peach, plum, and apricot trees
react differently to summer water stress; they will have little or no
bloom the following spring.
Once fruit has been harvested, continue periodic irrigation until leaves
fall and then let the tree harden-off when going into winter. Remember
that as long as the leaves remain green, trees will use water. Irrigation
also may be needed in winter, especially with high temperatures or inadequate
winter rains. Remember dry roots die!
Fruit trees are very sensitive to excess salt - either in the soil or in the irrigation water. Electrical conductivity, (EC) is a measure of salinity; the more salt ions in the water, the better it conducts electricity. If soil EC levels are greater than 2.5, salts may damage the tree. The first symptom of salt burn is brown or yellow margins on leaves. Frequent, shallow irrigations can cause salt to accumulate in the root zone. You can remove much of this salt by leaching the soil. To leach soil, apply four or five times the amount of water for a normal irrigation. Late fall is a good time to do this leaching because trees are dormant and less susceptible to waterlogging.
Fruit trees in Arizona do not suffer from many of the problems experienced in other parts of the country. Many plant problems are caused by people and their actions and not by insects, microorganisms, or nutrient deficiencies. Assistance can be obtained from your local Extension Agent or Master Gardener. The most common insect and disease problems are listed below.
Codling
moth (Cydia pomonella) larvae are found in apple and pear
fruit during the summer. Fully grown larvae are pinkish-white with a
brown head and ½ – 1 inch long. There are usually three
generations of codling moth per year. The first flight of moths occurs
over a 6-week period, depending on spring temperatures, in April and
May. Second and third peaks of moth activity usually occur in mid-July
and mid-August, respectively.
Peach
tree borers (Synanthedon exitiosa) attack apricot, cherry,
nectarine, peach, and plum trees. The peachtree borer is a white worm
about 1 inch long that works underneath the bark near the ground line,
often injuring or killing the tree. The adult emerges in July, August
and September. The female moth is a dark steel blue to shiny black with
orange bands around the abdomen. Egg laying begins shortly after the
moths appear.
Other insect pests include:
Peach twig borer.........................................Anarsia lineatella
Pear blister mite .........................................Phytoptus pyri
Pear slug ...................................................Caliroa cerasi
Plum curculio ............................................Conotrachelus nenuphar
San Jose Scale .........................................Quadraspidiotus periciosus
Two spotted spider mite ...........................Tetranychus urticae
Western flower thrips ...............................Frankliniella occidentalis
Wooly apple aphid ..................................Erisoma lanigerum
Leaf-footed plant bugs ............................Leptoglossus zonatus
Scale insects ..........................................Diaspididae family
Plant
diseases which can be found on fruit trees at these elevations include
fireblight (Erwinia amylovora), a bacterial disease found
on pear and apple trees, and brown rot (Monilinia fructicola),
a fungal disease which attacks the blossoms and fruit of peach and plum
trees. Shot-hole disease (Wilsonomyces carpophilus) occurs
occasionally on peach and cherry trees. Powdery mildew (Podosphaera
sp.) is a fungus disease that may be found on susceptible varieties
of apple. Phytophthora crown rot causes a root and crown
rot of various fruit trees. Texas Root Rot (Phymatotricum omnivorum)
is a fungal disease of the roots, often causing trees to die rapidly
in late summer.
These publications are available at County Extension offices and on-line
at http://ag.arizona.edu/pubs/
Fire Blight, Arizona Cooperative Extension AZ1030, Mary W. Olsen
and Deborah J. Young,
1998
Arizona Master Gardener Manual, Arizona Cooperative Extension,
1999
Guide to Symptoms of Plant Nutrient Deficiencies, Arizona Cooperative
Extension, Shanyn Hosier and Lucy Bradley, 1999
Planting Guidelines: Container Trees and Shrubs, Arizona Cooperative
Extension AZ1022, Jimmy L. Tipton, 1998
Powdery Mildew, Arizona Cooperative Extension AZ 1033, Mary
W. Olsen and Deborah J. Young, 1998
The University of Arizona is an Equal Opportunity/Affirmative
Action Employer. Any products, services, or organizations that are mentioned,
shown, or indirectly implied in this publication do not imply endorsement
by the University of Arizona.
Document located http://cals.arizona.edu/pubs/garden/az1162/
Published February 1999
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