Gardening with Gary

Gardening Advice from an Expert

Fruit Trees

Takpro writes~ I have a weeping cherry tree and a purple leaf plum tree that refuse to produce more than a few blooms each. Both have been in the ground for 3 years and are otherwise healthy and growing. My soil test indicated a good level of phosphorous and because this has been an ongoing problem, I have even supplemented with superphosphate on several occasions. Do you have any suggestions on what might be going on?

You mention testing the soil for Phosphorus, which is good. But, have you measured the pH of the soil? They prefer to grow on the a slightly acidic side, a bit lower than 7.0 neutral. That is why they thrive near azaleas, camellias and rhododendrons. Purchase a test kit at a local nursery or garden center. If your soil is rather basic, then flowering will be sparse.

The age is a determining factor as well. Three years is not a long time for the trees to establish themselves. Be patient and give them a couple more years. My research leads me to believe that 4-6 years is an average time span for full ornamental flowering. You will soon be rewarded.

They prefer moist, fast-draining, well-aerated soil, and require full sun. Keep roots moist; these trees are not tolerant of prolonged drought, but do tolerate heat and high humidity.

Pruning is seldom necessary except to remove dead or diseased wood, or crossing branches that appear awkward or rub against each other. To avoid reducing the following year's flower display, prune crossing or rubbing branches immediately after flowering. Never prune in early spring before flowering. Prune dead or diseased wood any time of year.

It is important to maintain healthy trees free from insects and diseases. Most diseases and insects can be controlled through periodic applications of an "All-purpose Fruit Spray". These sprays are mixtures of fungicides and insecticides, and are effective against most fruit tree pests.

Also, be sure to keep down any weeds around these trees as they cannot only deplete the area of nutrients and water, but harbor insects and diseases.

Assistance from: The Clemson University Cooperative Extension Service and The Michigan State University Extension [my alma mater].

Shellie writes~
I would like to know when and how to take a start from my neighbors black elderberry tree?

A. Here is a general background:

A deciduous shrub from 20" to 20' in height.
Leaves large, opposite, compound with five to nine leaflets.
Stems: Young twigs soft and pithy, but the wood is quite hard. The stems may have a rank odor if bruised.
Flowers creamy white in pyramidal heads.
Fruits round, berry-like drupes with two to four seeds; usually bright red, although that of var. melanocarpa are black.

Across North America from Newfoundland to Alaska. Restricted to moist, cool sites in the South, extending into California in the coastal mountains, Arizona and New Mexico in the Rockies, and Georgia and Tennessee in the Appalachian highlands. Not well adapted to warm climates and in the southern part of its range is found in cooler uplands, swamps, and along cool drainage.

Prefers rich rocky soils with ample moisture; will tolerate saturated soils with a pH of 5.0 to 8.0.

Shade tolerant or partially shade tolerant. Where it grows under a canopy, it develops poorly, is lower height, and fruits sparingly, if at all.

Fire:
Can resprout from rhizomes or root crowns following fire. Fire generally kills above ground parts which resprout. Sprouting can occur from dormant buds on the stems following a very light fire. If stem buds are killed in a higher severity fire, sprouting can occur from rhizome or root crown buds. A very severe fire might expose and kill the rhizome or root crown and thus the plant.

Regenerates vegetatively from sprouts, rhizome suckers, and layering. Living stems growing from the rhizome suppress rhizome bud growth. Seedlings form a thickened crown with buds which can become a rhizome by the third year.

By seed, following cold stratification.
**Can be propagated by cuttings, either using hardwood cuttings started in the winter or softwood cuttings during the spring or summer. Cuttings of rhizomes with stems can also be transplanted. All varieties can survive either by sprouting from root crowns or rhizomes.**

Assistance from: www.rook.org/earl

Q. I am so unhappy watching my fruit flowers start to open and then fall off! What can I do yo stop this?

A. Gardeners in warm, humid climates will soon be fighting bud blast. If the buds on your flowers and fruits dry up and fall off before they bloom, the fungus Botrytis is probably the cause. The disease thrives in warm humid areas where air circulation is poor. Here are some suggestions to help combat bud blast:

Remove all affected parts of the plant and destroy them.

Clean up any debris that may have fallen around the plant.

Remove old mulch.

Space and prune plants so that there is plenty of room for air to circulate.

Spray with a fungicide such as Benomyl. Check at your local nursery and please follow the label directions exactly. Spray in the morning on a still day and repeat as directed to gain full control.

Assistance from: Garden Guides

Lola writes~
I have two apple trees and two peach trees and every year my apples have brown spots on them. I would like to know what causes them and what I can do to stop it. Also when do I spray far insects and what do I spray with. I would appreciate your help. I would like to grow some pretty apples.

A. Apple tree black rot is a plant disease caused by the fungus of the physalospora species. This plant disease attacks pears as well as apples. Fungi of the physalospora overwinter in rotted apples and cankerous lesions on apple trees and emerge at temperatures as low as 55 degrees F to spread again. Black rot is an especially dangerous disease to apple trees and the harvest if left uncontrolled.

Black rot infected regions of the apple tree should be pruned out, being sure to destroy all infected fruit, twigs and branches. Do not just prune the areas and let them drop as that can release more spores to otherwise unaffected regions of your apple tree. Be sure to carefully prune out any cankerous lesions no matter how small they seem and going at least 8" around the visible cankers, because the lesions will grow if left unattended and do extend beyond the visible lesion. Also be sure to clear and destroy all infected plant debris. Unfortunately, once the fruit has begun to rot and die, fungicidal treatments are no longer helpful. However, you can be prepared next year when the spores may reinfect new apple tree development. Your local cooperative extension service should be able to provide you with the name of the fungicide most effective for black rot infections for apple trees in your geographic region and the best time to begin treatment. Typically once you begin fungicide treatments, continue at 10 day intervals until the fruit is full-sized.

http://ctct.essortment.com/blackrot_rkbk.htm

Or, it could be rust: On leaves, pale yellow spots appear on the upper surface during May or June. Spots are up to 1/4" in diameter, turn orange with time, and often have a reddish border. Small black fungal bodies form within the spots and may exude an orange fluid. In time, yellow spots develop on the underside of the leaf. These spots thicken, and during late spring and early summer a number of small, orange-yellow tubular projections appear. These develop into open, cylindrical tubes that split toward the base into narrow strips and curl backward. Infected leaves may turn yellow and drop. Defoliation of rusted leaves is most common in dry summers. On fruit, similar yellow-orange spots appear, usually at or near the calyx end. These spots usually occur on immature fruit and are much larger than the spots on leaves up to 3/4" in diameter. The light green color of the young fruit becomes a darker green around the infected area. The tube-like aecia may form on the slightly raised fruit lesions. Infected fruits are often stunted and misshapen, and may drop early.

Dale writes~
I have several plum trees, hog plums actually, at least that is what we call them in Florida. Can you tell me when and how to prune them, as well as fertilizing along with when and how?

A. Spondias cytherea [S.dulcis] 'Mombin', 'Ambarella', 'Hog plum' is a fast growing, pinnate leaved, large (to 50') tree has plum or small apple sized fruit with a large stone. The fruit are green and hard (when they can be used for pickles in the same way as green mangoes) becoming yellow and soft (but rather fibrous) when ripe. The flavor is variable, vaguely sweet, but with good acid levels. Given the size of the stone and the mediocre flavor, it does not have a great deal to recommend it! Plants do best in heavy loam but tolerate other well-drained soils. Space about 10' apart in rows spaced about 20' apart on sites with good air drainage. This reduces spring frost damage. Because plants most often bear on spurs, lightly thin the outside limbs each spring to give sunlight to those spurs. Remove damaged wood as needed and keep the center of the bush open. Regular pruning will keep the plants vigorous and encourage a good supply of new wood each year. Head plants to about 1' above the ground at planting and prune to 5-6 strong branches in the second year. Head each of them back by about 1/4 their length to promote vigorous lateral shoot growth and to reduce legginess. Fertilize them as you would American plums, that is in early spring as needed to promote vigorous new shoot growth. Treat with a light application of ammonium sulfate (about one pound per plant) before bud swell in early spring. The fruit must be harvested when well colored but still firm, since overmature fruit will drop quickly.

Daniel writes~
I've got a Meyer lemon tree and a Mandarin tree in the backyard. Both are in fantastic condition (Melbourne, Australia). My problem is that we are extending the house and will have to move the trees. What (if any) is the best time to move the trees to a different location? And also how can I best prepare the soil for the relocation?

A. Move the trees very carefully in the fall to midwinter after fruiting is over and temperatures drop. Citrus trees tolerate a wide variety of soils including clay. However, good drainage is essential, as citrus trees cannot survive standing water. Soil rich in humus is best. For heavy or poor soils, dig a large hole and fill back in, half with the best of the original soil and half with a good-quality amendment mix. Plant the root ball high to allow room to settle over time. (The upper roots can be slightly visible.) Straighten out any circling roots before planting. Cut off and remove any broken roots. Do not add fertilizer to the soil; however, apply some to the soil surface after planting. Be sure to tamp soil lightly and water plant thoroughly after planting to eliminate air pockets. Finally, stake the tree until well-established, tying the trunk lightly to a stake while leaving room for the trunk to expand. Green plant tie is a good choice for tying trees to stakes. The best time of day for this task is early morning. Try to keep the roots out of the sun as much as possible. Keep the roots moist and water well once transplanted. Pinch off fruit and blossoms for the first year or two after a new planting to encourage stronger root and branch development.

Lemon, (C. limonia) Meyer's: Fruit small. More cold resistant than other Lemons and very fruitful. Introduced from China by the late Frank N. Meyer.

Mandarin Orange, (C. nobilis deliciosa) - Varieties: Cleopatra. Valued as an ornamental. Used to some extent as an understock. Dancy. Fruit med. and juicy. The most important variety of the group, commonly known as Tangerine, originated in Florida where it is quite extensively grown. King. Fruit large and juicy. Satsuma. Fruit of excellent quality. Temple. Fruit large and juicy. Calamondin. Fruit small, very acid. Used for acid drinks and for high-grade marmalade. Very ornamental and hardy.