Cass County Extension
Pruning Fruit Trees
Pruning fruit trees is necessary to develop a strong structured tree, to maintain tree vigor and control size, and to produce abundant high quality fruit.
When to Prune
The proper time to prune is in early spring when the danger of severe cold weather has pasted and before new growth occurs. However, suckers and broken, dead and diseased branches should be removed at any time. Sterilize pruning tools between cuts with a 10% bleach solution (1 1/2 cups bleach to 1 gallon water) when pruning branches infected with fireblight (see circular PP-454 revised, "Diseases of Apples and other Pome Fruits"). Pruning paint or a wound dressing should be used on trees which can be infected with fireblight. Either asphalt-water emulsion or shellac makes a good wound dressing. Latex (water base) paints are also satisfactory.
Pruning at Planting
Newly planted fruit trees should have only one leader (upward growing shoot). If there are two or more leaders, they form narrow `V' crotches where they join. These crotches are weak and will break in the wind or when loaded with fruit. Potted trees which haven't been pruned and bare root trees need to be pruned when planted. The leader should be shortened and the side branches cut back to one-third to one-half of their original length. Remove side branches which have narrow crotch angles with the trunk or branches which are less than eight inches from other branches. The lowest branch should be at least two feet from the ground and if possible on the southwest side of the tree. This will provide shading in the future and reduce sunscald damage to the trunk.
Pruning Immature Fruit Trees
A fruit tree which has not started to bear fruit requires little pruning except to select main (scaffold) branches. This selection of scaffold branches should be done as soon as possible. Don't prune any more than absolutely necessary. Pruning will retard growth but it will also delay fruiting. The four to six scaffold branches should be 8-18" apart, evenly distributed around the trunk, and have relatively wide crotch angles (at least 45 degrees) with the trunk. The branches on plums, apricots and sour cherries can be slightly closer together. Branch spreaders can be used to widen the crotch angles on small branches.
Pruning Fruit Bearing Trees
Light annual pruning is needed to control tree shape and size as well to open up the tree to allow for better sun penetration. Biennial bearing trees such as apples can be pruned heavier in the year when a heavy crop of fruit is expected. When the fruit tree reaches a desirable height, remove the leader just above a well placed outward growing lateral branch.
The following types of growth should be removed when
1. Watersprouts and other vertical growing shoots
2. Branches growing in toward the center of the tree
3. Weakest of crossing over or rubbing branches
4. Downward growing or drooping branches
5. Weakest of closely parallel growing branches
6. Long slender growth in the inner part of the tree
Apples - Fruits are usually borne from fruit buds on short spurs two years old or older. Spurs may live 15-20 years and tend to bear fruit every other year. When fruit sets, new growth comes from the side of the spur causing it to develop a zigzag growth pattern. Non fruiting spurs are straight. When pruning, be careful not to remove fruiting spurs. Pruning paint, shellac or latex (water base) paint should be used to seal pruning wounds as a deterent to fireblight.
Pears - Trees are pruned similar to apples but tend to be more upright growing. Branch spreaders are a good method of developing wider crotch angles. Pears are slow to began fruiting and produce their fruits on spurs. Because of their susceptibility to fireblight, pruning wounds need to be treated as noted above for apples.
Plums - Bear the majority of their fruit on vigorous spurs on wood two years or more old. Avoid heavy pruning which stimulates watersprout growth. A light thinning out of small branches and twigs is needed each year to open up the tree and prevent declining fruit production in the inner area of the tree. Older tree which haven't been properly pruned bear fruit only on the outer 2-3 feet of each branch.
Cherry-Plums - Small, short-lived trees which bear good for the first few years with little pruning. When the trees are young, prune back to stimulate new growth and reduce breakage from heavy loads of fruit. Each year older trees should be pruned to remove old wood and encourage the growth of new fruiting shoots. Two to four year old stems are the most productive.
Apricots - Most of the fruit is produced on short spurs which are productive for up to three years. Annual thinning-out of upper branches is needed prevent inner shading and to stimulate the development of new fruiting spurs.
Sour Cherries - Produce some fruit on annual shoots but most is borne on spurs. Light thinning out of upper branches is needed to keep the tree open and to allow for good sun penetration.
Renovating Neglected Trees
When pruning neglected fruit trees, it is not necessary or possible to correct all errors in tree structure due to the lack of pruning in the past. Complete rejuvenation may take several years of heavy pruning. Do not remove more than one-fourth of the top growth in any one year. Fertilizer should not be applied during years of heavy pruning to reduce the amount of regrowth. The main objectives in pruning neglected fruit trees are to reduce tree size, thin out branches and most importantly increase fruit production and quality.
Tree size is reduced by lowering the height of the tree and cutting back the lateral branches to obtain the desired width. When reducing tree height, no more than four to five feet of growth should be removed in one year. The top should be removed just above an outward lateral branch. Water sprout removal may be necessary in subsquent years.
Thinning out of undesired, large branches should all be done at one time. However, if more than four large branches need to be removed, remove half one year and half the next. After removing the unwanted large branches, remove smaller low hanging branches and dead, diseased or broken branches. As a final step thin out the smaller branches in the tree. Remove underhanging branches, vertical growing shoots and other weak growth. The thinning out process will open up the tree for better light penetration, the development of fruiting wood and finally more and better quality fruit.
|Todd Weinmann, Extension Horticulturist & Master Gardener Coordinator|
|Phone: (701) 241-5707|
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