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Published January 31, 2009, 12:00 AM

Prune fruit trees now for higher quality later

The objective of growing apple and other fruit trees is to maintain production of high quality fruit on a continuing basis.

By: Jim Stordahl, DL-Online

The objective of growing apple and other fruit trees is to maintain production of high quality fruit on a continuing basis.

The two primary reasons that trees do not produce high quality fruit are improper pruning and lack of effective insect pest control. Because late February, March and early April are the recommended times of the year to prune fruit trees, some information on properly completing that task is timely.

First of all, it is important that fruit trees be pruned annually. Annual pruning allows you to limit pruning of bearing fruit trees to removal of weak unproductive branches, to remove excess branches thereby improving light penetration, to reduce tree height, to facilitate fruit harvest.

Begin by removing water sprouts that may be growing on the trunk and major limbs of the tree. Water sprouts are succulent vigorous shoots that generally grow straight upward from the trunk or limb. They use water and nutrients with little or no fruit production. Remove all broken, damaged or diseased branches. Remove the weakest of crossing branches and those growing close together.

Remove or head back limbs that are growing downward as they will often break from the weight of the fruit. When heading back a branch, make the cut just before an upright pointing spur or bud so that the new growth with grow upward. The upper branches should not be allowed to grow longer than the lower branches as the shade they produce will reduce the productivity and quality of the fruit.

When it is necessary to reduce the height of a tree that has grown too tall for convenient harvest, cut the taller branches back to the place where they originate from the trunk or join with another branch. Do not top a tree by giving it a “crew cut,” that is, cutting all the branches randomly at a certain height. This will result in a lot of weak sucker growth that uses a large amount of nutrients without producing fruit and breaks easily.

When pruning, it is important to use sharp, clean tools that are made specifically for pruning. Make all cuts smooth and close, but do not flush cut. The cuts should be made just beyond the branch collar swelling. The branch collar is the narrow ring of stem tissue that grows at the base of the branch. Do not, on the other hand, leave stubs as they will encourage decay and canker.

Finally, do not over-prune trees that have been neglected. Leaves are the food manufacturing organ of the tree and reducing too much of the leaf area will result in reduced vigor and fruit production. In addition, heavy pruning will stimulate new succulent growth that increases hazard of fireblight in apple and pear trees. A rule of thumb is to limit pruning to the removal of no more than one-third of the total wood of a tree in any one year.

To have your own copy of our bulletin, “Pruning Trees and Shrubs,” which has greater detail and nifty illustrations, contact the one of the finer Extension offices near you. If you have Internet access, you can print your own from the web site, www.extension.umn.edu.

For more information on this topic, contact me at the Polk County Extension office in McIntosh at 800-450-2465, or at the Clearwater County Extension office on Wednesdays at 800-866-3125. If e-mail is your thing, contact me at stordahl@umn.edu. Source: Carl Hoffman, Stearns County Extension.

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