Gardening: Prune fruit tree according to use in garden

For Ben Kappen of Northwest Plant Health Care, pruning residential fruit trees, especially those that have been let go for several years, begins with the decision of whether you want the tree as an ornamental or for its fruit production. The decision you make will determine the style of pruning you will need to do.

If you want to maintain it as an ornamental tree, Kappen recommends using the same types of pruning you would use on other ornamental trees. Using International Society of Arboriculture guidelines, start by removing dead limbs, followed by rubbing or crossing branches and those that join the trunk at a steep, upright angle. If the tree has more than one tall dominant leader branch remove all but the tallest one.

“We are looking to develop the natural structure of the tree but not specifically moving into fruit production pruning,” says Kappen. Don’t round off the tree into a ball or cut or top the tree into a flat shape.

If you want fruit production, the trees need to be pruned so light can reach the inner branches and to make the fruit easy to pick.

For a vigorous apple tree this may mean removing 40 percent to 50 percent of last year’s leafy growth, cutting back long limbs to keep the short fruit spurs within reach and to keep a heavy fruit load from breaking branches. It also stresses the tree into putting more energy into fruit production. Because of the stress to the tree, only healthy, vigorous trees should be considered for the process.

Once the tree has been reclaimed, prune on a yearly basis to keep pruning cuts small and the subsequent stress to the tree low. If an apple tree has a lot of small fruit, consider pruning out some of the short fruit spurs out.

Regardless of the style of pruning you choose, be sure you cut branches properly. Look for the branch collar, a ridge on the branch just outside the trunk and cut back to just above it but not into it. This allows the tree to heal quickly. If the branch is over an inch in diameter, undercut it a ways out from the trunk, then cut it off and then trim close to the branch collar. This will keep the bark from tearing when the limb falls. Don’t use wound sealants as they can seal in moisture that can promote undesirable bacteria and fungal growth. Clean your tools with a 10 percent bleach solution before you go to the next tree.

To reduce the growth of water sprouts that grow straight up from a limb, leave a quarter of them on the tree each year and head them back to less than ten inches. This helps the tree keep its root-to-branch balance and helps reduce future water sprout growth.