Home & Garden

What to know about pruning

Pruning helps improve the health and beauty of your plants.
Pruning helps improve the health and beauty of your plants. TNS photo

Many gardeners start the season early with pruning. I recently saw Chris Harner of Harner Frams out pruning his apple trees. Why does one prune? The overall answer is to improve the health and beauty of your plants. Winter damage, animal damage, long periods of neglect and erratic growth are all good reasons to prune.

About the only time I will discourage anyone from pruning is when they are trying to control size. If you find you have to keep cutting a plant back to fit it in a particular space, you would be better to move the plant and replace it with one better suited to the limitations of the site. I see little reason to prune every year just to keep a plant small.

One reason to prune is to remove dead, diseased, damaged or insect infested parts of your trees, shrubs or plants. Late this winter, look for broken branches and twigs from the accumulation of snow and ice. Prune these back to a strong side branch to stimulate new growth in that direction. Don’t be tempted to tie, tape or prop broken branches together in hopes they will heal themselves. By this time, the wood has dried and is incapable of growing together again.

As you look for winter damage, check small trees and shrubs for rabbit injury. Look for telltale shortened branches and twigs and gnawed on large branches and trunks. You may also find mouse damage at the base of plants where they have chewed bark. Rabbit and mouse injury are most common in areas where there has been and extensive snow cover most of the winter.

Pruning to treat animal injury is mostly a matter of finishing the job. Either remove shortened stems altogether, or prune them back to a side bud or shoot so new growth can fill in the gaps. If most or all the lower branches have been eaten away, cut away some of the top branches as well to stimulate new wood and growth from roots. In a year or so, your plant should have new branching close to the ground.

Where animals have injured the bark on trunks and stems, evaluate the extent of damage before you prune. If more than half the bark has been chewed from around the branch, it may be too weak to function properly. Cut it off altogether or prune it back below the damage. If you have planted some nice trees on your property and have numerous deer in the area I would strongly suggest putting deer guards around the trunks to prevent the bucks from rubbing their antlers on your nice trees.

If much of the bark on the trunk has been gnawed, the loss may affect the life expectancy of your plant. However, unless all the bark is gone, you may want to keep the plant and see if it survives. The greater the bark injury, the more likely you plant will have problems in the future.

Since the irregular pattern of animal damage will not allow wounds to heal properly, speed the healing process by shaping the wound. Cut away all irregular edges of bark. The shape of the “new” wound should be elliptical and parallel to the line of the damaged branch or trunk. You may have to cut away some good bark, but the clean wound will heal much faster than if let alone.

If you have discovered serious damage to large trees from wind, ice or snow, let a professional arborist help. Split trunks and large broken limbs high in trees need specialized equipment to repair. Don’t be tempted to do the work yourself. Large limbs are much heavier than they appear and can cause you and your property injury if not handled properly.

Bill Lamont is a professor emeritus in the department of plant science at Penn State and can be reached by e-mail at wlamont@psu.edu.