Get It Growing: Pruning your trees and shrubs, Part II (How to prune)

When you think of pruning your trees and shrubs, do you envision beautiful shapes but fear seeing distorted, misshapen trees?

For many, the idea of pruning is intimidating. Fear no more! Here are some guidelines to get you started. Remember:

• Prune with a purpose in mind.

• Prune to maintain plant health.

• Prune to control size or improve the plant structure.

In addition, some plants require pruning to encourage flower or fruit production.

What to look for:

Inspect trees and shrubs annually (or more frequently) for pruning needs and use a staged approach:

1. Remove broken limbs

2. Remove diseased, dead or dying wood; remove the limb completely, or cut well below the diseased part

3. Remove suckers from the base of the trunk

4. Where limbs cross or rub, remove the less desirable limb

5. Remove drooping or low-hanging branches unless they are natural to the plant’s shape

6. Remove vertically growing shoots (sometimes called water sprouts). The ideal angle for a branch to join the trunk is 45 to 60 degrees from vertical

Because plants try to maintain a balance between above-the- ground and below-the-ground growth, pruning usually spurs new top growth to maintain balance with existing roots. Removal of too much top growth, however, can overwhelm plant efforts to achieve balance. Therefore, when pruning, reduce the plant by no more than 25 to 33 percent of its total size in one season.

When pruning trees, the natural shape of the tree is usually the best shape for the tree. The most common tree shapes are central leader (Christmas tree shape with a main trunk from which lateral branches develop) and open center (vase shape with three or four main limbs emerging from the trunk at wide angles from each other). In fruit trees, the central leader is typically used for pears; an open center is typically used for cherries and plums. Both central leader and open center are used with apples. With both shapes, space limbs like the spokes of a wheel around the trunk so they do not shade lower limbs.

Two types of cuts are used in pruning, a thinning cut and a heading cut. A thinning cut removes an entire branch or limb where it originates. Thinning cuts open a plant to light and air circulation. When removing a limb, cut close to the outside of the collar (thickened area where the limb joins the trunk).

A heading cut removes a portion of a limb. Heading cuts stimulate buds below the cut, often encouraging excessive and weak growth near the cut. Use a heading cut to influence the way a plant grows, improve the shape of the plant or control the size of the plant, or encourage growth of side stems by making a slanted cut slightly above a bud that points in the direction you want new growth to go. Heading cuts should be used sparingly and should not be used routinely on large branches (greater than one inch in diameter).

These tips will get your pruning efforts off to a good start. Additional information can be found online by searching “pruning trees” at wsu.edu.

Judy English and Jeanette Stehr-Green are certified WSU Clallam County Master Gardeners.