To Prune or Not to Prune? That is the Question

By Carolyn R. Casey, Fairfax Master Gardener Intern
For some people, the idea of pruning can be intimidating. But it does not have to be. Pruning is not difficult if you understand the basics. To prune successfully you need to be aware of why you should prune, when to prune and how to prune. Correct pruning is essential for keeping trees and shrubs healthy. It can help you manage the size of your trees and shrubs. Every year, you should examine the trees and shrubs in your yard to decide whether they need to be pruned. Once you decide, you should only prune one-third of the plant each year until you achieve the desired shape. This is called the “one-third rule,” and it provides a basic guide to pruning established and mature trees and shrubs.

It is important to note that pruning is typically done in stages. Step back from the plant that you want to prune and examine it. Where does it need to be pruned? After each cut you will want to step back and look at your plant again. Are you achieving the desired shape?

Pruning Strategies

It is important to prune all dead, diseased and damaged branches as soon as possible after you notice them. Prune out downward growing branches. When you have two branches that cross each other, keep the dominant branch or the one that is going in the best direction for future growth. Prune out any branches that are larger in diameter than the trunk. Typically, you want to remove them before they become this large. Otherwise, you may create a large wound from pruning that does not seal completely. Remove suckers that are coming up from the roots. Also, prune out the small vertical branches called water sprouts that grow from a pruning wound, crack or other damage to the tree.

Pruning at collar

Pruning at collar

Prune close to the branch collar at the base of the limb. The branch collar grows from the stem tissue around the base of the branch. Make pruning cuts so that only branch tissue is removed. Be careful to prune just beyond the branch collar, and don’t leave a stump. If the branch collar is left intact after pruning, the wound will seal more effectively.

Newly planted trees and shrubs need as many healthy leaves as possible for photosynthesis and food production for use in establishing roots. For the first growing season, prune out only the dead, diseased or damaged branches. This helps young plants to develop strong structures. Do not cut back the main leader of a tree or