Normally, we begin pruning trees and shrubs in late November or early December, just after the first frost. But in years with abnormal weather, your landscape may experience greater mortality than in previous years and you may want to begin pruning earlier.
The general rule for pruning trees is once every four to seven years, or you can use my simple rule: every five years or during a year ending in 0 or 5. It’s fairly easy to remember!
Always begin with a plan. Start with plants that have dead branches. Look at the buds and the bark. Dead branches will not have any full buds at the tips or will have loose or sunken bark. If these are not readily apparent, scratch the bark with your fingernail or pocket knife. A living branch will be green beneath the bark. A dead one will not.
Next, remove twigs and branches that may be diseased or infested with insects. Diseased branches will be discolored or have sunken bark. Twigs and branches infested with insects will have pitted or discolored bark — or insect eggs or body parts will still be evident.
It's always important to remove the entire dead or infested branch. Leaving a stub does not benefit the tree. Prune it back to a main trunk or major branch of equal or larger size. Of course, topping (pdf) — or removing all the branches until you’re left with several big stubs — is always discouraged for both trees and shrubs.
Finally, for shrubs and perennials, a very light reduction of the green top foliage and thinning of the interior branches will maintain the balance of shoots to roots. And, this will induce vigorous new growth next spring to help produce new roots. Prune no more than 20 percent of the entire green plant at this time. Flowering perennials can be pruned to nearly the ground during the first week of March.
Pruning trees and woody shrubs is an essential job of landscape maintenance. The dormant season is the proper time to do it for both the tree and you.
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About our expert
Mark A. Peterson is a conservation project coordinator for San Antonio Water System. With over 30 years of experience as an urban forester and arborist, Mark is probably the only person you know who actually prunes trees for fun. When not expounding on the benefits of trees and limited lawns, you’re likely to find him hiking San Antonio’s wilderness parks or expounding on the virtues of geography and history to his friends.
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