Pruning trees and woody shrubs is an essential part of landscape maintenance. Right now in the dormant season is the prime time to prune.
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 trunk or branch 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. You can also use my simple rule: every five years or in a year ending in zero or five. It’s easy to remember!
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.
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. Make sure to remove the entire dead or infested branch. Prune it back to a main trunk or major branch of equal or larger size.
Finally, thin the green top foliage and interior branches of shrubs and perennials. This will help maintain the balance of shoots to roots and encourage vigorous new growth next spring to help produce new roots. Prune no more than 25 percent of the entire green plant.
Of course, topping (pdf) — removing all the branches until you’re left with several big stubs — is always discouraged for both trees and shrubs.
Pruning trees and woody shrubs is an essential job of landscape maintenance. The dormant season — late November, December, January and early February — is the correct time to do it.