The best time to prune evergreen trees and bushes is in the early spring months of March and April, right before new growth starts. Evergreens should be sheared in June or July, allowing the trees or bushes to generate new buds for the following year.
Pruning and shearing serve two distinct purposes. Pruning, or cutting off at the base of branch, allows for a new branch to develop in its place. Pruning makes a fuller bodied shrub or tree. Shearing means trimming the external parts of the shrub or tree in an effort to make it more uniform in appearance. Both pruning and shearing annually is necessary for maintaining healthy and attractive evergreens.