It is best to trim and prune hemlocks in early spring or late winter before the active growth period begins, trimming only what is necessary. Hemlocks will sprout vigorous new growth once trimmed and pruning during the active growth period may prevent the tree from going dormant when it needs to.

When should you prune hemlocks?

A: Hemlocks tolerate trimming and shearing better than most evergreens. The ideal time is the end of winter, just before new growth begins. You could trim in winter, but the more you cut, the barer it'll look for a longer period of time until new growth resumes again in spring to fill in.

How do you prune overgrown hemlock?

Select the branches before you start trimming so that you do not over prune the tree accidentally. Then make your pruning cuts just above the needle whorls. Hemlock trees will grow new branches from the needle whorls, and pruning just above them will ensure that the new branches come in properly.