When to trim arbrovitae
I have a arborvitae hedge, the hedge is about 12' to 16' tall. I would like to trim the top at least 4' to 5'. Is that too much to trim at one time?, and can I trim them right now in Dec or Jan ? Or when would be a better time?
Hennepin County Minnesota pruning arborvitae
The recommendation is to prune off no more than 30% in one season. The trees depend on their needles to provide adequate food. Loosing more leaf or needle mass stresses the tree. You are suggesting 50%-75%, try for closer to 40% if you feel you much prune them severely. I would wait to prune until Feb or Mar. so you have the benefit of a wind break and the birds have shelter this winter.