Arbavitae

Asked July 20, 2018, 7:48 PM EDT

My arbavitae are very tall and some are starting to bend over quite far. What can be done short of chopping them down? I'm afraid if we get any snow this winter they might snap. Help please!!

Douglas County Oregon

1 Response

Arborvitaes are narrow-leafed evergreens that respond best to selective thinning and shaping cuts to maintain their natural habit as opposed to overall shearing. Thinning cuts remove branches and twigs to their point of origin, or you can prune selected growth back to a bud to promote more compact growth. Upper branches that shade lower branches are thinned to allow sunlight to reach the lower branches. Do remove crossing branches and those that are growing toward the center of the plant, but don't trim a branch back to bare wood because it may not produce new growth.

If you're using arborvitaes as a hedge, keep the bottom of the hedge wider than the top to allow light to penetrate to the base.

If your arborvitae is overgrown, don't try to cut it back more than 20 percent or it may not develop a new leader or terminal shoot. Topping is often done when a tree's height becomes problematic. When the top of an arborvitae is cut off, however, it creates a very flat and unsightly appearance. No new growth will occur once the upward growing branch tips have been cut, and no horticultural benefit exists for topping an arborvitae. The only time that topping may be beneficial is in an emergency when the top of a plant has been damaged.

Arborvitaes that are a couple of years old are more forgiving of cuts than an old tree. You can cut back into wood that is a year or 2 old, and the tree will likely grow it back. However, in older trees, it's less likely to grow back. Arborvitaes really don’t need much pruning in general, so you should mostly prune to keep the tree's natural shape.

Hope this helps!