when is the best time of year to prune arborvitaes?

Question

i want to cut the tops back a little to stimulate side growth.

Answer 1

Here's a quote from a site that provides excellent advice on arborvitaes and about the time of year to prune them;

"The best time to prune arborvitaes is just before new growth begins in the late spring but do not cut it back beyond the green foliage. Doing so will condemn that spot to be bare forever. This is perhaps one instance where an electric hedge shear could be put to good use!"

Answer 2

early spring