These plants can tolerate heavy pruning, but usually only need.
Like all coniferous evergreens, arborvitae require very little and infrequent pruning, but can tolerate some trimming for grooming or shaping purposes.
In the same spirit, you could also trim holly, evergreen magnolia, spruce and yew at this time.
When the arborvitae is badly overgrown, you should trim it in stages to avoid cutting down to bare wood, as the tree cannot regenerate green foliage growth at Missing: Greenwood IN. Dec 15, Because arborvitaes grow continuously during the growing season, you can prune them at any time through mid-summer. Topping arborvitaes, however, negatively affects the trees' Missing: Greenwood IN. Dec 10, Like most evergreens, arborvitae should be trimmed while it is dormant.
This is roughly from about Thanksgiving to St. Patrick's Day. Many gardeners like to prune these evergreens Missing: Greenwood IN.