My globe cedars in TX are 20 feet tall. How do I prune/ trim them?
Globe Cedars, Thuja occidentalis, tolerate pruning as long as it is not too severe and that you do it at the right time of year. Spring is the best time to prune, before the buds have developed. During the warmer summer months your cedars produce buds, that will sprout as new growth next spring. If you prune during the summer months you can stress the trees into producing more buds, depleting their winter energy stores and increasing the risk of winter die back, which they may not recover from.
When pruning cedars, only remove green foliage and take care to leave some of the current years growth. This can be identified as it has green stems. Cedar stems brown off with age. Cedars struggle to rejuvenate from woody tissue, so if you prune into the brown stems you may not have any regrowth in spring and the affected branches may die.
Like all pruning, it is best to use sharp tools, which produce clean cuts and minimize damage and infection, and to clean your tools after use.