One of the best things about this giant arborvitae is its low maintenance. Green Giant doesn't need pruning, you can simply let it grow. You need only trim your Green Giant Arborvitae to the form you want--and most gardeners find that shaping this already-shapely arborvitae isn't necessary. However, if your goal is perfectly-uniform hedges, it may make sense to lightly prune your Green Giant Arborvitae. If you want to prune your hedges for aesthetic reasons, be sure to prune in the spring or summer before cool weather sets in, giving your arborvitae time to harden off where it has been pruned before winter's first frost. Be sure not to cut the limbs back entirely, as bare limbs may not "green up" again after a harsh pruning. Keep your cuts within green wood, so that the plant will be able to fill itself back in. Keep a shape in mind as you prune, and be sure not to cut the bottom of the arborvitae deeper than the top. Remember, these attractive arborvitae grow in a naturally pleasing, pyramidal shape--allow them to keep that shape by not over pruning.