Q: boxwood are Getting to tall how much can i trim and when?
I don't recommend taking off more than 20 percent of the shrub in a single season. Cut off all the leaves on a branch and it will not recover. The best time to prune is June after the new growth has emerged. Prune later in the season and the new growth may not harden off leaving it vulnerable to summer scorch and winter kill. Best And Happy Yardening, Nancy.