Q.I Would Like To Shorten My Boxwoods. How Many Inches Are Safe To Cut?
I have 4 the same size (slightly average 6 ft tall) and they have grown to block the windows and brick front. I would like to take them down 18-24 inches which would open the tops. Is it safe for the plant to take that much off and will the center regenerate?

Certified GKH Gardening Expert
A good rule of thumb is to never take down more than one/third of the shrub, so you should be fine taking them down up to 24 inches. Try to make your cut on the long branches just above a bud. The interior should be trimmed in the same way and will regenerate if there is light and air moving through the bush. You should probably wait on this until spring, but clearing and cleaning out dead branches and leaves can and should be done any time.
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/trimming-boxwood-bushes.htm