Would you know of a good hedge to plant around the base of two large Maple trees?
DeGroot has the proportions you desire but it is sheer luck that deer haven't dined on your Holmstrup. Unfortunately there are no deer resistant arborvitae. Deer will eat different plants at different times. Yes, boxwood quite often suffers from winterburn. It is a combination of not enough moisture going into winter and drying winter winds. I don't quite understand that you are trying to do with a hedge. Are you actually talking around the base of the trees or farther out? Maple trees provide great shade but as a consequence only shade loving plants will grow there. That also is dry shade as the tree roots catch the moisture first. The best thing for under your maples is wood mulch. You can put in a few shade loving perennials for color.