Begin shaping boxwood at a young age. Boxwoods should be wider at the bottom and taper as you move up to the top. This allows for better light in the foliage and creates a more natural appearance.
Shear boxwoods each year for the first three years. Run hedge clippers along the plant after each flush of growth. Let the growth finish before shearing so that you only have to do this once per season. Shearing will promote new branch growth. Create the desired shape by cutting off a little at a time, working in one direction. Step back and eye the plant to see where more needs to be removed.
Shear boxwoods after the first few years only to maintain the desired shape. Too much shearing will cause the outer foliage to be so dense, it shades the inner foliage from the sun. Avoid shearing the plant in the late summer.
Prune boxwoods for a more selective way of shaping the plant. Select diseased, weak and dying branches. Cut them off where they meet healthy branches. Remove wayward branches until you get the desired shape. This creates a more natural form than shearing.
Prune the shrubs in the spring to eliminate wood that was damaged by the cold temperatures in the winter. Remove older branches to let more light in and encourage the growth of new branches.