The first major step in achieving a smooth hedge leads to the second. An accurate measurement makes the cutting of the hedge much easier. The longer blade on the trimmer helps, too, making it easier to connect the top measurement with the bottom one.
I am the only one who prunes the boxwood (Buxus microphylla ‘Koreana’) hedge at the Morton Arboretum, in Lisle, Illinois. The hedge is the only formal garden at the arboretum, and I enjoy the rigid, neat, and precise trimming it requires. Maybe it’s my background in art that allows me to appreciate its design purity. Or maybe it’s that my shearing system seems to work right every time.
You certainly don’t need a degree in art to want a nice, smooth hedge, and this system, which I’ve used in my nine years of pruning the boxwoods, is one anyone can use to achieve the same clean, formal look our hedges have.
The straight edge that is the hallmark of the formal hedge depends most on what you do before you cut. Accurate measurements and well-placed stakes are the key. I recommend shearing the hedge in an inverted keystone shape, narrower on the top and wider at the bottom. At the arboretum, we shear our boxwood hedge to 24 inches wide across the top and 36 inches wide at the bottom. This slight 6-inch slope is both attractive and healthy, as it allows all branches to get maximum sunlight. The shade that’s created beneath it is an added benefit, because it cuts down on weeding and watering.