Shaping the Future
Thursday, March 15, 2007
Before the leaves appear this spring, do yourself a favor: Go and look at any deciduous tree you have planted in the past three or four years.
Thoughtful structural pruning now will produce a tree that will be healthier, stronger and more attractive than one left to develop unaided. This month, we pruned two young trees with their future in mind.
We first tackled an Eastern redbud planted last spring as a six- to eight-foot specimen. It is typical of many immature ornamental and shade trees that need a strong single trunk, the removal of conflicting branches and the establishment of a handful of well-spaced limbs that will grow to become major "scaffold" branches. Like a lot of young trees, it had lost its central leader and needed someone to find a substitute.
The second tree was a crape myrtle planted as a six- to eight-foot specimen two years ago. We chose the crape myrtle because it is typical of low-branched or multi-stemmed trees such as dogwoods, serviceberries and deciduous magnolias. Moreover, the crape myrtle has become a widely popular landscape tree that cries out for formative pruning. The common variety Natchez grows to 30 feet and casts dense shade with its broad canopy. When people realize this, they often resort to heading back the trunks to a stump, an old-fashioned technique now generally considered bad for both the tree and the eye.
But by shaping a tree when it is young, you are shaping its future. You won't be reacting to its waywardness 10 years from now, when it is too late for the best care of the plant.
The best time to assess the branch structure of a tree, however, is at the nursery. If a tree has poor branch structure and competing leaders, move on to another individual.
Trees planted this spring should not be pruned until next winter, except for trimming broken branches.
If you do decide to tackle formative pruning, allow at least an hour per tree. It is a slow, methodical process. As you remove each branch in succession, you get to see other obvious candidates for pruning. Don't cut a branch back to an arbitrary stub. Either remove it entirely or cut it back to a bud facing the direction you want the stem to grow. View the plant from all angles between cuts, and be conservative. You should take two or three winters to fully complete the process, to avoid removing too much of the canopy in one year.