How to Prune a Tree
An arborist's rules on how to shape up a small ornamental tree to make it more attractive and healthy
We all know proper pruning can enhance a tree's health and beauty. But tangled branches that don't look like the neat illustrations in books can be daunting. So where do you begin?
First, be sure it's a job you can handle. A small ornamental tree 12 to 25 feet tall—such as a flowering cherry, magnolia, crab apple, or Japanese maple—is one you can tackle yourself. (Bigger trees that require chain-saw and ladder work are best left to a pro.) Then be sure you understand a few key principles.
"Pruning stimulates growth," says Bill Pollock, co-owner of Arbor Services of Connecticut. "The goal is to encourage the tree to grow strong, healthy branches headed in the right direction." So Pollack makes health-promoting cuts first, removing competing, misdirected, and weak branches. Then he prunes to enhance the tree's natural form. "A magnolia has a graceful, open habit with main branches that grow up and out, and sweeping lower branches," he says. "You want to remove branches that don't look like a magnolia." A common mistake is to "top and shape" by clipping the ends of branches. "Healthy shaping is done mostly from the inside," he adds. The best time for the kind of remedial pruning an established, long-neglected tree (like the one in this story) needs is winter or early spring, when active growth has not yet begun. Bare branches allow you to stand back and really see what needs to be removed.
Shown: Arborist Bill Pollock stands back and takes a look at his work-in-progress from various angles, assessing the tree's balance. "Don't get carried away," he advises overzealous pruners. "Remember, there's always next year."
Plan the Biggest Cuts First
Here, Pollack has marked different problem branches with colored tape to illustrate his approach. Keep in mind that you should never remove more than one-third of the tree's growth at a time. A vertical internal stem, with orange tape, competes with established leaders (the tree's main stems) and sticks up too high. Pink tape marks rubbing branches that can injure protective bark. White tape indicates either damaged or broken branches, or dead ones, which are dark and shriveled. Yellow tape marks vertical shoots, called water sprouts, that crowd the tree's interior. Pollack tackles the biggest cut, on the large stem, first. Using a pole saw and cutting in increments to prevent tearing, he prunes the stem back to a lateral branch to reduce its height and encourage additional branching.