Pruning trees is important for their health and good looks. But if you do it wrong, a tree may be ruined. Here are four common mistakes many people make—and how to avoid them…
• Mistake: Using the wrong tool. A surprising number of gardeners try to prune using regular garden clippers. They end up tearing at the wood, which makes a torn or shredded mess that can be difficult for the tree to heal and thus invites illness and insects. The thicker the branch, the more heavy-duty the tool should be. Long-handled clippers called “loppers” offer reach and leverage and, depending on size and length, can handle branches up to two or even three inches thick. If the branch is thicker than that, use a pruning saw. Never cut with a carpentry saw, which cuts in only one direction and tends to gum up.
For high work, use a pole pruner—a pruning saw mounted on a long pole.
• Mistake: Cutting in the wrong spot. When cutting off smaller branches or trimming back the slender ends of big ones, slice neatly back to just above a bud or side branch (within one-quarter inch or so is the best spot to inspire new growth below). Make slanted cuts at about a 45-degree angle—slightly angled away from the bud, open wood facing up.
When using a saw to remove a large or heavy branch, don’t attempt to cut it in one fell swoop. Begin about one foot out from the trunk. Make a straight undercut halfway up through the branch. Next, an inch farther out from the trunk, make a second cut—cut until the branch breaks free. Trim off the foot-long stub afterward—you’ll be able to do neater work with the full weight of the branch now gone. Prune just above where the branch meets the trunk, as cuts flush with the trunk have a hard time healing.
• Mistake: Removing too much. Removing too many limbs reduces a tree’s leafy canopy. In hot climates, sudden sunlight exposure can scald unsheltered bark and foliage. Also, a dramatic reduction in foliage upsets a tree’s photosynthetic processes, and the tree will struggle to produce enough food.
The worst case of overzealous cutting is “topping,” which involves taking the top off a tree. At best, such beheading spoils a tree’s appearance—at worst, it ruins its health because it has lost too many leaves to sustain itself. If a tree is simply too tall for its space, your best bet may be to remove it altogether.
• Mistake: Bad timing. Proper timing is important, but there is no one rule of thumb. Flowering trees should be pruned right after their blooms start to fade. If you wait, you’ll be cutting off the new buds forming for next year’s show. Trees that produce fruit or berries need to be pruned much earlier—in late winter or just as growth starts—otherwise, you’ll interfere with the harvest. If you cut back an evergreen in the late spring, it will bleed a lot of sap, which is unsightly. Instead, prune evergreens when they’re not actively growing, typically in the late summer, fall or winter.