You can save yourself some money, your plants will be healthier and look better for it, and there’s a feeling of satisfaction in a job well done.
Katrina Lewin, a horticulturalist at The Morton Arboretum in Lisle, Illinois, spends much of her time pruning—50 percent of her workdays during the winter months, she says.
There are some basics that every gardener or homeowner should know. Lewin explained them as she applied her skills to a witch hazel that needed some work.
Tools of the Trade
Lewin relies mostly on three items: a long-handled lopper, a hand pruner and a folding hand saw. The first two should have bypass blades (they operate like scissors) that should be sharpened once a year or so, depending on use. The lopper requires both of your hands; the hand pruners (or shears) need just one hand. The folding hand saw, such as Felco’s F-600 (we found one on Amazon.com for $30), looks small but is a workhorse.
For trees, you’re usually looking to create a dominant, central leader—a main stem growing straight up to define the vertical structure—and which will result in a stronger tree. For shrubs, you want to create a more pleasing shape and/or to spread the branches out to create a better air flow for the plant.
For trees, winter and late fall are the best time; Lewin likes to be done by late March. “You don’t want to prune when insects are active; you don’t want to create wounds that will attract them,” she says.
For shrubs, “it depends on when they flower,” she says. “Spring-flowering shrubs (should be pruned) right after they flower (and before) they’ll be setting their buds for the next spring. Summer-flowering shrubs can be pruned in the fall or winter dormant season.”
Lewin says she generally has a set of steps or priorities. For trees or shrubs, the first step is to cut away dead or damaged branches. Then thin out congested areas. With trees, next go for any branches that are competing with that central leader. For a shrub, take out crossing branches and do some shaping for symmetry.
Take your time, especially with trees. While a shrub sends up shoots from the ground all the time, trees are more permanent. If you botch the job and make a bad cut at that central leader, the tree will look like … well, like you botched the job.
For tree branches, cut just beyond the branch collar — the natural swelling an inch or two away from the main leader; do not cut flush to the tree. On a branch, cut at a branch union, not mid-branch — “otherwise you’ll have a stub that will just die,” Lewin says.
The Arboretum tries to prune each tree every year. Young trees get a lighter trim, and no tree should have more than 20 percent of its live branches trimmed in a year. For shrubs, Lewin says, “you can be very aggressive. There are some that can tolerate being cut to the ground and they’ll come back.” Also, if you’re working on a shrub and thin or cut the foliage at the bottom, leave some in case something happens to the older branches higher up.
Pruning Know How
Safety measures and proper sanitation principles (such as keeping the tools clean to prevent introducing disease or infection to the plants) are useful. For additional information on these topics, and more:
—These websites have good information on pruning trees and shrubs: The University of Illinois Extension offers detailed advice on specific pruning tasks, including roses. Go to urbanext.illinois.edu (click on Hort Corner, then Trees and Shrubs). Other useful sites include the U.S. Forest Service (na.fs.fed.us, then type “prune trees” in the search field; information on shrubs is here too) and Fine Gardening’s website (finegardening.com, then click on “How To” and choose “Pruning” from the drop-down list).
—”The Pruning Book” (Taunton Press) by Lee Reich. The second edition, released in 2010, is filled with useful photos and covers just about any topic or concern that will pop up.
©2011 the Chicago Tribune