Tree pruning. (ISU photo)
It may be the dead of winter, but a tree expert from Iowa State University says now could be the best time of the year for homeowners to prune their trees.
Professor Jeff Iles , chair of the ISU Department of Horticulture, says February into March is perfect for trimming those wayward limbs. “This is a good time, for one, because you can see the architecture, you can see the bones of the tree without the foliage getting in the way,” Iles says. “Everything is in the open, you can see what you’re doing. Of course, without the leaves and because you can see the architecture of the tree, you can see flaws, things that should be corrected.”
Pruning can help to improve the health and structure of the tree. It can also remove growth that may interfere with nearby structures, or to prevent safety hazards for people, pets and livestock. In addition to having good visibility of the tree’s “bones,” Iles offers more reasons why wintertime is a good time for pruning.
“You can make the pruning cut now and that wound — and it is a wound — will begin to close quickly as growth commences in the spring,” Iles says. “Finally, there is very little chance of insect or disease transmission when you prune at this time of the year.” There are different schools of thought about exactly where to cut off a limb. Iles says to examine the tree carefully before making a cut, and preserve the “branch bark ridge” and the “branch collar,” for the best wound closure.
“Back in the day, you might remember that pruning cuts were always made flush with the main stem or with another branch and we’ve learned that that was a bad policy,” Iles says. “Now, we try to look for landmarks on the tree, places where branches should be removed that don’t injure the tree.”
Visit any hardware or home improvement store and you’ll find a range of products which claim to be ideal for brushing or spray-painting onto the tree’s wounds after pruning. “I can’t think of any of those that do any good,” Iles says. “They don’t hasten the closure of the wound. They don’t protect the wound. They don’t help the tree get better any quicker. What we advocate is making the proper pruning cut at the right time of the year and let the tree handle that wound, which it will do quite nicely.”
Pruning should typically focus on younger trees as it can be dangerous to try pruning long, heavy limbs on mature trees. That’s something Iles says we should leave to the professionals.