Pruning class helps tree owners prepare for spring

IRONWOOD — With the growing season approaching, the University of Wisconsin-Extension, Gogebic County Conservation District and Range Master Gardeners held a tree pruning workshop at Gogebic Community College Saturday.

Darrin Kimbler, a horticulture educator with Iron County’s UW-Extension office, gave a presentation on pruning and why it is important.

There are multiple reasons to prune a shrub or tree, according to Kimbler.

He explained pruning involves the strategic shaping of a plant for a variety of reasons; including improving its strength, longevity, fruit and flower capabilities and health as well as managing its shape or size.

Not all trees and shrubs need to be pruned, Kimbler said. He explained that while any tree planted to produce a crop needs to be pruned; plants intended purely for landscaping may not need pruning, depending on how natural of a look is intended for the property.

It’s generally best to prune during a dormant period, Kimbler said.

“I like to prune in late winter, early spring; that way I can prune out any winter kill that may have happened, as opposed to prune out in the fall,” Kimbler told the Daily Globe after the event. “During the dormant season, it reduces the opportunity for disease and insects to infest the wounds.”

He discussed the best ways to ensure the fresh wounds created by pruning don’t get infected, including sterilizing pruning shears by dipping them in bleach before each cut and disposing of any diseased material immediately rather than leaving it under the tree or bush to reinfect the plant.

Kimbler said it was best to prune plants when they are younger; and if pruning an older tree or shrub, it was important to not remove more than a quarter of living material a year from an older, overgrown trees as to not overstress it.

“It took 30 years to get that way, it’s going to take four or five years to get it back (to the desired shape or size),” Kimbler said during the presentation.

It is also best to work on younger trees as they easier to shape, since any co-dominant branches or other potential problems have yet to grow too much and younger trees generally have smaller limbs and branches to deal with.

Larger branches also are not only harder to handle, according to Kimbler, but the plant’s subsequent wound is harder to heal.

Kimbler discussed the various types of pruning cuts — including reduction cuts, thinning cuts and heading cuts — as well as types of cuts to avoid. Kimbler said flush cuts — which cut a branch below its collar, or the swollen base of a branch — should be avoided as they make it harder for the limb to heal as calluses can’t form from all sides of the wound. Stump cuts, where too much branch is left attached, should be avoided as they also increase healing time.

“You shouldn’t be able to hang a baseball cap on your pruning cut,” Kimbler said after the event.

He also cautioned against using wound paint, except to prevent oak wilt when pruning oak trees during the growing season, as it also slows the natural callusing process.

After Kimbler’s presentation, there were a variety of questions from the roughly 20 people in attendance before the group went outside for a demonstration on one of the campus’ trees.

Several members of the group had an opportunity to participate in the pruning demonstration, putting to work the information they just learned.