Northern Nevada gardening and landscaping: Prune for tree health, please
Submitted by Jeff Munson on Mon, 02/15/2021 - 10:38am
I spotted a poor pitiful ornamental crabapple tree recently. All its branches and top had been mercilessly sawed off leaving disfigured stumps. I hadn’t seen a so-called pruning job like this in a while. It was bad enough that the branches were ruined, but the entire main trunk of the tree was also whacked off.
Why do people do such drastic pruning? Some believe a tree is getting too tall and is unsafe. Some think this is how a tree should be pruned after seeing another tree pruned like that. Others may like the rapid growth of small branchlets that can result after a severe pruning giving a lollipop appearance. For several, it seems easier and quicker to cut everything out all at once, rather than to selectively prune only 25 percent of growth in a year, which requires more skill and care.
Trees shouldn’t be topped or pruned like this because it removes too much of the crown to adequately photosynthesize (produce food) for the roots, leaves and rest of the tree. The removal of the crown exposes the entire tree to damage from sunscald, a definite problem in Northern Nevada.
All the open wounds are portals for disease to infect, while also releasing chemical signals to insects saying “Come get me. I’m weak and susceptible.” And, long term, the wounds are unlikely to callus over, effectively leaving the tree vulnerable to disease and insect infestation for years (if it survives that long).
Although this radical pruning can encourage many new sprouts, they are weakly attached to the parent branch and become hazardous. Tree death can result from this kind of pruning. Besides the damage to tree health, this kind of mutilation is ugly!
Sometimes with fruit trees, primarily in commercial orchards, more severe pruning is acceptable to maximize fruit production. With this kind of pruning, trees may be replaced more often than they would be in a home landscape. Personally, I don’t want to look at a tree like this in my yard. It hurts my sense of what is good for a tree, and my sense of visual aesthetic.
To prune properly, stand back and evaluate the form of the tree. Remove branches that are crossing, rubbing, damaged, aiming toward the center of the tree, or dead. Prune to enhance not only the beauty of your tree, but its health. Oregon State University has an informative online resource here.
— JoAnne Skelly is an Associate Professor & Extension Educator Emerita at the University of Nevada Cooperative Extension. She can be reached at skellyj@unr.edu.
