The Importance of Pruning Trees– Even if Uncomfortable
Nyle Zikmund, Anoka County Master Gardener
Pruning your trees is arguably, as important as anything you can do to assuring a healthy tree. While unable to find data to support, planting your tree too deeply or shallowly is probably the most common mistake when planting trees. But failing to prune, especially young trees (from planting until 10 to 15 years depending on the species) can turn a fabulous tree into something less, or in worst case scenario, an absolute failure.
Pruning is easy, it really is.
1. Wait until the leaves all drop. (For oaks it is best to wait until extended cold temperatures).
2. There should only be one leader, if there is a second one starting; choose the best of the two and cut the other one off. This is the most critical prune – ONE leader only. Maples are notorious for this. Catching it early is the key.
3. If there are branches growing straight up off a branch, prune them off. If there are branches crossing another branch, prune them off!
That’s it! For the vast majority of trees, doing those three simple prunes; one leader, no vertical branches off a branch, and no branches crossing over another will do more to ensure a good healthy tree and by far, better than any tree with one or more of those three conditions.
With the leaves off it becomes very easy to see the branch structure and thus, easy to prune. If you get the tree started right, in those first five years; not only will the tree perform well, but your evidence of pruning will also diminish as the mature shape begins to form.
Always make the first cut an inch or two away from the final cut so the weight of the branch does not peel bark back or damage the tree and then make the final cut leaving a small shoulder to allow healing. Always prune at a 90-degree angle to the branch you are cutting.
There are a variety of tools you can use to prune your trees – all should be very sharp. I prefer a hand pruner for anything under three-quarter (3/4”) inch and a very sharp pruning saw, such as a Silky Zubat for everything else. Loppers (large pruners) and chains saws also work for larger branches but if you’re pruning correctly (early in the tree’s life cycle) you should not need those larger tools. For those wondering about treating the cut/wound with something, other than pruning oaks – there is no need to treat the cut. For oaks, I use green spray paint, applying three coats. This seals the wound, so it is less likely to attract the beetle that carries the deadly fungus.
In closing, along with planting to the correct depth, and pruning, the first five years are also critical to watering the tree. Plenty of guidance is available on the Internet from the University of Minnesota and/ or the DNR. New research has shown that those first five years are absolutely the most critical in the establishment of a root-ball that can withstand drought if needed and tolerate wet conditions as well.
Nyle Zikmund is an Anoka County Master Gardener and Certified Tree Care Advisor. He and his wife Theresa, also a Master Gardener; maintain 1.7 acres of forested/landscaped land in Blaine with 34 varieties of trees and a total of 204 trees.
