Pruning Trees and Other Perennials

Jesse Fulbright, MSU Liberty County Extension

I looked out our large picture window to the south the other day and realized it is that time of year again.  It is time to start outside yard work, specifically, pruning and getting trees and perennials in shape for the coming season.  Many of us know we need to prune but we don’t know why. 

According to the Montana Master Gardener Handbook, pruning can make a barren tree fruitful, bring overgrown plants back into bounds and can make a flowering plant bloom more profusely.  However, the catch is, it needs to be done properly.  Pruning is the removal of plant parts with a specific purpose in mind of changing the direction and amount of new plant growth, ultimately affecting the shape the plant.

For trees, pruning can best be explained by looking at what needs to be taken off first.  Look for signs such as water sprouts, those tiny branches coming out of the trunk or branches straight out.  Look for suckers near the base of the tree, crossed branches that will rub and injure the tree, dead branches, stubs of branches that weren’t properly trimmed before, and double leaders.  Double leaders are those branches that come to a fork and are more or less equally growing and forming two main stems.  You only want one main leader.  You never want to prune any more than about 1/4 to 1/3 of the tree’s canopy in one year, otherwise you take away its ability to capture nutrients.  Topping, hatracking, rounding or any other practice that decimates a tree, leaving it denuded is never an accepted tree pruning practice.  If your tree is like this, its life has been severely shortened and you might as well take the tree out for the bad that has occurred.

When thinking of pruning perennial shrubs or other plants in your yard and garden, you prune to promote plant health.  Eliminate dead, dying or diseased wood now before new growth occurs.  This is two-fold in purpose.  First, it is much easier to eliminate old tissue when you don’t have to trim around new tissue.  Secondly, if you have old, dead or diseased tissue, you want plant nutrients going to new tissue for vibrant and productive growth as well as disease suppression.  Pruning a thicker plant, such as a hedge also allows light to penetrate through the plant. 

If you have any questions about pruning, or feel hesitant about what to prune I would encourage you to contact your local county Extension office.