Removing Suckers

Several trees in our landscape are notorious for sprouting suckers when they have been cut off. These include Siberian elm, redbud, all varieties of maple trees, ash trees, locusts, and many more. The best way to control suckers on volunteer trees is to pull them when they are small rather than cutting them off. If you can’t pull them, or if you’re like me and find them when they are too big to snap off, there are some ways to prevent suckers from coming back to haunt you. (Note that when we say volunteer trees, we mean those that come from seed rather than suckers that originate from the roots of an existing tree. The recommendations in the remainder of this article are designed to kill these volunteer trees. Using herbicides on suckers will damage and very possibly kill the original tree.) Trees that commonly produce suckers include Tree of Heaven, honeylocust, black locust, hackberry, western soapberry, cottonwood, aspen, poplar, willow, and boxelder.

There are a couple of ways to control suckers coming up from cut-off trees; the first is to keep cutting them off at the ground level till they have used up their store of energy. Depending on the tree, this could be a couple of cuttings or a couple of years. The second way is to use chemicals. You can spray the sucker and then let it die before cutting it off, or you can treat the stump after you have cut the tree down. Triclopyr and glyphosate are the herbicides most commonly available to homeowners. Triclopyr is found in many brush killers, and glyphosate is found in Roundup and numerous other products. Read the label before purchasing to ensure a cut stump treatment is listed. Most often, the undiluted or lightly diluted product is applied to the stump immediately after cutting. A paintbrush is frequently used for the application, though some people dip their pruning shears in the products immediately before cutting them. Regardless, the stump must be treated immediately or within 5 minutes. Note that a paintbrush with foam rather than bristles is less likely to drip. Trees do not need to be actively growing to be controlled as long as applications are made when the temperature is above freezing.

Have questions? Contact our office where our Horticulture Extension Agent will assist you with questions.

Phone: (316) 321-9660

Email: callae@ksu.edu