Removing Suckers
There are several trees in our landscape that are notorious for sprouting suckers when they have been cut off. These include Siberian elm, red bud, all varieties of maple trees, ash trees, locust 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 pull 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 given 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 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. This could be a couple cuttings or a couple years depending on the tree. The second way is to use chemical. You can spray the sucker and then let it die prior to 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 as well as numerous other products. Read the label before purchasing to make sure that a cut stump treatment is listed. Most often the undiluted product or lightly diluted product is applied to the stump immediately after cutting. A paint brush is often used for the application though some people will dip their pruning shears in the products immediately before cutting. Regardless, it is important that the stump is treated immediately or at least within 5 minutes. Note that a paint brush 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.
