One of the landscape tasks we can accomplish in the winter is control of volunteer and unwanted trees. Whether the annoying sprout came up during the summer or trees along the edge of the landscape that are creeping in, now is a good time for control measures.

The first step is determining whether you want to get rid of the tree in the first place. Some trees provide wildlife benefit or even landscape value – they just happen to be in the wrong place. If that is the case, consider transplanting in the spring rather than removal.

If removal is your desire, the next step is to determine the tree’s ‘source’. Trees that originate from seed would be considered volunteer and can be removed without concern. If the sprout originates from the roots of an existing tree, it’s called a sucker. They, too, can be removed, but if a herbicide is used to prevent re-sprouting, damage (or death) is likely to the original tree as well. According to KSU Horticulture Specialist Dr. Ward Upham, trees that commonly produce suckers include tree of heaven, honey locust, black locust, hackberry, western soapberry, cottonwood, aspen, poplar, willow and boxelder. Note as well that there is the potential for larger trees of the same species to be root-grafted. While not suckers, they do share materials between root systems, meaning that herbicide use on one tree could affect its neighbor as well. They too can be cut, but treating the cut stump area to prevent re-sprouting could damage the tree, which shares a root graft.

After we have determined that the tree is indeed a volunteer and not root grafted or a sucker (there are no like species in the neighborhood from whose roots it could originate or that might share a root graft), we can determine our control method. Small trees can be dug out. Any roots that are broke off could re-sprout, but thorough removal can be a good option. Larger trees will likely require cutting followed by treating the cut stump area with a herbicide. Eastern red cedar is an exception. It will not re-sprout if the tree is removed below the lowest green branch.

Most of our common ‘pest’ type trees - Siberian elm, hackberry, hedge, maple, etc… - do re-sprout and a chemical treatment is often necessary to keep your problem from growing back. Two common herbicides - triclopyr and glyphosate - are the herbicides most commonly available to homeowners. In most cases, homeowner formulations of these products call for application of the undiluted product to the stump area immediately after cutting. This can be done by using a paintbrush (a foam brush will drip less than a brush with bristles) or some other method to treat the cut stump area, and should be done within five minutes of making the cut for best results. Not all products are labelled for cut stump treatments, so be sure to check specific product labels to make sure they are labelled (and the label followed) for cut stump applications.

Trees do not need to be actively growing to be controlled. Treatment this time of year can be very successful as applications are made when the temperature is above freezing