Though trees are a vital part of our landscapes, there are situations where
volunteer trees need to be controlled. This is often a case of the wrong
plant in the wrong place. If the tree is a desirable species, you may want
to consider transplanting in the spring. If it is not, active control
measures would be in order.
Most trees resprout after cutting though some don’t. Cutting those that
don’t resprout is an effective control method. For example, eastern redcedar
is a very common species that will not resprout after cutting.
Those that do resprout include Siberian elm, hackberry, osage orange
(hedgeball), oak, ash, aspen, cottonwood, maple, sycamore, willow and many
more. These trees will either need to be dug out or the cut stump treated
with herbicide after cutting.
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. It is also possible for
larger trees of the same species to be root-grafted.
Even though root-grafted trees are not suckers, they do share materials
between the individual root systems and therefore herbicides used to treat
one tree can be passed to its neighbor.
Let’s say we have a tree we want to control that is a volunteer and there
are no other trees of the same species close enough to be root-grafted that
we do not wish to harm. What do we do? If the tree is any size, you probably
do not want to dig it out. That leaves using a herbicide on the cut stump.
Basal treatments are also possible but that is beyond the scope of this
article. First decide what herbicide to use.
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 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. Actually this
time of year is a very good time to treat as long as applications are made
when the temperature is above freezing.

By: Ward Upham