Dealing with the nuisance of tree suckers
Suckers. To a child this word brings visions of candy. To adults, one vision may be of nuisance stems growing from the base of trees.
Suckers are fast growing, vertical stems that originate from the root system. They are unsightly, but can also out-compete more structurally sound branches.
The best way to avoid suckers is to avoid planting trees known to produce many suckers. This is a good question to ask when selecting trees to plant.
Some trees naturally produce suckers. Canada red cherry, also known as Schubert chokecherry (Prunus virginiana ‘Schubert’) is famous for suckering.
Schubert chokecherry has been often sold as a small, ornamental tree. However, this so-called tree desperately wants to be a shrub; hence it repeatedly sends up suckers as most shrubs tend to do.
Other trees I receive suckering questions about are some crabapples and grafted maples like ‘Autumn Blaze’. And while quacking aspen is not often planted here because it is not well adapted to Nebraska, this tree is a good sucker producer.
Other trees develop suckers in response to an environmental or pest stress. For example, once an ash tree is infested by emerald ash borer (EAB), the stress caused can result in the tree producing basal suckers or sprouts on upper branches.
This is one of the symptoms we tell ash tree owners to watch for. But know that other stresses besides the borer also cause suckers to form. Further diagnostics is needed to confirm EAB if an ash tree is producing suckers.
Common stresses that lead to sucker growth is planting trees too deep and using rock mulch next to the trunk. Both practices result in long term stress for trees, shorten a trees life and sets trees up for being more susceptible to wind damage.
It is my experience the majority of trees are planted too deep. Before planting any tree, learn how not to plant too deep.
In a nutshell, the trunk taper - flare at the base of the trunk - should be visible above ground after planting, and the planting hole should be dug absolutely no deeper than needed for the trunk taper to remain above ground. Therefore, the trunk taper needs to be located before the hole is ever dug.
If you have a suckering tree in your landscape, removing these stems will be an annual job as there is no stopping suckers. While there are sucker stop products on the market, know that these products inhibit sucker production but will not stop it.
Once suckers begin to form, the best way to deal with them is to remove them promptly before they reach 6-12 inches tall. It is important to remove them at their point of origin on the trunk or root. If a small stub is left, it will sprout multiple suckers.
Be careful to avoid injuring the main trunk whenever cutting off suckers.
And know that replacing the tree with a better quality tree is an option to consider.
Kelly Feehan is a community environment educator for Nebraska Extension-Platte County.