tree question

Asked August 15, 2019, 6:33 PM EDT

, we have cut down and bull dozed 5 honey locust or black locust trees in order to build our home. Even before we did this, these trees always were throwing out new shoots. This behavior has only seemed to multiply with the trees gone. There are many, many large roots still left in the soil. How are we every going to stop these new shoots from popping up so we can plant a yard? We don't want to use chemicals, if possible. Will covering our planting areas with thick plastic stop them? Your help will be gratefully accepted! Thank you so much! Allene

Clackamas County Oregon

1 Response

Black locust trees are a real challenge to get rid of, because of their extensive suckering root systems. They are considered an invasive species in some parts of the country. Now that you have cut the main trunk down, it is trying desperately to survive by sending up all the sprouts it can from the remaining roots.You could certainly try covering them with plastic, but you would have to cover the entire area where the roots are, they are so strong that they would tend to lift or even penetrate the plastic, and it could take a year or even much more before the roots were truly dead. For all these reasons, in this case a careful, targeted application of an herbicide that is specifically labelled to kill tree stumps is really your best bet. Choose one that doesn't persist too long in the environment.

Cut the suckers to 3-4”, making a more vertical cut to expose more cut surface. You can also peel back some bark to expose the green cambium. Paint the herbicide on very carefully with a disposable foam brush, applying it primarily to the cambium. Don’t get it on any surrounding plants. This is best done in the fall when the tree is not in active growth – in the spring when the sap is rising, it can carry the herbicide up and out of the cut surface before it has a chance to work. You may need to repeat this treatment for complete control.

This article, “Cut Stump Application of Herbicides to Manage Woody Vegetation”, has more information you may find useful.

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