Cottenwood tree suckers

Asked May 8, 2013, 9:11 PM EDT

How can I get rid of the small forest of cottenwood trees that have come up after a big tree was cut down? They are going to take over my property. Almost as obnoxious as the blackberries!! Please help. I don't want to spray with Roundup because they are next to some cedar trees I have carefully cultivated for several years. Is RTU Sucker stopper safe to use?

Multnomah County Oregon

1 Response

Good day, and thank you for using Ask an Expert.

As you have discovered, when a cottonwood is cut down, the roots re-sprout. All over the place! In order to stop the re-sprouts, you must starve the root system by removing all top growth as soon as you see it. Even though starving the roots will require several years, you can win if you are persistent. Use one of these techniques:
- Every week, break off all new sprouts
- Paint each new sprout with an herbicide (weed killer) which moves into the roots.
- Every week, cut off each new sprout, then immediately paint the cut surface of the stump with full-strength herbicide.

Although most people are familiar with Roundup products (active ingredient glyphosate) to kill weeds, the active ingredient triclopyr is more effective on woody plants. Triclopyr is in Blackberry & Brush Killer, Brush-b-gone, also Cut Vine and Stump Killer. Or use Crossbow which combines triclopyr with 2,4-D. All are available in general garden centers.

In the future, whenever you cut down a tree which has roots which are likely to sprout, immediately paint the cut surface of the stump with an herbicide containing the active ingredient triclopyr. Doing so will reduce the follow-up time needed to deal with root sprouts.

Remember this: The more persistent you are, the sooner you will win.