What is the most effective way to get rid of knotweed? I'm planning to sheet mulch this winter with burlap, cardboard and wood chips. Will that get rid of it?

Reporter
Sept. 24, 2012, 8:56 a.m.

Hi, Bryan. Thanks for your email. I wouldn't expect to get very far with mulching, covering, or any kind of physical treatment. Some folks have dug theirs out; others have seen digging make things much worse. The substantial root reserves of this species seem to require a couple years of herbicide treatment. After that you might consider covering. Feel free to contact me directly (mitch.bixby@portlandoregon.gov) if you'd like to talk more about it.

-Mitch

Mitch Bixby
Oct. 3, 2012, 4:29 a.m.