Would love some information on how best to permanently remove these plants.

also on the property: english ivy, invasive blackberry, english holly and some sort of very sticky little vine that covers everything like a net. Yikes!

Reporter
June 3, 2013, 4:04 a.m.

Hi, Jen. Thanks for your email. Knotweed's a tough one, but I don't normally recommend digging. I've talked to several homeowners who comment that digging seems to make more stems emerge. 'Yikes' is right. You also then have large knotweed rootballs which should go in the trash; it's not clear that the yard debris process deactivates knotweed roots or fresh stems, so that route of disposal could be spreading it to other unsuspecting homeowners.

If you wanted to continue cutting, I'd cut it EVERY time it got to about 2-3 feet tall. That will deplete the roots. Once it gets past that point, the leaves start recharging the roots, so this approach requires some vigilance. The stems, once they're completely dry, are fine for the yard debris bin.

If you wanted to try an herbicide application, we usually do that in the late summer and early fall, letting the plants grow up over the summer. If you wanted to go that route, shoot me an email at mitch.bixby@portlandoregon.gov, and we can talk about options.

In any event, if you have questions, feel free to reach me directly. Have a good week....

-Mitch

Mitch Bixby
June 13, 2013, 2:33 a.m.