Large leaf wetlands plant

Asked September 19, 2015, 1:11 PM EDT

This plant was found is a swampy low elevation valley near my location. I can't find a reference to it in my plant books.

King County Washington plant identification noxious weeds knotweed

1 Response

It looks like knotweed--an really nasty invasive, noxious weed. Yhere are several varieties in our area. It is recommended that you do NOT try to pull it out, because that just encourages growth. This is actually the best time of year to attempt eradication of Knotweed. This article gives more information. If you do choose to use an herbicide, be sure to FOLLOW ALL DIRECTIONS ON THE LABEL EXACTLY!.
https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/21809/em9031.pdf

In King county, control of Bohemian, Japanese, giant and Himalayan knotweed is required on the Green River and its tributaries upstream of the Auburn City Limits and on the Cedar River and its tributaries upstream of the Renton City Limits. If you have any questions about this, contact your local Noxious Weed Control Program, send an email, or call 206-477-WEED (206-477-9333)