Japanese Knotweed in Oregon/Washington

Asked January 23, 2019, 11:04 PM EST

Hello, Have you ever run into Japanese knotweed (Polygonum cuspidatum) while working in forestry or otherwise? If so, What was it like? Did you ever have to deal with removing or managing it and what were your tactics/methods? Is there anything special i should know about Japanese knotweed? Thanks!

Multnomah County Oregon

1 Response

Unfortunately Japanese knotweed is very difficult to manage in a wide range of sites. We have a number of good resources related to identification and management. Long term control with herbicides is usually the best option for management over time. Attempts at mechanical or physical removal often only spread this species making mangement more difficult.

Refer to the following publications and specific knotweed control in the PNW Weed Management Handbook: https://pnwhandbooks.org/weed/problem-weeds/knotweed-bohemian-polygonum-bohemicum-japanese-polygonum...