Land Plants - invasive

Knotweed (Fallopia sp.) on Aug 1, 2008

Submitter does not have a specimen

Description of specimen

When the casino built a parking lot some time back they moved knotweed and scotch broom onto the vacant lot. The weeds have flourished there.


Dear Randall,

Thanks for reporting knotweed! I apologize for the very long delay in replying to your report. We have had a few bugs to work out since we launched the hotline and are working through them. I hope you keep on reporting!

You may already know that knotweed is a severe problem. This aggressive plant is taking over stream banks and degrading important riparian habitat. We definitely need to prevent its further spread! The Oregon Department of Agriculture and your local Cooperative Weed Management Area will be notified of your report so they can identify the land ownership, evaluate the urgency, and possibly control the population you reported.

Unfortunately, knotweed is already widespread in your area, so not all populations can be targeted for control. There are just not enough resources to control it all. There may be knotweed projects in your area, but they may be taking place upstream, as the only way to effectively control this plant is to work from the top of the watershed down.

Private land owners are responsible for controlling weeds on their property, but sometimes people don’t do anything because the task seems too daunting or they are unaware of the problem. The silver lining to this gloomy picture is citizen stewardship. There are many dedicated volunteers who join forces to uncover and protect their favorite areas from knotweed and other aggressive invaders. In some cases, the local Soil and Water Conservation District can help coordinate the effort and provide resources. If you are interested in joining a local volunteer effort to combat invasive species, or starting your own, there are some excellent websites listed above.

We hope you will keep on reporting! By looking for and reporting some of the less abundant, but equally as aggressive, invasive species, we can control them before they become tomorrow’s Scotch broom, English Ivy, or even knotweed. Check out this website for a list of plants and animals that are priority for early detection and control in Western Oregon:


Tania Siemens
OSU Sea Grant/The Nature Conservancy

Tania Siemens
Aug. 22, 2008, 11:55 a.m.