Land Plants - invasive

Japanese Knotweed (Fallopia japonica) on May 28, 2008

Submitter does not have a specimen

Description of specimen

I can easily provide one. I am having difficulty keeping this stuff from spreading into my backyard.


Dear Richard,

Thanks for reporting knotweed. Yes, 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!

Unfortunately, it is already widespread in your area, so not all populations are targeted for control; there are just not enough resources to control it all. Land managers are taking a strategic approach and controlling knotweed where it is clearing threatening an important resource – like a natural are or a structure.

It is still important to keep it out of your yard to prevent its further spread. Not to mention it will destroy your yard, as well! I would suggest contacting your local Soil and Water Conservation District ( or for additional information about knotweed control in your area. They may also be able to help you approach your neighbor about controlling their population. Many people, once they realize the negative effect of knotweed and how it actually decreased the value of their land, will be motivated to control it. Good luck!

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
June 7, 2008, 7:20 a.m.