Land Plants - invasive

Japanese Knotweed (Fallopia japonica) on May 20, 2008

Submitter has sample

Description of specimen


My husband and I just moved into a "new" Old Farmhouse property in Eugene. We were lucky to have an electrician call to our attention what looked like beautiful flowering trees. He warned us about the insidious nature of the Japanese Knotweed, which he identified. My son and I cut it all down, where I noticed it was very much like bamboo. I did some reading on it, and realized it was going to be tough to eradicate, but I wasn't prepared for the resurrection that occurred this spring. I know it all has to be dug out, every tiny piece of it, but it is all over the property next door, which is owned by someone out of state, and has no house on it. We are very near a creek, that I think feeds into the Willamette river. I read that 1/8" piece of root can start a whole grove of this stuff, so I am concerned. I don't even know if I can get it out of my yard, let alone the property next door. Can you give me any help with information on how to eradicate this plant. Cardboard and black plastic do not seem to curtail its reappearance. I don't use any chemical herbicides.

Thank you for your help,

Nadya and Don Carson

PS. We have included a picture attached to this eMail.



You are correct in your ID it is indeed Japanese knotweed. As far as control of this noxious weed, you are already aware that this a difficult plant to control. You mentioned that you do not like to use herbicides, but if you hope to get the upper hand on knotweed that is going to be your best option. Manual and mechanical options are not effective. If you want a herbicide recommendation you can contact Glenn Miller, ODA in Eugene. His phone number is: 541 683-6180.

Thank you for your submission: Tim Butler, ODA Noxious Weed Control Program

Tim Butler
May 28, 2008, 6:39 a.m.