Japanese knotweed - How to Kill

Asked August 5, 2016, 6:57 PM EDT

Hello, I've got an infestation of what I believe is Japanese knotweed that I can't seem to get a handle on. In fact, they're so vigorous they've created a privacy fence around my yard and have started taking over the neighbor's yard! I took a picture of a small bunch next to my garage that I cut down just two weeks ago. They're already nearly two feet high! Please, save me and my neighbor from these awful plants. How do I get rid of them? I've tried cutting them down and spraying them with roundup, but it just makes them wilt a little and then they come right back. I've been battling them for a couple years, and I'm just not sure what to do.

Ramsey County Minnesota

1 Response

Japanese knotweed is a nasty plant. Don't expect a quick easy solution, but you can rid yourself of it with persistence. Roundup works best in fall. It will multiple applications per year and may take years to kill. You should share this info with your neighbor, otherwise it will simply return from your neighbor's property.

http://www.extension.umn.edu/garden/yard-garden/weeds/mexican-bamboo/

https://www.youtube.com/watch?v=UnxVZRgN_qU&index=3&list=PL942C7AED5F1D72A7