I have a huge patch of Japanese Knotweed around my yard. In the summer I don't mind it because it makes a nice windscreen, but it's spreading into areas where I don't want it. I'm setting out to kill off some of behind my shed it this summer by spraying it and putting it under dark plastic, then covering it with rocks. Hoping it works!
But for the rest, I don't want to try to tackle it that way. Too much work, and too much stuff to buy! I've got it in my head to try planting some equally obnoxious plants in among it and let them fight for space - maybe something like Creeping Jenny would be able to gradually choke it out?
Any thoughts?
Hi Kaaryn,
Welcome to The Helpful Gardener. Sorry to say that planting something to compete with the knotweed isn't going to work as it chokes out everything, especially native plants. Using another invasive non-native is also not a solution as you are just trading one problem plant for another. This plant is a huge problem in many areas and eliminating it completely is the only solution. It can be a long hard fight though. Your idea of cutting it down and covering with black plastic is a great way to deal with it. You need to be VERY careful that you don't spread it with bits that cling to tools and clothing. This pamphlet has some good control and elimination methods.
https://tncweeds.ucdavis.edu/products/outreach/knotweed-pnw.pdf
https://www.cabi-bioscience.org/html/japanese_knotweed_alliance.htm
Newt
Welcome to The Helpful Gardener. Sorry to say that planting something to compete with the knotweed isn't going to work as it chokes out everything, especially native plants. Using another invasive non-native is also not a solution as you are just trading one problem plant for another. This plant is a huge problem in many areas and eliminating it completely is the only solution. It can be a long hard fight though. Your idea of cutting it down and covering with black plastic is a great way to deal with it. You need to be VERY careful that you don't spread it with bits that cling to tools and clothing. This pamphlet has some good control and elimination methods.
https://tncweeds.ucdavis.edu/products/outreach/knotweed-pnw.pdf
https://www.cabi-bioscience.org/html/japanese_knotweed_alliance.htm
Newt
I'm considering maybe some kind of hardy roses that spread out well and would look nice hanging over a fence... in a couple more years I want to put picket fencing all the way around the yard.