New Way to Treat Japanese Knotweed

[dapjwy]

https://vtinvasives.org/news-events/...treat-knotweed

The theory is that the knotweed stems will emerge from buds on the underground rhizome in early spring and will grow through the steel mesh. As the stems continue to grow, they will expand in diameter. At a certain point, the stems will push against the steel mesh and girdle themselves. The surface growth (stems and leaves) of the plant wilts and will eventually die, but the rhizome will continue to push new stems up through the ground (and wire mesh). This will continually kill the stems and will lead to the depletion of rhizome carbohydrate stores, which are required by the stems for growth. This cycle will repeat until the end of the growing season, when the plant enters a period of dormancy. Normally, the knotweed will have a plentiful store of carbohydrates stored in its rhizome to begin growing again in the spring. However, after a season of trying to outsmart the steel mesh on top of it, the knotweed will not have any energy stored up to continue growing in the next season.

[NEWisc]

What an interesting idea!! Easy to do, more or less 'one time application', environmentally friendly method.

It also gets the imagination thinking about dealing with other difficult to control invasive plants using this concept. Maybe 1/4" or 1/8" hardware cloth for phragmites, 1/8" cloth for non-native thistles??

1/8" hardware cloth is sometimes hard to find, but is is available.
https://www.homedepot.com/p/Fencer-Wire-1-8-in-x-2-ft-x-100-ft-27-Gauge-Hardware-Cloth-CA27-2X100MF18/306743905

Nice find Dap!

[jack]

Originally Posted by dapjwy

https://vtinvasives.org/news-events/...treat-knotweed

Are you going to try it on that knotweed you have??

[dapjwy]

Originally Posted by NEWisc

What an interesting idea!! Easy to do, more or less 'one time application', environmentally friendly method.

It also gets the imagination thinking about dealing with other difficult to control invasive plants using this concept. Maybe 1/4" or 1/8" hardware cloth for phragmites, 1/8" cloth for non-native thistles??

1/8" hardware cloth is sometimes hard to find, but is is available.
https://www.homedepot.com/p/Fencer-Wire-1-8-in-x-2-ft-x-100-ft-27-Gauge-Hardware-Cloth-CA27-2X100MF18/306743905

Nice find Dap!

Thanks. I saw it shared on a Facebook group....and knew I had to post it here.

I like how you are extrapolating its use on other invasives. I might have to try your idea out on our mugwort problem!

[dapjwy]

Originally Posted by jack

Are you going to try it on that knotweed you have??

I have thought about it, but I would think mowing would prevent it from photosynthesizing--and work faster than girdling. Still, it would require less work--energy I could expend on other projects or maintenance. Something to think about.

[Martha]

Originally Posted by dapjwy

I have thought about it, but I would think mowing would prevent it from photosynthesizing--and work faster than girdling. Still, it would require less work--energy I could expend on other projects or maintenance. Something to think about.

I've heard that you should let it grow about a foot and then mow it. That way it sends its energy stores to produce the new growth and then doesn't get the chance to renew its energy. Keep doing the grow and cut helps weaken it.

I think the same method may be true for mugwort. I have loads of that bastard. It pulls out all innocently, but then you realize there's a 1/2" diameter root system that crisscrosses your entire yard. Gah.

[Martha]

I can just envision seeing the metal hardware cloth being pushed up in the air because of the force of the knotweed growing.

[NEWisc]

Good point - some tent/garden stakes or heavy objects would have to be included in the plan.

Another consideration is that it probably would not work for woody plants, since many of them have the ability to heal around a bark injury. The bark injury from the wire mesh would most likely only affect part of the stem at any given time.

[skip1909]

I saw some knotweed growing in an empty lot today, except it was covering about 1/4 acre. That would be a lot of hardware cloth.

[Rebek56]

Interesting idea. I started out the spring whacking knotweed along the portion of our town's river trail near the house, having read that cutting it to the ground every two weeks is likely to kill it in a couple of years. Unfortunately, I lost track of time and went back a week late--and the new knotweed is nearly as tall as I am!