Japanese Knotweed

21 years ago

I have a large patch, 400sf or more probably that I have started work on. So far I have piled all the stems for burning this weekend, raked up all the old stems and leaves and added those to the pile for burning, dug up the biggest root clumps and added those to the pile, and am about 35% done turning the soil with a shovel to remove all signs of the roots in the top 6 to 8 inches. I know that there are all sorts of horror stories about this stuff but tell me what you think of the rest of my plan.

Im going to finish turning the soil and remove as much root as I can. Then I want to plant an apple tree, and grass. I am told to expect the plants to sprout up anyway, and I was just going to keep mowing them down with the grass, but from reading I think what Im now planing on doing is getting a turkey injector syringe, letting the plants grow a couple feet high, and injecting 50% glyphosfate(or whatever it is) Roundup into the hollow in the plants, give it a week to do its job and then cut them down, and repeat this process every time they grow up again untill the plant is dead and gone.

Am I going about this all wrong? would it be ok to just keep mowing this thing? what do you guys think of this plan.

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Comments (4)

youreit
21 years ago
Here's what my weed book says about eradication -

"...it's difficult to kill with herbicides, so evict with a sturdy shovel. Dig deep to remove the spreading rhizomes. Continue the operation until you are sure the soil is free of any leftover pieces of root. Lay the roots on a patio or other solidly paved area to wither and die in the sun. Then dispose of them in the trash. Only stems that have not yet gone to seed can be composted."

I hope you get rid of it, frank! It's terribly invasive in many places. :(

Brenda
mabeldingeldine_gw
21 years ago
Frank,

I was successful in killing off quite a bit of it with a similar method. I have more to do this summer, that stuff it evil!

Mabel in Maine
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nejalina
20 years ago
I have 2 huge patches I have recently begun work on...we just bought our house last fall...and had no idea what we were getting ourselves into with the "cool looking bamboo" in the yard. Well...since then I have learned a LOT quickly! But it seems the bottom line is eveyone has varied opinions and there is a lot of experimenting going on.

After reading your plan my thoughts are - that it sounds great but I would leave a few weeks time for the poison to take effect - I noticed it took several weeks for it to show any signs of damamge...(i also use glyphosate 50%) but ALSO - it is best to treat it with glyphosate in August or September when the plant is bulding it's reserves for the winter - it is taking nutrients down to it's roots...so it will take the poisen down into its roots most succesfully at that time...and its the roots you need to kill to eradicate it.

I did one treatment in early spring - and it still came back but alot shorter and definately damaged...so I plan to do one more treatment in aug/sept.

GOOD LUCK!!!
dian2
20 years ago
Good luck indeed. I have been spraying with above, injecting into stems and mowing for 2 years now. Bah humbug. i would like to kill whomever imported this stuff. I am now in the process of trying to dig out the roots. You are lucky yours are 6-8 inches only. I have gone down as far as 2 shovel lengths to dig some up. Hopefully if they regrow it will be seen early enough where the roots are not spread out in 10 foot lengths..
wonder if it would be easier to roto till and then shovel through to pick out the roots?