Contractor Talk - Professional Construction and Remodeling Forum banner
1 - 18 of 18 Posts

·
This space for lease
Joined
·
5,323 Posts
Discussion Starter · #1 ·
Anyone know how to kill this stuff? It's like out of a science fiction movie. It keeps coming up, it's a foot tall from last weekend of weedwhacking to ground level. I've used bleach. I've used drain cleaner. It just laughs it off.

I've researched it but apart from digging up the entire area or moving I don't see a spray solution that works.
 

·
Radical Basement Dweller
Joined
·
29,469 Posts
I'm a fan of Ground Clear...used concentrated, straight from the jug.
If you weed whack it and then spray it immediately, the chemical can get into the open "wounds".
 

·
Designer/Contractor
Joined
·
5,323 Posts
Never heard of it so I did some looking on the net and there's a lot of information regarding it, most of the information advocated cutting down to about 2" high after August and then applying glyphosate (roundup).

Also found this regarding the plant which is interesting:
japanese knotweed contains resveratrol. Discover how resveratrol extracted from knotweed compares to resveratrol from grapes and how it can improve your health.
 

·
This space for lease
Joined
·
5,323 Posts
Discussion Starter · #4 ·
Thanks, I'll try the ground clear first, the state (DNR) recommends the Roundup but they lean towards the eco friendly solution and people have had limited success with it. This is a hearty plant, it busted three pressure treated 4x4 fence posts off at the concrete. It grows into a "knot" like root like a hardwood. In England its tearing up railroad rails. I let this stuff go on too long, thinking it was bamboo, and it got well established and was claiming too much yard. The fence was the last straw, it's war now. WMDs, whatever it takes.
 

·
Gebhardt & Co Painting
Joined
·
126 Posts
Thanks, I'll try the ground clear first, the state (DNR) recommends the Roundup but they lean towards the eco friendly solution and people have had limited success with it. This is a hearty plant, it busted three pressure treated 4x4 fence posts off at the concrete. It grows into a "knot" like root like a hardwood. In England its tearing up railroad rails. I let this stuff go on too long, thinking it was bamboo, and it got well established and was claiming too much yard. The fence was the last straw, it's war now. WMDs, whatever it takes.
Try using straight white vinegar. Works wonders. Yes I am serious!
 

·
Registered
Joined
·
2,050 Posts
That stuff is spreading like wildfire here in southwest pa. The problem with it, is that it has a rhizome instead of roots, so whatever giant patch you have, is probably just one giant plant.

My friends are some of the few people I know who have had some success fighting it. The vinegar, salt, soap thing seems to work pretty well, as does the round up. I think they may have been also laying down black plastic in the early spring before the shoots started to come up.

I worked on a big project last year, the customer had an addition out on during the winter, and come spring, he had knotweed shoots sprouting between the new and old parts of his house in his mudroom. It popped out behind the baseboard! It's a pretty tenacious plant, but with consistent methods, it can be beaten. Good luck!
 

·
Registered
Joined
·
8,240 Posts
I bet a herbicide named Remedy would do it. I think it is mfg. by dow and works well in my battle with different types of cactus. Not cheap, about $100.00 a gallon
 

·
This space for lease
Joined
·
5,323 Posts
Discussion Starter · #11 ·
The stuff did spread around and was here before I moved in. The neighbors have it and aren't managing it. The rhizomes really reach to, some of it pop up 5 to 6 feet away. Pulling it up encouraged it to spread out and fast! I have vinegar and will try it first then move up to weapons grade materials as needed.
 

·
This space for lease
Joined
·
5,323 Posts
Discussion Starter · #13 ·
So this stuff is on the east coast as well? Whoever brought it here should have been shot, what were they thinking? The fact that it looks so much like bamboo is why I let it go for so long and I'm probably not the only one.
 

·
Registered
Joined
·
2,050 Posts
So this stuff is on the east coast as well? Whoever brought it here should have been shot, what were they thinking? The fact that it looks so much like bamboo is why I let it go for so long and I'm probably not the only one.
it comes over from shipping containers and gets spread along railroad tracks as they are shipped across the country. Same with stink bugs.
 

·
Registered
Joined
·
11 Posts
I previously used a glyphosate-based product when tackling Jap knotweed. It does the job but you will likely see re-growth a few times. In which case, just continue to apply as and when. Good luck!
 

·
Joe The Handyman
Joined
·
68 Posts
My own backyard was covered in it years ago.
I finally got it under control with poison ivy/poison oak foam that you spray on the leaves. I think it was ortho and I'm not sure you can still get the foam spray , but i would try some formula that works on poison ivy.
Whatever you do, don't cut it below ground, it just created more shoots

They call it "mile a minute" around here. I swear you can hear it grow
 

·
This space for lease
Joined
·
5,323 Posts
Discussion Starter · #18 ·
My own backyard was covered in it years ago.
I finally got it under control with poison ivy/poison oak foam that you spray on the leaves. I think it was ortho and I'm not sure you can still get the foam spray , but i would try some formula that works on poison ivy.
Whatever you do, don't cut it below ground, it just created more shoots

They call it "mile a minute" around here. I swear you can hear it grow
Too late. I dug up the roots, some of them were 10 lb. lumps of hardwood. I did get it beat back with the HD Roundup substitute but we'll see what happens in spring. I don't know about hearing it but you can watch it grow.
 
1 - 18 of 18 Posts
Top