We purchased a home last winter that had been owned by an elderly woman that hadn't been able to take care of her yard. In the back yard there were tall woody stalks that looked a lot like Bamboo and were around 6FT tall. They took up about 300 SQ/Ft of the yard. In the spring I knocked all these dead woody stalks down, they were hollow and brittle. I pushed them down and ran over them with the lawnmower and they basically turned to saw dust. But once they started growing again... Oh my God... They grow anywhere from 6" to 1 foot in a day. I have sprayed them with every poison I could find short of atrizine. They wilted a bit but still grew back. What is this and how can I kill it? Max hight: 6Ft (or so) Area: Madison Wi Dark green single broad leaves Redish stems Root is a woody Rhizome like thing seems to spread via the roots. The neighbors said they have been fighting it for years, it grows right under the fence I've been told the tops grow small red barries later on in the year. They grow faster than any plant I've ever seen. Even after being cut down. Here is a picture taken right after they started growing. The sticks on the ground are the remains of the dead stuff I knocked down.
Never seen it in person myself but sounds like every description of Japanese Knotweed I've ever heard.
I agree looks like the nightmare Japanese Knotweed....time to call in the experts to get rid of it....could take a couple of years.
Yep, I googled it and found this: http://www.cabi-bioscience.org/html/japanese_knotweed_alliance.htm that's it. Holy cow, looks like I got the worst I could get huh? Any tips? I was planning on renting a roto-tiller next week and trying to dig up all the Rhizomes. Apparently I will need to burn them as well. LOL
Control of Knotweed (a stickied thread on top of the Pest Management and ID forum, since the question comes up so often) PS In the future, don't use "every poison you can find" - the first step in managing unwanted organisms is to identify them so you can then use a suitable control method, with poisons as a last resort.
I used a bunch of different kinds of poison. The only thing that had any effect was "Roundup, Poison Ivy & Tough Brush Killer Plus" Active ingredients: Glyphosate, isopropylamine salt 1% Triclopyr, triethylamine salt 0.1% It wilted, but did not kill the plants. I read that injecting the plants with a needle works a lot better... But it covers a huge area in my back yard. I'd need to inject hundreds of plants.
Crap, sounds like I need a hyperdermic needle. LAME Thanks for the help... I'll come back in 3 years and let you know if I've killed it... If it hasn't strangled me in my sleep by then.
You might want to look over the fence and see if your neighbor has the knotweed also, because if you get rid of yours, then theirs will come under the fence.
I was just reading the thread about vinegar and horsetail, was there research out there that someone may have tried vinegar on Knotweed? Just a curiosity question.
An update: I have Roto-tilled the entire area. My wife followed behind me, dug up the Riazomes and put them in Garbage bags.... Some were as large as 1 foot in diameter. We stored the bags in our garage... and guess what? The damned things started sprouting inside the bags!!! My entire backyard started sprouting the things again as well. They are slower growing now, so I deffinately hurt them. But there are still hundreds of them all over. I've been spraying all the plants with 2D4 about every 2 days for over a week and a half now and it's wilting the plants... but not killing them. This stuff is absolutely amazing. If they figure out how to get it to bear fruit it would solve the worlds hunger problems for sure.
It is edible, actually! You can eat the tender young spring shoots like spinach. It also (at all ages) makes very good browse for goats and cattle. Don't try either if it has been sprayed with weedkiller, of course.
hehe... well, I'm about a bad day and a six pack away from Salting the entire area. There should be a 3 day waiting period on 50lb bags of salt.
This plant is a big problem in parts of England. An international invasive weed conference in Ft Lauderdale several years ago had a delegation of knotweed killers.
