Japanese Knotweed

[welshfox]

I moved into a property last year and this summer found that I also own a 60-80ft piece of land at the rear of the garden, but this is absolutely crammed with japanese knotweed and it is spreading like wildifre into my garden. I want to get rid of it all but dont know where to start. I cut it all down and went away for a fortnight - when I returned it was all back again - talk about gutted!

I'd like to know if anyone knows of any weedkiller or something that will kill it off for good? My dad wants to set fire to it but I'm afraid incase theres any wild animals living in there at the moment. Any suggestions please?
Thanks for reading

[jake-the-peg]

This stuff is an absolute nightmare - more than you can imagine and you really need to know what you're doing.

Check out the government page here:

http://www.netregs.gov.uk/netregs/processes/36 7836/?lang=_e

Note that they say disposal of it probably needs handling as 'controlled waste'

It recommends multiple sprayings with glyphosate (round up for example ) during the growing season but that even then that might not be enough.

I would imagine that setting fire to it would encourage it to grow back stronger.

Note to it says never use a strimmer, chipper or mower on Japanese knotweed

You might also want to look here:
http://www.cabi-bioscience.org/html/japanese_k notweed_alliance.htm#control

[Thunderbird+]

Hi welshfox, As you've obviously found out already, it's an extreamly dificult weed to eradicate! It is resistant to most weedkillers but herbicides that contain the chemical 'Glyphosate' seems to be the most effective, although the underground creeping stems (Rhizomes) can take about 3 years to die after repeated applications.
I think the best approach is to keep cutting it down to ground level then spraying the fresh re-growth and try to exhaust the plant that way, then when you think you've got it beat dig out (ALL) the rhizomes and root fragments and burn them on site.
If it go's into a landfill site, your local authority needs to be notified, as it needs to be buried at least 5 m deep.
You should be able to get some good advice re control, disposal etc from the Environment agency, as I believe it is a notifiable weed subject to strict procedures. Good Luck Tbird+

[Thunderbird+]

Ps, I did'nt see Jake's post when I started mine but it looks like we're coming from the same place. :-)

[welshfox]

Thanks for those - this really is the bain of my life. I found recently that the roots from it have gone under my garden wall and are now growing strong and healthily 10 feet away from where the plants are, into my flower beds. I would like to get a digger in to dig it all out, but had already done a lot to my garden prior to finding out I owned that land, so am reluctant to lose all that progress I had made.
Even my next door neighbour is complaining now that I havent done anything about it - needless to say I told him to complain to the people who lived there before me as they did nothing about it either and they were there first!!!

Thanks for all your help - I've got the lovely job of trying to cut it all down now and find somewhere that will take it - God I HATE JAPANESE KNOTWEED!!!!!!

[chicklin]

Apparently its the first plant to recolonise (sp?) an area after a volcanic eruption, so it's incredibly resilient. Its a massive problem all over the country. Good Luck - sounds like you'll need it!

[suzy64]

don't know if this site is any help :o)
http://www.japaneseknotweed.co.uk/

[welshfox]

thanks for that - don't think there's going to be an inexpensive solution to this but hey ho. Can't believe if I do nothing about it I'm breaking the law though!! I wonder if I could sue the people who lived there before me for hte cost of removal? hmmmmm - always a thought ;-)

[stukey]

Hi, I discovered some in a clients garden a few years ago, thankfully there were only a dozen or so stalks, dont know where it came from it certainly wasnt there the year before, however I poured neat round up down each stalk (if you cut them down by half they are hollow) this got rid of most of them, did the same the following year and there was none this year allthough i will keep a close eye on the area next year. good luck

[welshfox]

I'll definately try that. I was contemplating pouring hot wax in the hollows of the stalks, but knowing how much of a nightmare this stuff is, I dont think it'd be worth the effort. Thanks for that though - will definately try it. Now just have to find a cure for my leaking ceiling.........

[Hcaterpillar]

Burning it might be good for clearing an area but it won't kill it. It is possibly the most heat tolerant plant there is. It will just shoot up again from the base.
I've seen a cheap method where you cut back the knotweed, (then burn the stems) then using large tarpaulins or old carpet, cover the area blocking out the light so it is unable to photosynthesise. You need to keep returning back every week or two weeks to tread on the tarp to break off the stems trying to push through the tarp.
This site is some help
http://www.gardening-...panese-knotweed-costs