Japanese Knot Weed- anyone dealt with it
James - 10/6/13 at 05:22 PM
So, last Saturday spotted a house for sale that my girlfriend and I really, really like.
Loads bigger than ours, another 'do-er up-er' project, lots of potential, and most importantly... a garage! 
3 days later our house is on the market and 5 days later we've had some good offers on it! 
Had another look around the potential new place on Sunday with brother-in-law who's a gardener (though reason we took him is he's an
experienced property investor).
House looks great, blah blah, pity he's says, about the 10'x6' patch of Japanese Knot Weed at the bottom of the garden!
Garden is about 100' long so its a way away from the house/foundations but having Googled it a bit I'm fairly terrified- and also
disappointed we potentially can't buy the house of our dreams. (Reports of mortgage companies not touching you, difficulties buying insurance
etc. etc.)
I know it can be treated with poison, or alternatively dug out (5' or 6' deep digging, soil is considered hazardous waste etc. etc.!
).
Has anyone dealt with it before? Successfully or otherwise? What did you do? What did it cost?
All help greatfully received- knew this house was too good to be true! 
James
scudderfish - 10/6/13 at 05:47 PM
Yikes! From http://www.environment-agency.gov.uk/homeandleisure/wildlife/130079.aspx
It spreads through its crown, rhizome (underground stem) and stem segments, rather than its seeds. The weed can grow a metre in a month and can cause
heave below concrete and tarmac, coming up through the resulting cracks and damaging buildings and roads. Studies have shown that a 1cm section of
rhizome can produce a new plant in 10 days. Rhizome segments can remain dormant in soil for twenty years before producing new plants.
Nasty stuff.
coyoteboy - 10/6/13 at 05:52 PM
Family member has a similar knotweed infestation. He chopped it down, double bagged it and took it to be incinerated and has spent the last 4 years
injecting poison into the stems each year. They're still not dead. I think the horror stories are due to it being near property or rivers as
they're the two places you don't want it, but it's not illegal to actually grow it AFAIK, just illegal to cause it to spread (which
happens when it's disposed of badly, chopped down carelessly or let fall into water courses).
Check out:
http://www.cornwall.gov.uk/default.aspx?page=19756
The local council just repeatedly spray the sites and leave them to die off, then they spread a bit more and they do it again.
For correct treatment the soil needs digging down to about 3m and incinerating IIRC.
[Edited on 10/6/13 by coyoteboy]
coozer - 10/6/13 at 05:54 PM
Yep, its nasty stuff.. I would try a strong mix of sodium chloride on it, that might see it off!
coyoteboy - 10/6/13 at 05:55 PM
quote:
Originally posted by coozer
Yep, its nasty stuff.. I would try a strong mix of sodium chloride on it, that might see it off!
Not much chance I'm afraid, you kill off the visible stuff and it keeps on going. You need to literally inject it on an annual basis even when it
looks dead.
Doctor Derek Doctors - 10/6/13 at 06:04 PM
Sounds like an excuse to hire/buy a digger!
mazie - 10/6/13 at 06:06 PM
Not a personal experience but one of a friend, he had to dig an area out 3 metres deep and 6 metres across, and unfortunately no guarantee its not
coming back. He didn't do the work himself but had a company in who were suppose to be experts at the removal.
perksy - 10/6/13 at 07:27 PM
Is the house really worth all the future hassle and potential pit-falls ?
(including possible issues with the neighbours)
If you fancy a challenge then great, but personally i'd walk away, There'll be other houses...
coyoteboy - 10/6/13 at 07:35 PM
It's a great reason to ask for a massive price reduction. Get some quotes on proper removal.
Peteff - 10/6/13 at 07:40 PM
quote:
Originally posted by coozer
Yep, its nasty stuff.. I would try a strong mix of sodium chloride on it, that might see it off!
Salt ? The recommended treatment is Glyphosate but it's not cheap stuff. Cut the individual stems and inject it down them at the end of the
growing season and it may take two or three years to finish it off completely.
britishtrident - 10/6/13 at 08:09 PM
You will probably have to keep spraying for 10 years, and even then have keep an eye open for new growth.
dave r - 11/6/13 at 07:47 AM
we have it one one of our sites at work
walk away, and look for somehing nicer......
has cost our company a lot of money, and its still there
TimC - 11/6/13 at 09:04 AM
Its horrible stuff but there is quite a lot of hysteria around it.
Mrs C has done a lot of research on the matter - I'll chat with her tonight and tell you what she has found.
MP3C - 11/6/13 at 09:43 AM
Ahh an interesting post!
Well I am a Building surveyor but I must say that a lot of surveyors won't be able to recognise the stuff anyway. It is just a very invasive
plant which is impossible to contain. In the past everybody was planting it in their gardens as it was quite an intresting plant. However as it
can't be contained it becomes a problem. Typically not a major problem for house foundations (only in a select few cases) if it is 7m away from
your building you shouldn't have a problem getting a mortgage if you show that you are trying to kill it. Typical method is poison the plant over
period of 3 years (usually takes 4 just to make sure) or dig it up and bury the material 5m deep or if not make sure that you cover the hazardous soil
with a root barrier membrane - only problem with this is that the roots can extend upto 7m away from the plant it's self and 3m deep so you will
need a pretty big hole to bury the stuff. Also getting rid of it costs usually about £50 a tonne (excluding landfill tax) so gets expensive.
Take a look on the RICS website. There is a good home buyers guide to Japanese Knotweed.
Link
If in doubt say to the seller that there is Japanese Knotweed on the property and get the cost of the property reduced by the amount it will cost to
get it eradicated - costing you nothing but gaining a few gray hairs in the process.
Hope this helps
Matt
[Edited on 11/6/13 by MP3C]
Peteff - 11/6/13 at 10:23 AM
quote:
Originally posted by MP3CTake a look on the RICS website. There is a good home buyers guide to Japanese Knotweed.
Link
If in doubt say to the seller that there is Japanese Knotweed on the property and get the cost of the property reduced by the amount it will cost to
get it eradicated - costing you nothing but gaining a few gray hairs in the process.
Hope this helps
Matt
[Edited on 11/6/13 by MP3C]
It's also not notifiable but you can't transport it without a waste carriers license or similar but there's nothing to stop you digging
it up and burning it on site, it dries out pretty quickly. If it spreads to other people's property you can be sued for it's removal cost,
there's a field full of it just over the wall from our garden and it gets nearer every year.
MP3C - 11/6/13 at 10:33 AM
quote:
It's also not notifiable but you can't transport it without a waste carriers license or similar but there's nothing to stop you
digging it up and burning it on site, it dries out pretty quickly. If it spreads to other people's property you can be sued for it's removal
cost, there's a field full of it just over the wall from our garden and it gets nearer every year.
You don't need a waste carriers license if you are the owner of the property of where the waste is coming from. So if you did the work yourself
you could transport it to your civic amenity site without charge.
Your dilemma reminds me of the houses that are getting destroyed by coastal erosion in Norfolk with the Knotweed getting closer and closer each year
:S
You could take a civic nuisance claim out against the owner of the contaminated field however this will more than likely just make you unpopular,
easier solution to stop it getting into your garden is install a vertical root barrier. However it is then costing you for somebody else's
problem... Damn Knotweed!
Matt
[Edited on 11/6/13 by MP3C]
[Edited on 11/6/13 by MP3C]
coyoteboy - 11/6/13 at 12:46 PM
quote:
but there's nothing to stop you digging it up and burning it on site, it dries out pretty quickly. If it spreads to other people's property
you can be sued for it's removal cost,
Burning it on site isn't really an option as you can't burn it in a normal incinerator, it has to be filtered output as the rhizomes can be
spread by unfiltered burning (i.e. like/with ash lifted as the fire burns). This is considered causing it to spread (according to my old local council
control team).
James - 12/6/13 at 04:27 PM
Well, looks like we're going to give it a go (buy the house that is).
Most people seem to think that the plant is treatable so I'll keep you updated over the next few years!
Now planning what to do with the garage- far more important than the rest of the house! 
Thank you for all the advice!
Cheers,
James
[Edited on 12/6/13 by James]
jacko - 12/6/13 at 06:29 PM
And DON'T plant bamboo that takes a lot of getting up
don't ask how i know 
Jacko
Benzine - 12/6/13 at 06:35 PM
You can make wine and beer out of japanese knotweed
DarrenW - 13/6/13 at 06:18 AM
quote:
Originally posted by jacko
And DON'T plant bamboo that takes a lot of getting up
don't ask how i know
Jacko
The trick with Bamboo to stop it being invasive is to dig a big hole, put in a big plastic pot then plant the bamboo in it. Of course it is still
possible for one or two of the stems to burst the pot if it isnt strong enough.
iank - 13/6/13 at 07:18 AM
quote:
Originally posted by DarrenW
quote:
Originally posted by jacko
And DON'T plant bamboo that takes a lot of getting up
don't ask how i know
Jacko
The trick with Bamboo to stop it being invasive is to dig a big hole, put in a big plastic pot then plant the bamboo in it. Of course it is still
possible for one or two of the stems to burst the pot if it isnt strong enough.
Picking the species of bamboo is also key, some are quite restrained and only spread slowly - others are insane and cause big problems.
iank - 13/6/13 at 07:18 AM
quote:
Originally posted by James
Well, looks like we're going to give it a go (buy the house that is).
Most people seem to think that the plant is treatable so I'll keep you updated over the next few years!
Now planning what to do with the garage- far more important than the rest of the house!
Thank you for all the advice!
Cheers,
James
[Edited on 12/6/13 by James]
Good luck
MikeRJ - 13/6/13 at 07:40 AM
quote:
Originally posted by jacko
And DON'T plant bamboo that takes a lot of getting up
don't ask how i know
Jacko
Damn right, my wife planted a load of it about 8 years ago and it's an utter PITA. There are different varieties though and some are much less
invasive than others.
She goes mad when I start hacking it back as apparently any shoots you cut will die, a fact which makes my hacking even more enthusiastic
Peteff - 13/6/13 at 08:48 AM
quote:
Originally posted by Benzine
You can make wine and beer out of japanese knotweed
The new shoots taste like rhubarb apparently, Alice Fowler did a recipe for it.