Japanese Knotweed

Dave Spence

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Does anyone have any experience of Japanese knotweed, I have seen a property over in Ireland but the agent told me that this weed is present, although he didn't know to what extent. I have found totally different viewpoints on the net. Some say you can treat it yourself others say it is upwards of £20,000 for 100 sq m! as this property is on 1.2 acres and it has been empty for 10 years I think it is likely to be a lot more than 100 sq m. Any advice would be greatly appreciated.
 

Dusty

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From what I understand mate a lot of mortgage lenders won’t touch a property that has knotweed problems.

I’d steer well clear personally.
 

Silver fan 82

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All I know is that it is a nightmare to get rid of mate. Im not even sure that any of the off the shelf chemicals will touch it. Kind of specialist stuff weedkiller wise.
 

ukzero1

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It really is a swine to get shut of. One for the specialists really because if you tackle it yourself and leave just one piece of root in, it'll come back with a vengeance.
Doesn't the agent have pics of the property showing the extent?
 

Marker50

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Can i chirp in.
Is it poss to kill a bamboo.
Cant dig it out its like digging concrete
 

ukzero1

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Can i chirp in.
Is it poss to kill a bamboo.
Cant dig it out its like digging concrete

Yes, but it takes time and patience. A glyphosate weed killer will kill it (Roundup Ultra or Doff Maxi Strength), but may need 2 or 3 treatments, or cut the canes to ground level and treat with a stump and root killer. Again though, may need up to 3 treatments.
 

Marker50

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Ta mate.its about 3 foot at base and about 7 foot high.
Would you lather it in the products mentioned ?
Would that get to the roots.
We took four out about 3 years back ended up using a mini jcb the root system was unreal.
This is last one i thought was the none runner type
 

ukzero1

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Ta mate.its about 3 foot at base and about 7 foot high.
Would you lather it in the products mentioned ?
Would that get to the roots.
We took four out about 3 years back ended up using a mini jcb the root system was unreal.
This is last one i thought was the none runner type

You need to cut it to ground level if using a stump and root killer. ALWAYS follow the instructions on the pack.
Have a look here, it may help...

 

KevinT

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We had this in the back truck yard in a factory I worked in at Bradford, there was the old Clayton to Bradford train line running along side, it came up in the middle of the factory shop floor one summer - right through the concrete floor, the company had to pay specialists and it took them five years to finally give them the all clear. The business got a certificate saying that the weed was removed from the factory grounds, I would suspect that the stuff would be back once it was left to its own devices again. The factory was sold for development and the certificate was need as part of the sale.

It's now a retail park in Lidget Green and I wouldn't be surprised if the shops have plants popping up inside them?:)

KevT
 

ukzero1

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@Dave Spence

It may be worth asking the agent if there is any help (financially) in getting rid of it. If not, look for something else or you're in for a lot of problems over a fairly long time.
 

Dave Spence

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@Dave Spence

It may be worth asking the agent if there is any help (financially) in getting rid of it. If not, look for something else or you're in for a lot of problems over a fairly long time.
Thanks pete, that's what I thought TBH, I think I will probably walk away.
 

emmaemma

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can I just add, if you want to kill the bamboo with stump killer, you are better to do it in autumn when the sap is not rising.
 

JR Hartley

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I currently am treating a few properties with Knott weed I’m ether cut/ lay /spray or injecting into the stems depending on the site I’ve done a few schools which have had to be injected due to location and have a block of flats that’s on its second treatment I’ve always said it’s an on going problem so give yourself time I use round up for 99% and this give great results. Don’t rush when your doing it and keep your eye on growth(s) I will dig out some photos of a private house that I done. We believe the plant was Imported to site by a water company digging up the road some years previous as the house is at the end of the road With very little traffic. What ever you do don’t flail cut it when it’s in seed or you will spread the problem. Cost is dependent on the size of the area that needs sorting
 

Dave Spence

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I currently am treating a few properties with Knott weed I’m ether cut/ lay /spray or injecting into the stems depending on the site I’ve done a few schools which have had to be injected due to location and have a block of flats that’s on its second treatment I’ve always said it’s an on going problem so give yourself time I use round up for 99% and this give great results. Don’t rush when your doing it and keep your eye on growth(s) I will dig out some photos of a private house that I done. We believe the plant was Imported to site by a water company digging up the road some years previous as the house is at the end of the road With very little traffic. What ever you do don’t flail cut it when it’s in seed or you will spread the problem. Cost is dependent on the size of the area that needs sorting
Many thanks for this mate, I suspect it may well be spread over the whole acre.
 
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