New build and Japanese Knotweed.

[Shotinthedark2022]

I wondered if anyone has any experience on buying a new build with japanese knotwood,and Horse tail on the site.
I reserved a property a month ago(bought off plan).They have been pushing for me to exchange.I have now found out this problem exists.The JKW is quite away from my plot.But the HT is running along the frony of my boudary.They are saying that the HT has been treated,but the JKW is still being treated(apparantly it takes a few years to erradicateit) I am concerned that it may come back.I have also heared it can devalue a property.or make it difficult to resell in the future.
Really wondering if i should pull out of the purchase.What would you do .Has anyone any experience?

Yes it all spreads (invasive weed spread and the difficulty in eradication is why it has to be declared) but the owner of the property with it has a legal requirement to control/stop the spread into other properties. The problem is proving it came from next door and it's a potential legal nightmare if your neighbours are arses about it. I believe it's primarily civil law so very expensive to fight and defend. You will also have to declare on your home insurances which can be problematic.

It's more common than people realise and yes it's on a lot of development land. If the developer is removing by digging down 2meters and disposal your likely to be ok (and you should be provided with insurance IF it returned and to assist with you getting buildings insurance). The spread from another property would have to be due to it being really near your border, movement across the two properties (footpaths, animals etc) spreading the plant. HT can spread by spores as well as deep spreading roots which is a problem if it's right near your property.

It's not a complete no no but like I said it's a complicated headache.

Thank you Motherofkevinnotperry, There is a hedge between the plot and the neighbour,and the HT was running all along the hedge that runs in front and is included in my boudary.They are saying it has all been dug out and buried.However,i don't see how they can have got it all out withought digging up the hedge as surely it will be around the roots of the hedge as well??

The HT will be coming back by the sounds of it.
However it’s not exactly Day of the Triffids is it?

We sold a house with JP but we had got it treated with a specialist company over a few years and had a garantee from them. It sold very quickly actually with several good offers but you'll need to start treating it ASAP or rather you need a garantee from them from a specialist company.

If there is still HT in the hedge then you're correct, it's not all gone. I had a very similar jkw situation with a neighbour and it was a pain that went on for years. It is their responsibility to stop it spreading but clearly to they've not done a thorough job. The hedge would be considered as contaminated and need special disposal as well. Obviously adding to the cost as removal costs are based on weight.

The only true way to eradicate HT is apparently a deep dig down and contaminated waste removal off site by professionals who deal with this stuff. It's really expensive (we're into thousands easily), destructive and needs checking for the next few years. Burying it can work but it's still there so disturb it by water levels, digging, building etc and back it comes.

I'd avoid the house based on what you've told me. I'd never want to relive the nightmare years of jkw