Japanese knotweed is now widespread across the UK. There have been many scare stories in the press about it causing all manner of serious structural damage to property, but the reality couldn’t be much further from the truth. Current studies indicate that actual structural problems arising from knotweed are extremely rare, and in fact there are many other forms of vegetation which can cause far more harm.

Concern has been raised over recent years that mortgage lenders and valuers were unnecessarily declining residential properties affected by Japanese knotweed.  Such lending policy was blighting large sectors of housing stock and preventing sales, even if there was no evidence of any physical or structural damage.

In order to address this, last year’s RICS Guidance Note for valuers aimed to help mortgage lenders to grant more mortgages on affected properties. This was on the condition that control measures were in place, and account had been taken by the valuer in terms of any diminution of value. The identification of knotweed it was hoped, should no longer be a death sentence to a potential sale.

The guidance still places a clear duty on a valuer/surveyor to identify Japanese knotweed during their inspection, and to take into account any loss of amenity in their valuation, even if there is no physical damage to a structure. I would therefore argue that it does little to protect a surveyor, previous owner or neighbouring land owner against a future claim. Two recent cases highlight this fairly well, and suggest that the anxiety around Japanese knotweed is still very much alive and kicking.

The first is the recent Court of Appeal ruling in Davies v Bridgend County Borough Council (2023) in which Mr Davies has won damages £4,900 due to the presence of Japanese knotweed spreading from council owned land adjoining his rear garden. There was no indication that it had in any way threatened the structure of his property, but he successfully argued that it had affected the amenity of his land.

We have also seen recent damages in the case of Downing v Henderson (2023) where a purchaser of a property was awarded £32,000 by a vendor who failed to disclose the presence of Japanese knotweed growing at the bottom of his garden to a purchaser prior to sale. Again, there was no evidence of structural damage.

Despite the lack of evidence of structural damage and attempts to play down the effects of this invasive plant has on the mortgagability of a property, one could still argue that its influence is still causing nervousness amongst the general public.

I would love to see a more relaxed approach to this ubiquitous species which causes little structural damage and can be successfully treated. People’s perception needs to change before we see any real progress in reducing claims. However, until that happens and as a residential surveyor, I have no intention of dropping my guard anytime soon.