Japanese knotweed: Lenders branded ‘overly cautious’


The Science and Technology Committee has called for more academic research into the effects of the destructive weed on buildings and wants to learn more from the approach of international lenders.

In its response to an inquiry held in January, the committee agreed the presence of Japanese knotweed could have a ‘chilling’ effect on the sale of a property and was hard to eradicate compared to other plants. It also acknowledged the added threat that it could regrow.

But it described mortgage lenders in the UK as being overly cautious and said their counterparts in other countries did not treat the plant with the same degree of concern.

It wants lenders to use a more ‘measured and evidence-based approach’ when making lending decisions involving homes with the threat of Japanese knotweed.

And the committee has recommended Defra (the Department for the Environment, Food and Rural Affairs) carries out a study of international approaches to Japanese knotweed and how they impact on property sales to inform discussion.

Caution justified

But Nic Seal, founder and MD of Environet, a Japanese knotweed removal specialist, defended the UK lenders and questioned whether public money should be spent on the research.

“Lenders are right to be cautious when it comes to lending on properties affected by Japanese knotweed,” he said, “bearing in mind the damage the plant can cause and the difficulty entailed in killing or removing it. Personally, I think most lenders have their policies about right.”

He added: “The UK is probably the worst affected country; we’re not aware of any other country putting restrictions on mortgages due to knotweed, but that is why their knotweed industries are non-existent or in their infancy. The UK is considered to lead the world in knotweed eradication.

“More public money for DEFRA research? I’m not convinced it’s necessary, instead let’s continue to lead the fight against knotweed to protect home-owners and lenders from this aggressive and destructive plant.”

Collaborative approach

His comments were echoed by Mark Montaldo, solicitor and head of litigation at KnotweedHelp.com who said the guidelines were cautious for a reason.

He reported there had been many cases where knotweed had caused damage to property and without effective treatment it had continued to grow and blight the building.

“We agree that more research is needed, but it is wrong to say mortgage lenders and homeowners are relying on incorrect scientific advice,” he said.

“What we need is a more collaborative approach to gathering and studying evidence from the past few decades, and a stronger focus on regulations for treating knotweed. It is only with effective treatment that we can combat the spread of knotweed and stop it from becoming a bigger problem than it already is. ”

An overview of the report

In its report the committee raised the following points:

  • When there are disputes, mediation rather than litigation should be offered in the first instance
  • Royal Institution of Chartered Surveyors (RICS) risk assessment framework for Japanese knotweed ensured more lenders were lending against affected properties so long as there were funded treatment plans and insurance-backed guarantees in place.
  • The ‘seven-metre rule’ was causing problems in housing transactions. The committee said this was a ‘blunt instrument’ and RICS was meeting to update its framework in relation to this. Japanese knotweed is currently considered to be a risk to buildings which are within seven metres of the plant.

Rt Hon Normal Lamb MP, chair of the Science and Technology Committee, said: “We need an evidence-based and nuanced approach to the issue, one that reassures owners and buyers that they will not be subject to disproportionate caution when trying to buy or sell a property.”


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