Japanese knotweed could be under control by 2040

Japanese knotweed, the intrusive superweed which strikes fear into the hearts of homeowners, could be under control in 21 years thanks to tighter mortgage lending criteria.

According to research by Environet, a Japanese knotweed removal company, lenders’ strict requirements that Japanese knotweed must be professionally treated before a mortgage will be offered will force homeowners to tackle the problem.

More than 1.2m homes are sold each year in the UK, so by 2040 the vast majority of properties will have been sold once or more, meaning any knotweed infestations will have had to be dealt with.

Current guidelines for Japanese knotweed

Before a mortgage lender will agree to lend, it will require a valuation of the property. If Japanese knotweed is identified by the surveyor, it will be categorised according to the risk it presents to the property.

There are 4 categories, ranging from the presence of knotweed 7 metres from the boundary on a neighbouring property (Category 1), through to it being within 7 metres of the property or already causing damage within the boundary (Category 4).

The more severe the problem, the more likely there is to be an issue with a mortgage lender. Further investigation would normally be required, and a treatment plan may need to be in place before a mortgage is agreed.

Assessing the true impact of Japanese knotweed

A parliamentary inquiry is currently underway by the Science and Technology Committee to investigate the impact of Japanese knotweed, and whether mortgage lending decisions are based on sound scientific evidence.

At a meeting of the Committee on 22nd January, the effect of knotweed on property was discussed, including how quickly it spreads and how it can be managed more effectively.

The Committee raised the impact of Japanese knotweed compared to other invasive plants such as buddleia and bamboo and agreed that there is an “urgent need” for a risk assessment procedure which can be followed to see the actual risk it poses.

The Inquiry is due to publish its findings early this year.

Learn more about Japanese knotweed in our Guide to Japanese knotweed