The results are in! Each spring we commission YouGov to carry out a consumer survey to investigate attitudes towards Japanese knotweed, and this year’s findings, published this week, show a growing pragmatism among homebuyers when it comes to Japanese knotweed.

Almost a third (32%) of British adults who are aware of the invasive plant say they would be prepared to go ahead and buy an affected property, as long as they could negotiate an appropriate discount on the price. So, does this mean Japanese knotweed isn’t the deal-breaker it once was?

Well, awareness is definitely growing (78% of British adults are now aware of Japanese knotweed compared to 76% in 2018 and 75% in 2017) and people are also learning about the treatments and guarantees available, therefore homebuyers have greater peace of mind that it’s a problem that can be solved. As long as there is a professional treatment plan in place with an insurance-backed guarantee, you may not need to walk away from your dream home.

While half (50%) of those who are aware of the plant would not buy a property which had Japanese knotweed, this is significantly less than the 78% who stated they would not buy an affected property two years ago, suggesting people are becoming increasingly pragmatic in their approach to the UK’s most invasive plant.

Of those who said they would proceed with the purchase at a reduced price, the majority (26%) would expect a discount of between 6 – 10%, while 15% would expect to knock off between just 1 – 5%. A further 15% would seek to reduce the price by more than a quarter. In Environet’s experience, a 10% reduction in the purchase price is typical in cases where property has been affected by Japanese knotweed, dropping to around 2-5% if it has been professionally treated.

Nic Seal, Founder and MD of Environet said: “With an estimated 5% of all UK properties now affected by Japanese knotweed, either directly or indirectly, it’s encouraging to see homebuyers becoming increasingly rational in their approach. If left untreated, Japanese knotweed can cause considerable damage to a property which is why buyers and lenders are right to insist that there is a professional treatment plan in place before they agree to proceed. 

“Due to the stigma around Japanese knotweed the property value will almost certainly be impacted, but all that’s required is a sensible renegotiation of the price. People are realising it doesn’t have to be a deal breaker.”

Chartered Surveyor Paul Raine, Director of Expert Surveyors Ltd, added: “The key to selling a property affected by knotweed is a Japanese Knotweed Management Plan from a reputable specialist. Always be honest if the property you’re selling is or has been affected, or it could come back to bite you in the form of litigation from your buyer further down the line.”

According to research carried out by Environet in September 2018, we estimate that approximately 850,000 to 900,000 UK households are affected and suffering an average reduction in value of around 10%, knocking almost £20 billion (£19.8 billion) off property values.