Skip to content It’s a question we’re often asked, and the answer is – it depends! So we’ve teamed up with expert surveyors who undertake property valuation reports in the UK and created a valuation impact model that gives indicative price reductions.
Japanese knotweed is an invasive plant species that poses significant challenges for homeowners and property sellers in the UK. Its rapid growth and ability to cause structural damage make it a serious concern for mortgage lenders and buyers alike. Below are the key ways Japanese knotweed can affect property values and marketability.
Japanese knotweed is notoriously difficult to eradicate. Professional treatment programmes can range from £2,000 to over £20,000, depending on the extent of the infestation and the method of removal. Mortgage lenders often require a formal treatment plan with an insurance-backed guarantee before approving a loan, adding to the overall cost.
The presence of Japanese knotweed carries a strong stigma. Many buyers are hesitant to purchase a property with a known infestation, fearing structural damage and future growth. This can significantly reduce the pool of potential buyers, making it harder to sell.
Properties affected by Japanese Knotweed often suffer a 10–15% reduction in market value. Even after successful treatment, the history of infestation can deter buyers and affect price negotiations. Some sellers may have to accept lower offers or wait longer to find a willing buyer.
KnotSure gives an indicative valuation and includes revised valuations for the property if it has the benefit of a 10-year IBG following either herbicide treatment or physical removal.
For high-value properties the extra cost of physical removal over herbicide treatment is often justified on purely economic grounds, when the residual diminution is considered. Removing the problem minimises the blight.
Actual market price, as opposed to a valuation, is the price that a willing buyer and a willing seller agree to – they are not necessarily the same!
Call or email to speak to the specialists
Our team of experts is available between 9am and 5:30pm, Monday to Friday to answer your enquiries and advise you on the next steps
Want a survey?
If you already know you have an invasive plant problem, you can request a survey online in less than two minutes by providing a few brief details. A member of the team will swiftly come back to you with further information and our availability.
Need quick plant identification?
Simply upload a few images of your problem plant to our identification form and one of our invasive plant experts will take a look and let you know, free of charge what you are dealing with. We’ll also be there to help with next steps where necessary.
