When Beginning a residential property transaction, there are numerous factors to consider, including location, price, and condition. However, there is one invasive plant that has become a growing concern for property owners and potential buyers alike – Japanese Knotweed. This relentless, fast-growing plant has the potential to wreak havoc on properties, causing significant damage and affecting the value of homes across the country. In this blog post, we will explore the impact of Japanese Knotweed on house purchases and sales.

Understanding Japanese Knotweed

Japanese Knotweed (Fallopia japonica) is a perennial plant native to Eastern Asia. Introduced to the UK in the mid-19th century as an ornamental plant, it has since become one of the country’s most invasive and destructive plant species. Japanese Knotweed spreads rapidly through its extensive underground root system, known as rhizomes, and can grow up to three meters in height.

The Impact on Residential Property Transactions

1. Lenders’ Concerns: Japanese Knotweed has become a red flag for mortgage lenders, as its presence near a property can affect its structural integrity and value. Lenders are cautious about providing loans for properties with known Japanese Knotweed infestations or even suspected sightings. They fear the potential costs associated with eradication and the possibility of devaluation.

2. Property Valuation: The presence of Japanese Knotweed on or near a property can significantly impact its market value. Surveyors and valuers are trained to identify and assess the severity of infestations. A property affected by knotweed may be devalued, sometimes by as much as 10% or more. This reduction can make selling the property more challenging and potentially lead to extended negotiation periods.

3. Insurance Considerations: Insurance companies are increasingly concerned about the risks associated with Japanese Knotweed. Policies may exclude coverage for any damage caused by the plant or refuse coverage altogether for properties affected by an infestation. Homeowners may face difficulties in securing adequate insurance or may have to pay higher premiums due to the presence of knotweed.

4. Legal Obligations: Sellers have a legal obligation to disclose the presence of Japanese Knotweed on their property to potential buyers. Failure to do so can lead to legal disputes and claims of misrepresentation. It is crucial to involve legal professionals and surveyors to ensure all parties are aware of any knotweed issues.

Managing Japanese Knotweed

a. Professional Eradication: Dealing with Japanese Knotweed requires professional expertise due to its aggressive nature. Attempting to remove it without proper knowledge can lead to regrowth and further spread. Consult with specialists experienced in Knotweed management who can employ effective eradication methods such as herbicide treatment or excavation and removal.

b. Mortgage Lender’s Approval: When dealing with Japanese Knotweed, it is essential to work closely with your mortgage lender. Obtain their consent and follow their guidelines for treatment and eradication. Some lenders may require a management plan or a guarantee from an approved contractor before approving a mortgage application.

c. Ongoing Monitoring: Japanese Knotweed can be persistent, and diligent monitoring is crucial even after eradication. Regular inspections and maintenance can help prevent regrowth and provide peace of mind to potential buyers.


Japanese Knotweed has become a significant concern for property transactions. Its destructive nature and potential impact on property values have made lenders cautious and raised the importance of proper disclosure and professional eradication. Understanding the implications of Japanese Knotweed and working with experts can help mitigate its effects and ensure a smoother property transaction process.

If you need to discuss the above with a solicitor, call us on 0161 850 9911 and ask to to speak to one of our conveyancing team.