Japanese Knotweed Check
Check any UK property for Japanese knotweed. Searches open source records within a 5-mile radius of the property — knotweed can affect your mortgage, insurance, and legal obligations.
Data sourced from publicly reported sightings. Most infestations are recorded, but physical surveys are recommended for certainty — not all knotweed is reported.
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Japanese Knotweed FAQ
How accurate is this check?
This tool searches open source records of Japanese knotweed sightings within a 5-mile radius of the property. While the majority of infestations do get reported — particularly those flagged during surveys or by councils — some infestations are never formally recorded. A clear result is reassuring but does not replace a physical invasive plant survey.
Can Japanese knotweed stop me getting a mortgage?
Yes. Most high-street lenders will decline or restrict a mortgage if Japanese knotweed is present within 7 metres of the property boundary. Some lenders require a professional management plan and insurance-backed guarantee before proceeding.[2]
Does Japanese knotweed have to be disclosed when selling?
Yes — sellers must declare Japanese knotweed on the TA6 property information form. Failing to disclose known knotweed is a misrepresentation and can result in legal action after completion. Even if you treat it before sale, it must still be disclosed.[1]
How much does Japanese knotweed affect property value?
Studies suggest Japanese knotweed can reduce property value by 5–15%. Beyond the direct devaluation, it affects buyer confidence and can significantly narrow the pool of mortgage lenders, effectively reducing demand.
What does Japanese knotweed look like?
In spring it emerges as red/purple shoots. By summer it grows into dense bamboo-like canes up to 3m tall with large heart-shaped leaves and creamy-white flowers. It dies back in winter but the roots (rhizomes) can survive for decades and regrow from fragments as small as 1cm.
How is Japanese knotweed treated?
Professional treatment typically involves herbicide injection or spraying over 3–5 years, or physical excavation and removal (more expensive but faster). Costs range from £2,000 for small infestations to £20,000+ for large ones. Always use a Property Care Association (PCA) accredited contractor.
Further reading
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Free to startExact count of recorded sightings within the 8km (5-mile) search radius and the precise distance in metres to the nearest recorded occurrence — the full dataset behind the detection result.
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