UKThere's Japanese knotweed on my neighbour's land spreading to mine. What can I do?
You may have a private nuisance claim against your neighbour if Japanese knotweed from their land encroaches onto yours and causes damage or interferes with your use of the land.
What the Law Says
While the Law of Property Act 1925 s. 62 deals broadly with conveyancing and the passing of easements and profits upon conveyance, it does not directly address Japanese knotweed or nuisance. The relevant legal framework for knotweed encroachment comes from common law — specifically the tort of private nuisance — not s. 62.
Japanese knotweed is not illegal to have on your land, but allowing it to spread onto neighbouring property may make the owner liable in private nuisance.
To succeed in a nuisance claim, you must show the knotweed has caused substantial interference with your enjoyment or use of your land — for example, by damaging foundations, drains, or paving, or significantly reducing property value.
Crucially, courts have confirmed that physical invasion (e.g., roots or rhizomes crossing the boundary) is not required: mere presence and risk of serious harm can suffice, especially where treatment has been neglected.
What Courts Have Said
Courts have clarified that Japanese knotweed’s invasive nature triggers liability even without immediate physical damage — its presence alone can constitute a nuisance if it materially affects land use or value.
Held that Japanese knotweed encroaching from adjacent land onto claimants’ properties amounted to private nuisance, even without proven physical damage — the plant’s presence and capacity to cause serious harm was sufficient interference.
Awarded damages and injunction requiring removal after knotweed spread from defendant’s garden, causing structural concerns and devaluing the claimant’s property.
What to Do
Take clear photos and date-stamped video of the knotweed on both properties, especially where it crosses the boundary.
Write to your neighbour formally requesting they treat the knotweed using a PCA-accredited contractor and provide a management plan.
If they refuse or ignore you, instruct a surveyor to produce a Japanese knotweed report assessing spread, risk, and treatment costs.
Consider mediation first — many disputes resolve without court.
If necessary, issue a claim in the County Court for nuisance, seeking an injunction and/or damages (within 6 years of knowing the problem).
Sources
Not legal advice. This article is general information based on publicly available sources, written for educational purposes. Laws change and individual situations vary. Consult a licensed attorney in your jurisdiction before acting on anything you read here. Last reviewed: 2026-06-08.