My Neighbour Has Japanese Knotweed: What Can I Do?

Published by PCA Certified Survey Team • Updated October 2026

It is not an offence simply to have Japanese knotweed on your land. However, allowing it to spread into the wild is an offence under the Wildlife and Countryside Act 1981, and letting it encroach onto a neighbour's property can amount to private nuisance. If knotweed is growing next door, or already pushing under your fence, these are the practical steps available in England and Wales.

1. Gather Evidence First

• Photograph the stand, the boundary and any shoots on your side, with dates.
• Measure the approximate distance from the visible growth to your boundary and buildings.
• Get it confirmed by a specialist survey; a written report carries weight with neighbours, insurers and lawyers.

2. Talk to Your Neighbour

Many owners do not know what the plant is. A calm conversation, followed by a polite letter with photos and the survey findings, often leads to a shared treatment plan. Treating both sides of the boundary at once is usually cheaper and more effective than separate jobs.

3. Private Nuisance Claims

In Network Rail v Williams (2018), the Court of Appeal confirmed that knotweed on adjoining land can be an actionable nuisance even before physical damage occurs, because it can reduce the amenity and value of the neighbouring property. Claims can seek the cost of treatment and, in some cases, compensation for loss of value. Take legal advice before starting a claim; costs can be significant.

4. Community Protection Notices

Under the Anti-social Behaviour, Crime and Policing Act 2014, councils and police can issue a Community Protection Notice where someone's conduct, including failing to control invasive plants, has a persistent, unreasonable and detrimental effect on the community. Contact your local council's environmental or anti-social behaviour team if a neighbour refuses to act.

5. Protect Your Own Property

• Do not cut, dig or spray it yourself on their land, and avoid strimming shoots on your side, which can spread fragments.
• Check your home insurance and keep records in case you sell: the TA6 form asks about knotweed affecting the property.
• Ask about a root barrier and a treatment plan with an insurance-backed guarantee for your side of the boundary.