Law and liability
Plain-English summary of the duties that come up most often in Swansea — between neighbours, when selling, and when clearing ground.
There is no law against invasive plants growing on your land. Section 14 of the Wildlife and Countryside Act 1981 makes it an offence to plant or otherwise cause a Schedule 9 species to grow in the wild, which is what tipping, strimming and moving soil amount to in practice.
Under the Environmental Protection Act 1990, knotweed material and knotweed-contaminated soil are controlled waste and must go to a permitted facility with a waste transfer note. It cannot go in a wheelie bin, a green-waste collection, or a skip destined for general waste.
Councils and police in Wales can issue a community protection notice under the Anti-social Behaviour, Crime and Policing Act 2014 where someone unreasonably lets invasive plants affect a neighbour's quality of life. Breaching the notice is a criminal offence with a fine.
Courts have accepted that knotweed encroaching from next door can be an actionable private nuisance, covering treatment costs and sometimes diminution in value. Claims usually turn on whether the neighbour knew about it and failed to act reasonably.
The standard TA6 property information form asks directly whether Japanese knotweed is present. Answering 'no' when you know otherwise risks a misrepresentation claim after completion. A live insurance-backed treatment plan is normally what keeps a sale moving.
Lenders differ, but many surveyors flag knotweed within seven metres of a habitable structure. RICS guidance has moved towards assessing actual damage rather than distance alone, though valuers in Swansea still commonly ask for a treatment plan and guarantee.
Work on or beside a watercourse — spraying, cutting or excavating — may need Natural Resources Wales consent. The Tawe, Clyne, Nant Bran, Nant y Fendrod and Gower brooks are all covered.
This is general information, not legal advice. For a dispute, a sale, or an enforcement notice, take advice from a solicitor and get a survey from a qualified invasive weed surveyor.
