Scope: England and Wales. The Wildlife and Countryside Act 1981 and the environmental duties apply across both. Verified against the legislation on 14 August 2026.
Two things are true at once and landlords routinely believe only the second:
- Having Japanese knotweed on your land is not an offence. You are not required to remove it.
- Causing or allowing it to spread is, and letting it reach a neighbour is a civil claim on top.
The risk is therefore about management and disclosure, not eradication.
The offence
Under section 14 of the Wildlife and Countryside Act 1981 it is an offence to plant or otherwise cause Japanese knotweed to grow in the wild. In practice that reaches:
- Cutting it and leaving the cuttings where they can root.
- Moving contaminated soil.
- Fly-tipping arisings — knotweed waste is controlled waste and must go to a licensed facility.
Which means the dangerous act is usually an attempt to deal with it badly, not leaving it alone. A tenant strimming it and putting it in the green bin is the classic route to an offence, and it happens because nobody told them.
The neighbour claim
Knotweed encroaching on adjoining land, or reducing its value by its presence at the boundary, supports a claim in private nuisance. Damages can include treatment costs and, in some circumstances, diminution in value.
The critical point for a landlord is that you do not escape this by not living there. Liability follows the person who has control of the land, and letting the property does not transfer that in the way landlords assume.
Disclosure, and where it bites
On a sale, the standard property information form asks directly about knotweed. Answering "no" when you knew, or answering "not known" when you had been told, is misrepresentation — and it is one of the more frequently litigated. It can support rescission or damages long after completion.
For a letting, there is no equivalent prescribed form, but:
- Telling the tenant is the practical way of stopping them making it worse.
- An untreated infestation affecting the property's amenity can engage hazard and repair questions where it damages the structure.
- A management plan you can produce is what a buyer, lender or insurer will ask for — see selling or refinancing.
Mortgages and insurance
Lenders take knotweed seriously and many will decline or require a treatment plan with a guarantee before advancing. That makes it a refinancing problem as much as a gardening one.
Insurers generally do not cover knotweed damage, and an undisclosed known infestation can affect a claim — consistent with how landlord cover actually works.
What to do if you find it
- Identify it properly. It is frequently confused with bindweed and dogwood. A misidentification costs either an unnecessary treatment plan or an ignored real one.
- Do not cut, strim or dig it, and tell your tenant and your gardener the same, in writing.
- Get a professional treatment plan from a specialist, with an insurance-backed guarantee — the guarantee is what lenders and buyers want to see.
- Record everything: photographs with dates, the plan, the treatments, the guarantee. See record keeping.
- Tell your neighbour if it is near a boundary. It is uncomfortable and it is far cheaper than the nuisance claim.
- Disclose it when asked, on any sale, and do not be tempted by "not known".
Treatment is usually multi-season herbicide rather than excavation, because removal generates controlled waste at significant cost.
Run the free compliance check for the duties that attach to your property.
Common questions
Is it illegal to have Japanese knotweed?
No. Having it on your land is not an offence and you are not required to remove it. What is an offence, under section 14 of the Wildlife and Countryside Act 1981, is planting it or otherwise causing it to grow in the wild — which in practice means spreading it: leaving cuttings where they can root, moving contaminated soil, or disposing of arisings as ordinary waste when knotweed waste is controlled waste.
Can my neighbour sue me over knotweed?
Yes. Encroachment onto adjoining land, or its presence at the boundary reducing that land's value, supports a claim in private nuisance, with damages that can include treatment costs and sometimes diminution in value. Letting the property does not move that liability the way landlords assume — it follows control of the land.
Do I have to tell a buyer about knotweed?
When asked, yes — and the standard property information form asks directly. Answering "no" when you knew, or "not known" when you had been told, is misrepresentation and is among the more frequently litigated disclosure failures. It can support rescission or damages long after completion.
What should I do if I find knotweed at a rental property?
Identify it properly first, because it is often confused with bindweed and dogwood. Then do not cut, strim or dig it, and tell your tenant and gardener the same in writing — an attempt to deal with it badly is the usual route to an offence. Get a professional treatment plan with an insurance-backed guarantee, because that guarantee is what lenders and buyers ask for, and record everything with dated photographs.