Does home insurance cover Japanese knotweed?

Finding knotweed is annoying enough without learning your insurer probably won’t help. But it’s worth knowing why, because the reason tells you where to look next. And there are a few things you can do before spending anything.

If you’re new to the subject, our Japanese knotweed overview covers the basics.

Why home insurance usually doesn’t pay for it

Knotweed is a plant that grows and spreads over time. That’s a different kind of problem from the sudden events, like a fire or a burst pipe, that most people picture when they think about claiming.

How your own policy treats it comes down to the wording. Insurance-backed guarantees do exist, but they come with treatment rather than with your home insurance. RICS describes them as a guarantee from the treatment firm to come back and re-treat any regrowth, usually for at least five years after the work is finished, with a separate insurance policy that keeps the guarantee valid if the firm stops trading.

So “usually not” really does mean usually. Your policy is the only thing that gives you the answer for your home.

What to do next

Start by reading your policy wording. That’s the full document, not the one-page summary, and yes, it’s longer than you’d like. Look for the exclusions section and search it for “knotweed”, “invasive plants”, “plants” and “gradual”. Note the page and clause number of anything relevant.

If your insurer says no and you think the wording supports you, you can complain to them. If they don’t put it right, you can take your complaint to the Financial Ombudsman Service, which is free. You can do that once you’ve had the insurer’s final response, or if 8 weeks have passed without one. You have 6 months from the date of the final response to bring it.

For many people the answer at this stage is simply “not covered, so it’s on me”. That’s not a dead end. It just means the next decision is about how to deal with the plant, and that’s a decision you get to make.

When a specialist helps

You don’t need a specialist to read your policy or ask your insurer a question. Where one earns their place is in the next step: confirming it really is knotweed, mapping how far it has spread and setting out a plan to deal with it.

A Japanese knotweed survey is usually the place to start. It gives you something in writing, which helps if you later talk to a neighbour, a buyer or a lender. HomeOwners Alliance puts a survey by a Property Care Association-accredited specialist at from around £250 plus VAT, depending on the property and where it is (2026).

Ask for the findings in writing, separate from any quote for treatment, so you can compare before you agree to anything.