Japanese knotweed

Can Japanese knotweed be missed on a winter inspection?

Yes. The canes die back in winter and the live growth is underground, so a survey in January can miss a stand that would be obvious in July. A winter visit that says knotweed was not seen is not a certificate that the ground is clear.

Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.

What is the fuller explanation?

RICS surveyors report what they can see. The 2022 professional standard is about how to report knotweed when it is identified, including management categories and a recommendation to take specialist advice. It does not give the surveyor x-ray vision in February. Dead canes, bamboo-like stems and crown material can still be visible if you know what to look for, and they can also be hidden under brambles or on land the surveyor could not enter.

GOV.UK tells owners not to let Japanese knotweed spread and explains that soil and plant material are not ordinary garden waste. That duty is not something the survey enforces. If you are buying on a summer completion after a winter survey, say so to your solicitor. A specialist inspection in the growing season is a further instruction, not a rewrite of the winter report.

What should you ask your surveyor?

What season was the inspection, and what growth could you actually see?
Which parts of the garden were overgrown or not entered?
Would you still want a specialist if the seller has said the garden is clear?

What are the typical next steps?

Do not treat “none seen” in winter as a guarantee.
Ask the seller, in the property questions, whether knotweed has ever been identified. The survey is not that form.
If the answer is yes, or the garden was hidden, ask a remediation specialist rather than another general survey in the same season.

Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.

Also asked about this

Does the 2022 standard require a summer visit?

No. It tells the surveyor how to report what is identified. It does not change the season you booked.

Can snow cover the evidence?

Yes. Covered ground is a limitation. Ask the surveyor to say so if that was the case.