Japanese knotweed

What should you ask if the seller says they dug the knotweed out and there is no paperwork?

Ask where the soil went and who did the work. GOV.UK says you must not let Japanese knotweed spread and you must not put it in the green waste. Dug soil can still contain rhizome. A cleared bed with no waste note and no specialist report is not a management category and not a completion certificate.

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?

The RICS journal still expects a remediation specialist where knotweed is seen within the boundaries, and a management plan is the usual paper trail when treatment has happened. “We dug it out” is not that plan. Rhizome can remain, and the waste is a controlled matter if it leaves the site. The surveyor, seeing bare soil, cannot confirm the plant has gone.

Do not fill the bed with new shrubs and treat the problem as closed. Ask for any consignment notes, herbicide records and guarantees. If none exist, commission an identification and advice before exchange if the sale depends on it. There is no RICS price for excavation. Specialists quote the area. A missing note does not by itself prove the plant is still there.

What should you ask your surveyor?

When was it dug, and by whom?
Where did the soil go, and is there a waste note?
Can you see regrowth today, or only disturbed ground?

What are the typical next steps?

Do not rake the soil into the neighbour’s side or into a skip as ordinary rubbish.
Ask the seller for papers before you agree a price. A verbal clearance is not a category.
If you need comfort, get a specialist to look. The survey has not certified the ground.

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 herbicide without a plan count?

A bottle and a date are not the management plan the standard is written around. Ask what was sprayed, how often, and what remains.

Can knotweed be composted if it looks dead?

GOV.UK’s spreading rules are there because dead-looking material can still spread. Do not compost it.