In 40 seconds
Japanese knotweed (Fallopia japonica) is an invasive plant that spreads underground through a tough rhizome system and is very hard to remove without specialist help. It is not illegal to have it on your land, but you must not allow it to spread — and you must disclose it when selling a home. The realistic options are a herbicide programme over about three seasons or full excavation, both best carried out by a PCA-accredited specialist. A house with knotweed is usually still mortgageable with a professional treatment plan backed by an insurance-backed guarantee. The single most important step is an accurate survey.