Experts say you need to take immediate action as we reach peak growing season
Neil Shaw Assistant Editor
08:24, 01 Jul 2025Updated 08:43, 01 Jul 2025
Make sure you get rid of it properly
Experts have warned that allowing one plant to grow in your garden could have severe legal consequences – putting you at risk of an ‘Anti-Social Behaviour Order (ASBO)’ or substantial fines of up to £5,000. Garden experts at Japanese Knotweed Ltd say property owners need to take immediate action as the invasive plant season peaks from July.
Ignoring even the slightest spread of the highly destructive weed, or failing to manage contaminated soil, could cost homeowners up to £5,000 in fines. Under reformed government legislation, a Community Protection Notice (CPN) – similar to what used to be known as an ASBO – can now be issued to individuals or organisations who fail to control Japanese knotweed, deeming such inaction as “unreasonable conduct” that negatively impacts the quality of life in a neighbourhood.
Jennifer Holmes at Japanese Knotweed Ltd said: “One of the most asked questions we hear is ‘What damage can knotweed cause?’. Knotweed takes advantage of any weaknesses in buildings, structures and underground infrastructure. If there’s a tiny fracture or crack it’ll grow through it – expanding that crack to cause potentially serious damage.
“We’ve seen concrete broken up, pipes smashed to pieces and even knotweed growing through cracks in walls to invade a kitchen – yes it grew through a crack in the wall and appeared inside a kitchen cupboard. It’s super important to catch knotweed before it gets to this stage, often it’s undetectable to an untrained eye – that’s why calling in a specialist surveyor is your best defense.”
Jennifer explained the consequences of letting the invasive weed spread:
Criminal offence and fines
Government guidelines state that individuals could face fines of up to £20,000 or even a two-year prison sentence if they allow contaminated soil or plant material from any waste they transfer to spread.
CPNs
Failure to control Japanese knotweed can lead to a Community Protection Notice (CPN). A CPN could be used after a mandatory written warning has been served beforehand to get them to stop the anti-social behaviour. Breach of any requirement of a Community Protection Notice, without reasonable excuse, would be a criminal offence, subject to a fixed penalty notice. On summary conviction, an individual would be liable to a fine up to £2,500.
Private nuisance claims
If knotweed spreads from a neighbour’s land onto your property, you may be entitled to make a “private nuisance” claim, potentially leading to a payout for damages and remediation costs.
Property value
Buyers can claim if a seller fails to declare knotweed on property forms (TP1).
Japanese knotweed doesn’t just spread visibly; its underground rhizome (root) can creep across boundaries, causing unseen damage and creating legal disputes. Homeowners are fully responsible for the eradication or control of knotweed on their land.
Japanese Knotweed Ltd shared three steps to take if you spot Japanese knotweed coming in from your neighbour’s property:
Give written notice to your neighbour
If the weed is spreading from an adjoining property, formally inform your neighbour in writing, requesting they take action to treat the knotweed on both their land and yours, and obtain a suitable guarantee for the works carried out.
Get a professional survey
A specialist survey from experts like Japanese Knotweed Ltd will accurately identify the weed and its source, providing crucial evidence for any potential claim or remediation plan.
Act fast
Control methods, such as herbicide management plans or excavation, should be implemented promptly to prevent further spread and avoid legal issues.