Japanese knotweed is a tough, invasive plant that causes many headaches for property owners.
It can depress a property’s commercial value, make it hard to get insurance and complicate selling or buying a home. Lenders are often wary of financing properties affected by knotweed, which makes it a serious issue for both homeowners and developers.
This article highlights how Japanese knotweed can affect landowners, provides insight on the Davies v Bridgend County Borough Council case and advises the steps for property owners to take if Japanese knotweed is discovered.
If Japanese knotweed spreads from a landowner’s property onto neighbouring land, that constitutes encroachment and the neighbour could bring an action in private nuisance against the landowner for damages to compensate for the consequential impacts highlighted above. The landowner could also face criminal proceedings if they are found to 'plant' Japanese knotweed or 'cause it to grow'.
A relatively recent Supreme Court case, Davies v Bridgend County Borough Council, has brought welcome clarity on the extent of a landowner’s responsibility for damage caused to their neighbour’s property by encroaching knotweed.
This case concerned the encroachment of Japanese knotweed from the appellant council’s land onto the neighbouring respondent’s land. Although the encroachment started before 2004 it wasn't until 2013, when industry guidance on the risks of Japanese knotweed and the need to implement an effective treatment programme was widely circulated, that the council’s duty of care arose. It was from that point onwards that the council breached its duty of care to the neighbouring respondent by not implementing the treatment programme until 2018.
The neighbour brought a claim of nuisance against the council claiming that his property’s diminution in value was caused by their breach of duty during the period of 2013 to 2018. The Supreme Court held that the council’s breach of duty of care was ‘an irrelevant causative factor’ because the encroachment and resulting diminution in value occurred long before 2013 and any subsequent breach by the council.
Previously, if a property’s value dropped because of knotweed, the owner could automatically claim damages. Following the Supreme Court’s decision in the Davies v Bridgend County Borough Council case, the owner must prove that the damage is directly attributable to the defendant’s breach of duty of care. In simpler terms, they need to show that ‘but for’ the defendant’s breach, the damage would not have occurred.
If a property owner discovers Japanese knotweed on their property, they must take immediate and effective steps to manage it, consulting an expert if necessary. This can help minimise potential legal liabilities.
Sellers must disclose any information about the presence of knotweed on their property when replying to enquiries from the vendor. Failure to do so could make them liable for misrepresentation. This principle, otherwise known as caveat venditor, was reinforced by the very recent case about a moth infestation in a London mansion house. You can read our article about this case here.
Before bringing a claim in nuisance for damage caused by knotweed, the affected party must have evidence that the damage was caused by the neighbouring landowner’s breach of duty of care as per the decision in the Davies v Bridgend County Borough Council case.
Keep up with legal developments related to Japanese knotweed. New cases and rulings can affect a property owner’s rights and responsibilities.
For more information, please contact the property litigation team.
