Legislation makes it an offense to allow Japanese Knotweed to grow wild and if transported off site, there is a duty of care not to cause harm to human health or the environment.
Japanese Knotweed, its spread, handling and disposal are covered by a range of legislature. The following are some of the most pertinent to the homeowner or developer.
Under the Wildlife and Countryside Act 1981 you would be breaking the law if you allowed Japanese Knotweed on your property to spread into the wild. This would include allowing the planted its rhizomes (which can extend 7m underground) to spread from your property, or construction site, into neighbouring land.
Once dug up or cut down, any waste containing Japanese Knotweed becomes controlled waste and is subject to legislation under the Environmental Protection Act 1990. This legislation places a duty of care for its handling and disposal. The waste must be taken to a licenced landfill site by an appropriately registered carrier.
The Anti-Social Behaviour, Crime and Policing Act 2014 could be used when a neighbour “fails to act” when ordered to control Japanese Knotweed. A Community Protection Notice could be issued requiring action to be taken and breach of any requirement would be a criminal offence.
Under common law, with respect to private nuisance, an offence may have been committed by anyone causing a substantial and unreasonable interference with another person’s land. Where reasonable action is not taken to remediate the nuisance, common law may apply.