Japanese Knotweed and the Wildlife and Countryside Act 1981
In the 1800s the deceptively attractive Japanese Knotweed was introduced to Great Britain from Japan as an ornamental plant. It has very few predators in this country and, therefore, is difficult to control naturally.
Unlike most plants, Japanese Knotweed does not need both male and female plants to reproduce; nor does it rely on the production of seeds. It can grow and regenerate simply through the transferral of pieces of plant or root from place to place – for example, through garden clearance and subsequent disposal. With its reputation of being able to grow 2cm or more in a day, and the roots being able to grow to a depth of 3m, it is easy to understand why it is so difficult to control.
In addition to the speed of growth, it has a particularly sturdy nature. It is not deterred from harsh conditions; it is able to push its way through asphalt or concrete and is not afraid to tackle retaining walls or drains. Its ability to cause damage to structures can have serious impacts on marketability of property and accessing adequate insurance, and it is renowned for being time consuming and expensive to treat.
From a legal perspective, Japanese Knotweed is addressed – along with other invasive non-native species – in both European and national legislation. Nationally, Part II of Schedule 9 of the Wildlife and Countryside Act 1981 (WCA81) lists a number of plants that have been introduced and become established in the UK, which the Government is trying to prevent from spreading any further. Japanese Knotweed is one of those plants listed.
If the knotweed is already growing in a garden (and has not been specifically introduced) there are expectations that the owner/occupier of the property will need to manage and control it so as not to let it spread into the wild. If there is failure to take reasonable steps to control the plant from spreading into the wild, however, this could amount to an offence under section 14(2) of the Wildlife and Countryside Act 1981, namely planting or causing Japanese Knotweed to grow in the wild.
It is important to be able to demonstrate that all reasonable steps have been taken to control the plant from spreading. Equally, it would be prudent for a homeowner or occupier not to allow Japanese Knotweed to spread into neighbouring land for fear of being subject to a claim in private nuisance.
Williams v Network Rail Infrastructure Ltd  UK CC (2 February 2017)
In this recent case the court decided that Network Rail Infrastructure’s land was causing a blight on neighbouring land owned by the claimants, Mr Williams and Mr Waistell. For the last 50 years the land owned by Network Rail Infrastructure had been infested with Japanese Knotweed which had spread to the claimants’ land. They claimed that not only had the knotweed interfered with the quiet enjoyment of their land but also affected its value. The claimants were able to demonstrate that the interference was reasonably foreseeable by Network Rail Infrastructure and that it had failed to take all reasonable action to prevent the interference. It was determined that the knotweed was an actionable nuisance because it affected the amenity value of the claimants’ land and caused a reduction in value. The claimants were awarded damages for the cost of the surveys, treatment and insurance backed guarantees for the knotweed, any residual reduction in the value of their properties after treatment and general damages for the loss of amenity and quiet enjoyment of their land.
The UK Government provides online guidance about how to manage Japanese Knotweed and prevent it from spreading:
If you are thinking of selling your home and are concerned about the presence of Japanese Knotweed, you can commission a specific survey to identify whether it is present and, if so, what measures you should take to manage or remove it. If you choose to have it professionally removed or treated, the team undertaking the works would normally be able to give you a guarantee. If a guarantee is provided, it will be helpful if it can be assigned to a third party, such as a prospective purchaser
If you would like further information or have any concerns regarding Japanese Knotweed please do not hesitate to contact us.
Jane Haviland Webster is a trainee solicitor at Barker Gotelee Solicitors.