Tightening the knot(weed)
5th September, 2018
What is Japanese knotweed and why is it a problem for land owners?
Japanese knotweed is an invasive non-native species of plant introduced into the UK as an ornamental plant in the 19th century. It is a perennial plant that spreads rapidly by its roots and stems and is extremely difficult to eradicate from land.
It can grow more than a metre a month and its vigorous roots and top growth can penetrate foundations, concrete hardstanding and walls, causing considerable damage and weakening of structures. As a result, the presence of Japanese knotweed on land can adversely affect the value, marketability, and insurability of affected land and buildings and make it much more difficult to sell or obtain a mortgage.
An owner or occupier is not legally obliged to control, remove or treat Japanese knotweed on their land but if sufficient steps aren’t taken by that owner or occupier to prevent the knotweed spreading on to neighbouring land then they could find themselves facing a private nuisance claim
Network Rail Infrastructure Ltd v Williams & Waistell 
In February 2017 two homeowners were awarded damages by Cardiff County Court for unlawful interference with the use and enjoyment of their property as a result of the presence of Japanese knotweed on Network Rail’s land immediately behind the properties of the two homeowners.
Network Rail had sought to challenge this decision but the Court of Appeal dismissed their appeal earlier this year.
Importantly, and in contrast to the findings of the original county court judgement, the Court of Appeal held that there was no requirement for any physical damage to property for the encroachment of the knotweed to be actionable.
The Court of Appeal noted that Japanese knotweed carries the risk of future physical damage to buildings, structures and installations on the land. In addition, the presence of Japanese knotweed rhizomes (the underground stems of the plant) on the land belonging to the homeowners imposed an immediate burden on the owner of the land in terms of an increased difficulty in the ability to develop, and in the cost of developing the land, should the owner wish to do so. Any improvement or alteration of the property required removal of contaminated soil by special, and probably expensive, procedures. For those reasons, Japanese knotweed and its rhizomes were a “natural hazard” which affected the owner’s ability to fully use and enjoy the land.
In this case a nuisance was committed where the encroachment of the rhizomes diminished the utility and amenity of the land even though there was no physical damage at the time.
The Court of Appeal was satisfied that Network Rail had actual knowledge of the presence of Japanese knotweed on its own land, that it ought to have been aware of the risk of damage and loss of amenity to adjoining properties and that it had failed to take reasonable steps to prevent the resulting interference.
Don’t ignore it
Buyers, tenants and owners of property affected by Japanese knotweed should take note of this decision and ensure that prompt and effective action is either being taken or will be taken in respect of any Japanese knotweed and/or its rhizomes on their land, particularly near to borders with neighbours . Failure to establish its presence or to take any action once it is present could be a costly mistake.
If you require any further information on this issue, please do not hesitate to get in touch.
Please note that this briefing is designed to be informative, not advisory and represents our understanding of English law and practice as at the date indicated. We would always recommend that you should seek specific guidance on any particular legal issue.
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