Commercial Property News

Japanese Knotweed- understanding the risks

Latest blog from our Commercial Property department.

Japanese knotweed and other invasive non-native species (INNS) are becoming increasingly problematic for property owners and potential investors.

Knotweed was introduced into Great Britain in the 19th century as an ornamental plant. It is now the most invasive plant in the UK. It is a perennial plant that spreads rapidly by its roots and stems and it is incredibly difficult to get rid of.  It can grow up to 10cm a day between its peak growing months of April to October. The roots can extend to a depth of three metres and up to seven metres laterally.  If even a small piece of root or stem is left in the ground, it can re-establish itself in full and spread across the land.  This vigorous growth can wreck foundations, concrete hardstanding and walls, causing considerable damage. The costs of knotweed removal and treatment are substantial. The government has estimated the costs of eradicating it from all of the UK at £2.6 billion.

In the UK there are two main pieces of legislation that cover Japanese Knotweed.  These are:

Wildlife and Countryside Act 1981

Listed under Schedule 9, Section 14 of the Act, it is an offence to plant or otherwise cause the species to grow in the wild.   Section 14 does not impose an explicit obligation to manage Schedule 9 species not introduced onto your land by your own actions. However, the law is not entirely clear as to the full scope of the phrase “causes to grow”.

Further guidance can be found here.

Environmental Protection Act 1990

Japanese Knotweed is classed as ‘controlled waste’ and as such must be disposed of safely at a licensed landfill site according to the Environmental Protection Act (Duty of Care) Regulations 1991. Soil containing rhizome material can be regarded as contaminated and, if taken off a site, must be disposed of at a suitably licensed landfill site and buried to a depth of at least 5 m.

An offence under the Wildlife and Countryside Act can result in a criminal prosecution.  An infringement under the Environmental Protection Act can result in enforcement action being taken by the Environment Agency which can result in an unlimited fine.  You can also be held liable for costs incurred from the spread of Knotweed into adjacent properties and for the disposal of infested soil off site during development which later leads to the spread of Knotweed onto another site.

From a practical point of view any purchaser should identify any INNS on a site prior to exchange of contracts (via survey or appropriate legal due diligence) as this will allow for you to plan for clearing up the infestation and negotiate a contribution towards the costs of this from the seller.

For further information please contact a member of our Commercial Property department.

Myerson are the premier commercial property solicitors in Cheshire and South Manchester. Our expert solicitors can advise on all aspects of commercial property law.

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Myerson Solicitors LLP
Grosvenor House, 20 Barrington Road, Altrincham, Cheshire, WA14 1HB
Tel: +44(0)161 941 4000
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