Don't Tie Yourself In Knots

The Victorians introduced Japanese Knotweed to our shores as an attractive and easy to grow ornamental plant. Little did they know that DEFRA would, in current times, come to estimate the cost of eliminating this evasive plant as £1.56bn. Its proliferation across the United Kingdom is a huge contamination problem for landowners and occupiers.

The problem with this ‘Asian perennial’ is its invasiveness. It thrives on disturbance, growing in any condition and has the frightening ability to break through tarmac and paving slabs and force its way into the foundations of buildings and concrete structures.

In the South West the plant tends to grow on river banks, waste land and railway embankments. However, fly tipping and transporting soil into urban areas means that it is now turning up in all types of locations. Additionally, the development of brownfield sites may mean that knotweed clusters are disturbed.

The problems with Japanese Knotweed are well recognised. The Wildlife and Countrywide Act 1981 states it is an offence to plant or otherwise cause the species to grow wild. The Environmental Protection Act of 1990 class it as “controlled waste” which means that it can only be disposed of in specially licensed landfill sites and needs to be “handled” using special methods.

Finding knotweed on sites can cause huge headaches for landowners and developers. Firstly, there is the cost and time of clearing and decontamination; secondly, it can cause blight on a site and, finally, there is the possible spreading of the problem which can give rise to potential nuisance or neighbour claims.

Specialist contractors can contain, control and clear land effectively but the process needs care. In Devon, sites have been cleared for development but the delay has tied up large amounts of developer funds.

Potentially, it can also affect future house sales if a residential scheme is known to have suffered from knotweed problems in the past.

The problem is such that many commercial and development property buyers are asking for full indemnities and warranties from sellers. The Government has recognised the issue though and is introducing tax incentives in April 2009 to cover the cost of knotweed removal.

Leaseholders can also be affected by the weed. Tenants are invariably required to return a property to their landlord in the condition that it was in at the commencement of the lease. If knotweed appears on a property during a lease term then it could be very expensive for a tenant to eradicate it and satisfy a landlord that a site is then “clean”. Obviously, the wording of a lease will determine the implications for both parties here.

Good advice is available on the Environment Agency and on local authority websites in identifying and treating knotweed For developers, it really emphasises the need for proper land surveys before buying with clear advice given from an environmental expert.

Finally, for soil hauliers, they need to know the law and its implications if they are transporting earth or garden waste.

For further information or advice, contact Keith Biggs

Published 19/06/2008. The author of this article is Keith Biggs