Japanese Knotweed
It is not often that the worlds of commercial property and gardening collide but the thorny issue of Japanese Knotweed and how to deal it challenges gardeners, developers and property owners.
Japanese Knotweed is a virulent weed (it grows at a rate of 2 cm per day) with an extensive root system which can cause havoc with concrete foundations, tarmac and drainage systems. The plant was first introduced by the Victorians as an ornamental plant but has subsequently spread throughout the country and is typically found around the rail network and on derelict sites. The plant is easily recognisable during the growing season (April through to June) by it’s distinctive purple stem and tear shaped green leaves. The plant spreads from fragments of existing plants and hence is primarily spread by the uncontrolled dumping. As a result, it is now an offence ‘to plant or otherwise encourage’ the growth of the plant. It has been found extensively on the 2012 Olympic site in east London and experts predict a bill of £70 million to eradicate it.
Disposal of the plant is not a simple process. The plant is classified as controlled waste and only limited numbers of Local Authority waste centres are authorised to handle it. If found on land owned by a business, that business will have a duty of care to dispose of the waste correctly and there are civil and criminal sanctions for its breach.
The most effective option to eradicate the plant is to spray with herbicide. Spraying can take place during the growing season when the shoots are above ground but may take up to three years to fully eradicate.
A quicker method to remove the plant is by digging, however care must be taken to remove all trace of the plant root as a new plant may grow from a ‘pea sized’ piece of root. This method is usually more expensive and impractical, as the roots can extend 7 metres from the plant and up to 3 metres deep.
The overall message is clear. If you suspect that Japanese Knotweed is growing on your land, urgent action should be take to ensure that it is eradicated quickly and in an authorised manner.
