Japanese Knotweed

Japanese Knotweed (Fallopia japonica)

Probably the best-known and most notorious of all the non-native invasive plant species, feared for its legendary ability to smash through concrete! Introduced by the Victorians, Japanese knotweed spreads rapidly, often along watercourses, forming dense thickets that shade and crowd out our native plants. In winter, it is still easily recognisable as it dies back to leave forests of brown canes.

The plant spreads naturally via its rhizome but also by human action. The tiniest fragment of root or stem carried on machinery or footwear is enough to spark a new invasion. Japanese knotweed contributes to the erosion of our river banks and can increase the potential for flooding. It is capable of causing significant structural damage in the places where it grows and can become a very serious problem for building and development projects. Early and repeated intervention to prevent the spread of this tenacious plant is essential in limiting the long term costs of eradication.

Under new laws it is possible to issue Community Protection Notices against landowners who are allowing invasive non-native plants to spread. For details download Japanese_Knotweed_Community Protection Notices

Download an identification guide here: Japanese Knotweed Identification

Download: Japanese Knotweed Guide to Best Practices

Download: Good Practice Management-Japanese knotweed

Download: IW Council position statement of Japanese Knotweed

Download: EA FAQ Using herbicide in or near water

 

Photo Credit GBNNSS