Habitat

Common on waste land, railways, road sides and river banks.

Key ID features

• Grows in dense thickets reaching 2.5-3m in height.

• Stems are purple-speckled, bamboo-like growing in a zig-zag shape. 

• Leaves are shield shaped and lush green. New growth is spear shaped.

• Large tassels of white flowers are produced in summer.

Distribution

Widespread and common across the UK.

Impacts

Outcompetes native flora, contributing to river bank erosion, increasing flood risk and damage to existing structures (it can grow through asphalt, concrete and brickwork).

Do’s & Don’ts

• DO see NRW’s webpage ‘Japanese knotweed: what you need to know’ for information on preventing the spread and control of Japanese knotweed: www.naturalresources.wales

• DO safely contain and dispose of Japanese knotweed at a licensed disposal site in line with waste legislation.

• DON’T try to dig up, flail, mow or chip Japanese knotweed. Even a tiny fragment of the cut rhizome can re-grow.

• DON’T spread soil contaminated with Japanese knotweed rhizome - the knotweed will re-grow. 

• DON’T take Japanese knotweed to recycling centres that receive garden waste as it will contaminate the compost.

• DON’T break the law - Don’t dump garden waste contaminated with Japanese knotweed in the countryside. If you cause Japanese knotweed to spread you may be guilty of an offence under the Wildlife and Countryside Act, 1981.

More Information

For more information visit the GB Non-Native Species Secretariat website.