Japanese knotweed (Fallopia japonica)

Japanese knotweed does not produce seeds and spreads from cuttings of rhizome and plant stem. A finger nail piece of plant material is all that is needed for a new plant to grow. Because of this it is essential that Japanese knotweed is controlled correctly.

  • Never throw away or fly tip plant material or soil –  under the Wildlife and Countryside Act 1981, it is an offence “to plant or otherwise encourage in the wild” the growth of Japanese knotweed
  • Avoid strimming, flailing, mowing or chipping Japanese knotweed – pieces of stem as small as a fingernail can grow into new plants
  • Scottish Environment Protection Agency (SEPA) must be contacted before using chemicals in or near water.
  • Removal of plant material off site must be undertaken by a licenced carrier.
  •  Report Japanese knotweed to invasives@annanfisheryboard.co.uk

Key ID Features

Purple speckled stems

Regular nodes (like bamboo)

Creamy clusters of flowers (Aug to Oct)

Ability to grow through weaknesses in concrete and asphalt

Large shield shaped leaves - can grow up to 120mm long

Flat at base of leaf

  • Spraying with a commercial glyphosate-based chemical is effective on Japanese knotweed. Spraying needs to take place at least twice during the growing season, once the plant is fully in leaf but before flowering. Over a period of 5 to 7 years the plant will be controlled although eradication is unlikely. The area needs to be checked annually to treat small areas that may have re-sprouted.
  •  Injecting the plant with a stem injection unit is very effective and can reduce the plant in size by as much as 95% in one year. This works by injecting a measured dose of herbicide into each cane of the Japanese knotweed infestation which allows the herbicide to translocate throughout the roots and rhizome of the plant.
  • Grazing will suppress growth but cannot completely eradicate the plant.

Best Methods of Control

Do's & Don'ts

Report an Invasive Species


Tel: 01576 470600


email: invasives@annanfisheryboard.co..uk

Contact Us


Fisheries Office
Annandale Estates, St Ann's
Tel: 01576 470600

Mobile: 07710331079


Get your copy of the Fisherman's Guide to the River Annan




© 2018 by River Annan Trust

  • Wix Facebook page
  • Wix Twitter page
  • YouTube Classic