Invasive weeds: Guidance for the control of invasive weeds in or near fresh water

General methods of control

There are four basic methods of controlling weeds: mechanical, chemical, natural and environmental. Mechanical control includes cultivation, hoeing, pulling, cutting, raking, dredging or other methods to uproot or cut weeds. Chemical control uses specific herbicides. Natural control uses pests and diseases of the target weed to weaken it and prevent it from becoming a nuisance. Environmental control works by altering the environment to make it less suitable for weed growth, for example by increasing or decreasing water velocity.

Users should follow the instructions on the label. In England and Wales the use of herbicides in or near rivers, canals, lakes and drainage channels requires prior agreement from the Environment Agency.

What to do and what not to do


  • take immediate action;
  • contact the Centre for Aquatic Plant Management to confirm identification and the location of the plant;
  • seek advice on correct management for your specific location;
  • obtain approval from the Environment Agency if planning to use herbicides;
  • remove all plant debris from the water after cutting operations;
  • seek advice from the Environment Agency on the disposal of plant material.


  • delay in doing something;
  • allow the plant to spread to nearby water bodies;
  • dispose of cut material in the nearest water body;
  • use invasive non-native species in habitat restoration projects.

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