Japanese Knotweed has been targeted for removal Picture:PA
Volunteers are working with the Environment Agency in Bristol to stop the non-native invasive weed known as Japanese Knotweed choking waterways.
The Avon Invasive Weed Forum hopes to remove as much non-native invasive weed from the south west of Bristol along the Malago and Pigeonhouse streams.
They will also tackle other plants such as Himalayan Balsam and Giant Hogweed.
Giant Hogweed can cause blistering of the skin and there are laws against causing its growth in the wild.
Guy Pluckwell, from the Environment Agency said: 'Non-native invasive weeds can cause a nightmare for waterway management.
"They have the potential to grow at an incredibly fast rate, completely covering ponds and ditches and smothering river margins and channels.
"If they become established they have the potential to out-compete native vegetation and seriously compromise navigation and flood control.
"Unless we act now it could cost us tens of thousands of pounds, diverting money from other essential maintenance jobs."
The Avon Invasive Weed Forum is running an event on Tuesday to try to remove as much non-native invasive weed, starting in Manor Woods in Bishopsworth, Bristol.