The Himalayan balsam has pink flowers and resembles the sweet pea
Nature lovers are being asked to track down an alien plant threatening to dominate Norfolk's river banks.
Despite resembling a sweet pea, the Himalayan balsam is a rampant weed, producing 700 seeds per plant.
"It'd be a shame for all the native vegetation to be swamped out by the Himalayan balsam," said the Broad's Authority's Mike Sutton-Croft.
The Himalayan balsam can be found throughout Norfolk including on the rivers Wensum and Bure.
It is by no means the only non-native species of plant in Norfolk.
"I think there's been something in the region of 3,000 introduced species into the UK," said Mr Sutton-Croft.
"Of those, only a very small percentage are what we call invasive meaning that they really cause problems for our native wildlife," he added.
Once the species are introduced into a new environment they are removed from the insects and diseases in their native habitat which help keep them under control.
The rivers in Norfolk also aid the Himalayan balsam as the plant can propel its seeds up to five meters throwing them into the water where they are washed further down-stream.
The Broads Authority are now looking for help in keeping the weed under control by asking people to report sightings of it.
They are organising a Weekend of Action from Saturday, 17 to Sunday, 18 July 2010, during which volunteers will be asked to pinpoint on a map where the weed is located along the River Bure.
"This is meant to be a fun weekend and you can do as much or as little as you like," said Beth Williams, Broads Authority conservation officer.
"If you happen to be walking your dog on a certain route we'd be grateful if you would check it out for balsam.
"If you spot a plant at the bottom of your garden just let us know, every single plant we find will help."