Wanted for: escaping from garden ponds and invading field ponds, reservoirs, gravel pits, streams, canals and ditches - drowning out our weedy, native waterweeds.
Originally from: lowland central South America; first found in Britain in 1960.
Latin name: Myriophyllum aquaticum
Distinguishing features: feathery, bright green waterweed, with some shoots emerging from the water. No flowers.
Super Invasive Powers: unstoppable - can even continue to grow when a pond dries out! Only female plants are found in the UK and so it spreads by vegetative means only (without flowers and seeds) - from stem fragments carried in water.
The following factsheet was written by the Centre for Ecology & Hydrology (CEH)