It is native to Europe and Asia, but is widely distributed elsewhere, including much of North America, as an introduced species and sometimes a noxious weed.
The plant is common and widespread in Britain, however is very rare in Jersey.
[4] The plant is usually found in damp or wet habitats, such as bogs, ponds, streams, ditches, fen and rivers.
[5] Whilst it favours wet ground, it can survive submerged in water, and often can form floating rafts.
[5] It is an erect to ascending plant of up to 70 cm, bearing small (8-12 mm) flowers pink in bud, becoming blue when fully open, with yellow centers and white honey guides.