An annual of shallow water or wet, disturbed, nutrient-rich mud, especially at the edges of ponds, ditches, streams or rivers which are poached by drinking livestock. It is salt-tolerant and frequent on grazed estuarine marshes. Its seeds are long-lived and plants can re-appear following disturbance after many years of absence. Lowland.
The distribution of R. sceleratus is stable, although the species is now better recorded than it was in the 1962 Atlas, especially in Scotland and Ireland.
Circumpolar Boreo-temperate element, with a disjunct distribution; widely naturalised outside its native range.