A rhizomatous perennial, rarely annual, herb of arable fields, woodland rides, marshy pastures and waste places; overlapping in habitat with M. aquatica but typically replacing it in drier habitats or where water levels fluctuate markedly. 0?390 m (Drumore Loch, E. Perth).
M. arvensis was mapped as `all records` in the 1962 Atlas. Analysis of the database reveals that a substantial decline has occurred since 1950. It has declined as a weed of cultivated land, and this may partly account for the significant loss from the English Midlands northwards. Some early records may refer to M. x verticillata.
Circumpolar Boreo-temperate element; widely naturalised outside its native range.