This vigorous perennial herb is found in wet places by streams, rivers and ponds, in damp meadows, marshy ground and open woodland. It spreads both by seed and vegetatively, rooting from the nodes in wet mud or gravel. Generally lowland, but upper altitudinal limit unknown.
M. guttatus is thought to have been introduced to cultivation in 1812. It soon became established in semi-natural habitats, being known in the wild by 1824. It continues to be a popular garden plant, but its distribution is probably stable. It has been much over-recorded for other taxa in the uplands.
Native of western N. America.
Count of 10km squares in Great Britain: 996
Count of 10km squares in Ireland: 44
Count of 10km squares in the Channel Isles: 4
PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.