Marsh Ragwort

Marsh Ragwort can be seen flowering in the marshier places and wet meadows on the Lizard from high summer to early autumn.
Photo: Steve Townsend

Scientific name: Senecio aquaticus

We are all familiar with Common Ragwort (Senecio jacobaea) growing along our hedgerows and roadsides, but there are other species of ragwort to be found in Britain. If you see a ragwort plant in a marshy area, damp meadow or shady riverbank, it may well be Marsh Ragwort. The main way to distinguish it from Common Ragwort is the achenes (the single-seeded fruits): these are all hairless in the former, whereas the disc-floret achenes of the latter are hairy. Marsh Ragwort flowers also tend to be a little larger (25 to 30 mm across, compared to 15 to 25 mm), and the stem leaves have large oval lobes, compared to the more divided form found in Common Ragwort.

Although not quite as toxic to livestock and horses as Common Ragwort, Marsh Ragwort is still harmful and needs to be managed in fields used for grazing.

It is common across the British Isles, but has experienced a significant decline in south-east England, probably due to loss of habitat from drainage and intensification of farming methods.

Did you know…?

…There are three subspecies of Marsh Ragwort. You are most likely to see the widespread S. aquaticus subsp. aquaticus, the most widely distributed.

…The toxicity of ragwort species is derived from alkaloids, which make the plant taste very bitter and lead to liver damage if ingested. This evolved in the genus as a natural defence mechanism against being eaten.

More information and references:

Rose, F. and O’Reilly, C., 2006. The Wild Flower Key, 2nd edition. Frederick Warne, London.

Stace, C., 2010. New Flora of the British Isles, 3rd edition. Cambridge University Press, Cambridge.

Published: October 2013
Author: Amanda Scott
Photos: Steve Townsend