Information on Smooth Sowthistle

Common Name: Smooth Sowthistle
Scientific Name: Sonchus oleraceus
Irish Name: Bleachtán mín
Family Group: Asteraceae
Distribution: View Map (Courtesy of the BSBI)
Flowering Period


Click for list of all flowering by month
Smooth Sowthistle could sometimes be confused with:

Sowthistle, Perennial, Hawk's-beard, Beaked, Sowthistle, Prickly,

Sowthistles and other such 'Dandelion-like' flowers are difficult to identify.  Having said that, I'd like to present this wildflower with as much confidence as I can muster.  Smooth Sowthistle is a hairless, greyish annual or biennial which reaches about 80cm high.  Its pale yellow flowerheads are numerous (20-25mm across) and are borne in clusters on stalks, which, when broken exude a milky sap.  The individual flowers are comprised of strap-shaped ray florets, backed by a circle of closely overlapping bracts, and they bloom from May to November.  The leaves are not glossy, rather matt, have only softly spiny margins and they clasp the stem with arrow-shaped points, the lower leaves being pinnately lobed. This is a widespread native plant which belongs to the family Asteraceae 

My first record of this wildflower is at Dalkey, Co Dublin in 1980.  I photographed it in Gibletstown, Co Wexford in 2007. 

If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre

Sowthistle, Smooth
Sowthistle, Smooth