Information on Prickly Sowthistle

Common Name: Prickly Sowthistle
Scientific Name: Sonchus asper
Irish Name: Bleachtán colgach
Family Group: Asteraceae
Distribution: View Map (Courtesy of the BSBI)
Flowering Period


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

Sowthistle, Smooth, Sowthistle, Perennial,

On cultivated or waste ground, from May to October , this annual or biennial stands upright displaying heads of rich, Dandelion-like flowers.  The flowers (20-25mm across) are composed of yellow ray florets and are in clusters on stiff stems which, if broken, exude a white sap.  The leaves are bright shiny green above with jagged, spiny margins and they clasp the stems at their bases with rounded lobes, also prickly.  After the flowers have faded, clocks of seeds are formed.  This wildflower reaches up to about 1 metre, is a native plant and belongs to the family Asteraceae.

I first recorded this plant in Dalkey, Co Dublin in 1977 and 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, Prickly
Sowthistle, Prickly

The seeds of this plant are sought out and eaten by birds so helping propagation.  'Sonchus' -  the name of this genus -  is Latin for ''hollow'' which refers to the plant's hollow stems.