Sonchus asper (L.) Hill
prickly sow-thistle (spiny sowthistle)
Asteraceae (Aster family)

Introduction to Vascular Plants


© Bryan Kelly-McArthur     (Photo ID #76927)


E-Flora BC Static Map

Distribution of Sonchus asper
Click here to view the full interactive map and legend

Species Information

Annual herb from a short taproot; stems erect, solitary, few-branched above, glabrous, hollow, exuding milky juice when broken, 0.1-1 m tall.
Basal leaves lacking; stem leaves alternate, prickly- margined, lowermost with stalks but not so clearly divided (as in S. oleraceus) into blade and stalk, more or less egg-shaped, uppermost deeply pinnately cut to egg-shaped and lobeless with rounded, clasping flanges at the base, 6-30 cm long, 1-15 cm wide.
Heads with strap-shaped flowers, several on sometimes glandular stalks in an open, flat-topped inflorescence, relatively small, commonly 1.5-2.5 cm wide in flower; involucres 9-14 mm tall; involucral bracts lanceolate, tapering to a slender tip at the apex, glabrous except for some spreading, gland-tipped hairs; ray flowers yellow.
Achenes 2.5-3 mm long, with 3 or rarely 4-5 conspicuous longitudinal ribs on each face, not wrinkled; pappus of white hairlike bristles.

SourceThe Illustrated Flora of British Columbia


If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.


Ecological Framework for Sonchus asper

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres)
410 204 1270
Slope Gradient (%)
14 0 70

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

223 45 350
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
4 1 6
Modal Nutrient Regime
# of field plots
 species was recorded in:
Modal BEC Zone Class

All BEC Zones (# of stations/zone) species was recorded in

BG(6), CWH(66), IDF(4), PP(8)

Habitat and Range

Mesic to dry roadsides, disturbed areas and gardens in the lowland, steppe and montane zones; frequent in all but N regions of BC; introduced from Europe.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Sonchus asper subsp. asper
Sonchus asper subsp. glaucescens (Jord.) J. Ball
Sonchus nymanii Tineo & Guss.