Sonchus asper subsp. asper
Prickly sow thistle, Prickly Sow Thistle
Photo by Chez Brungraber
Family: Asteraceae · Type: Annual · Not Native
Sonchus asper subsp. asper (Prickly sow thistle) is a non-native California annual in the Asteraceae family, recognized by the rounded, coiled clasping lobes and soft-spine-tipped teeth.
Prickly sow thistle is a naturalized annual found throughout California in slightly moist disturbed sites and along streams at elevations below 1,900 meters. Flowering all year, this plant produces yellow flowers in heads 10 to 13 millimeters long with ligules about one-third the length of the flower tube. Growing 1 to 12 decimeters tall with mostly unbranched stems, it has a distinctive growth habit. Its leaves range from 6 to 30 centimeters long, with deeply toothed edges and soft spine-tipped margins, and lower leaves often have rounded, clasping bases that curve or coil. The fruit is straw-colored to red-brown, 2 to 3 millimeters long with pappus bristles about three times the fruit length.
Identification and appearance
Key characters: Co-occurs with 5 species; key feature is the rounded, coiled clasping lobes and soft-spine-tipped teeth
Habitat and range
Habitat: Common. Slightly moist disturbed sites, along streams
Elevation: < 1900 m
Outside California: North America, native to Europe
Bloom period
Sonchus asper subsp. asper blooms All year.
How to tell it apart
vs Taraxacum: Taraxacum has all basal leaves on leafless stalks, Sonchus has tall leafy branching stems.; vs Lactuca: Check seeds - Sonchus has no beak, Lactuca seeds have distinct neck before bristles.; vs Helminthotheca: Helminthotheca has spiny-bristly outer phyllaries creating a prickly appearance, Sonchus phyllaries are smooth.; vs Cirsium: Cirsium has spiny flower heads and disk flowers only, Sonchus has smooth heads with ray flowers.; vs Senecio: Senecio has yellow disk and ray flowers, Sonchus has only yellow ray flowers.
Frequently asked questions
Is Sonchus asper subsp. asper native to California?
No. Sonchus asper subsp. asper is not native to California (recorded as not native).
When does Sonchus asper subsp. asper bloom?
Sonchus asper subsp. asper blooms All year.
What plant family does Sonchus asper subsp. asper belong to?
Sonchus asper subsp. asper is in the Asteraceae family, genus Sonchus.
What habitat does Sonchus asper subsp. asper grow in?
Sonchus asper subsp. asper grows in Common. Slightly moist disturbed sites, along streams.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.