Spiny Sowthistle (also known as Prickly Sow Thistle, Spiny-leaved Sow Thistle)
Kingdom: Plantae, Division: Tracheophyta, Class: Magnoliopsida, Order: Asterales, Family: Asteraceae, Genus: Sonchus, Species: Sonchus asper · Asteraceae (Daisy, Aster, or Sunflower family) · Simple, deeply lobed leaves, deciduous/annual
Species
Sonchus asper
Leaf Type
Simple, deeply lobed leaves, deciduous/annual
Family
Asteraceae (Daisy, Aster, or Sunflower family)
Shape
Lanceolate to oblong in outline, deeply pinnately lobed with rounded auricles (ear-like lobes) clasping the stem
Size
Approximately 4 to 10 inches long and 1 to 3 inches wide, which is typical for mature basal and lower stem leaves of this species
Margin
Irregularly dentate to spinose-serrate with prickly, sharp-toothed margins
Arrangement
Alternate along the stem, often forming a basal rosette in the early growth stages
Rarity
Very Common, frequently treated as a persistent garden weed
Color & Pattern
Vibrant medium to bright green on the upper surface, paler green underneath, glabrous (hairless) and sometimes slightly glaucous with a smooth appearance
Venation Pattern
Pinnate venation with a prominent whitish or pale green midrib branching out to secondary veins
Texture & Surface
Smooth, somewhat fleshy or succulent texture with prickly margins; generally hairless surfaces
Description
Sonchus asper is an annual or winter annual herb growing from a taproot, reaching heights of 30 to 150 cm. It produces hollow, upright stems that exude a milky white sap when broken. The flower heads are yellow, dandelion-like composites clustered at the top of the stems, later producing small achenes with a tuft of white hairs for wind dispersal.
Key Features
Distinguished by its prickly, crinkly, deeply lobed leaves that feature rounded auricles clasping the stem tightly, combined with the presence of milky sap and yellow composite flower heads
Habitat
Disturbed sites, gardens, lawns, agricultural fields, waste areas, roadsides, and urban crevices with full sun to partial shade and varied soil types
Geographic Range
Native to Europe, North Africa, and western Asia, but currently widespread as an introduced and naturalized weed across North America, Australia, New Zealand, and temperate regions globally
Condition Notes
The specimen appears healthy, vibrant green, actively growing in a narrow mulch bed beside a concrete step, exhibiting no obvious signs of severe disease or pest damage
Interesting Facts
Despite being considered a noxious weed by many gardeners, the young leaves are entirely edible and nutritious, containing high levels of vitamins and minerals. The seeds are readily eaten by various birds.
Medicinal & Uses
Historically used in folk medicine as a diuretic, tonic, and sedative. Young leaves can be consumed raw in salads or cooked like spinach once the prickly margins are removed or softened by cooking
Ecological Role
Provides early-season nectar and pollen for various pollinators such as bees and syrphid flies, while seeds serve as an important food source for finches and other small birds
Similar Species
Common Sowthistle (Sonchus oleraceus), which has less prickly, softer margins and different auricle shapes; and Dandelions (Taraxacum officinale), which lack leafy stems and have basal-only leaves without prickly stem-clasping lobes
Foraging Tips
Look for rosettes and upright stems in disturbed soils, along building edges, and in gardens during spring and summer. Wear gloves when harvesting to avoid the prickly spines on the leaf edges
Toxicity Warning
Non-toxic. Safe for human consumption and generally safe for livestock, though excessive ingestion of nitrate-accumulating weeds from contaminated soils can occasionally cause issues