Sonchus asper

Weedy European plant with spiny leaves

Sonchus asper spiny sowthistle

Plant grows in the wild/spontaneously

This is a nonnative plant from Europe that usually grows as an unwelcome weed. There are several species of sowthistle in our state. The spiny sowthistle has very spiny, curved leaves and bases that envelope the stem with lobed 'ears' protruding on the other side. The leaves are up to ten inches long with prickly edges. The leaves are often deeply lobed. It is a member of the aster family and has small one-inch wide yellow flowers that somewhat resemble dandelions. The flowers grow in clusters at the ends of the stems. The fruit is seed-like with hair-like bristles to aid wind distribution. The stem is smooth, hollow, and contains milky sap. The related common sow-thistle (S. oleraceus) has leaves that are less curved and has pointed lobes where the leaves clasp the stem. Sonchus asper grows 1-5 feet tall, most along roadsides and in waste or disturbed places. It is present throughout North America except for the Arctic. It blooms almost continuously from June to October. It is also known by the common names sharp-fringed sow-thistle, prickly sow-thistle. This species is listed as a noxious weed in some states. Young leaves are edible as a potherb if the spines are trimmed off.

Contributed by: Mark Welchley

Grows in meadows, fields, and man-disturbed habitats.

Present throughout the state.

Range: Found throughout North America.

Wetland codes

Flowers May to October.

Sonchus asper spiny sowthistle

Plant grows in the wild/spontaneously
Sonchus asper gallery
Plant Life-Form
annual forb
Common Names
spiny sowthistle spiny thistle spinyleaf sowthistle sharp-fringed sowthistle