Prickly sowthistle (Sonchus asper) foliage varies from the rosette to stem stage. Rosette foliage is deeply lobed, 6 to 8 inches long, and with variable blue to green color.

Rosette foliage margins are deeply lobed, almost all the way to the mid-rib. Margins are serrated but not spiny.

Compare the anterior lobes of annual sowthistle and prickly sowthistle below. This is the easiest way to distinguish the two plants. However, this characteristic is not usable when the plants are in the rosette stage.

Above are basal lobes of prickly sowthistle (S. asper). Note how they curl under and look like an ear.	Above are basal lobes of annual sowthistle (S. oleraceae). Note how they point back and do not curl under to the extent that S. asper does.

Foliage clasps the stem, and is arranged alternately along the stem.

Return to the Weed Species Page

Return to the Weed Management Homepage

Email comments to James Altland