Annual Sowthistle—Sonchus oleraceus

An annual weed, common in vacant lots, roadsides, cultivated fields and gardens.

sowthistle plant
Stems grow 1 to 4 feet tall. Although leaves look prickly it does not hurt to touch them. Stems secrete a milky sap when cut.

sowthistle rosettle of leaves
Stems grow from a rosette of deeply toothed leaves. Stem leaves are alternate and less deeply toothed. Leaves are bluish-green.

sowthistle flower
Flowers form in clusters at the end of stems. Pale yellow ray flowers are ¼ to ¾ inch wide and bloom from June to October.

sowthistle puffball of seeds
"Puffballs" look similar to dandelions.

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More Information

[Photos, left to right: Richard Old, XID Services, Inc.,; Robert Vidéki, Doronicum Kft.,; Steve Dewey, Utah State University,; Chris Evans, River to River CWMA,]