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Home > Weeds > Sowthistle

Annual Sowthistle—Sonchus oleraceus

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

sowthistle plant sowthistle rosettle of leaves sowthistle flower sowthistle puffball of seeds
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. Stems grow from a rosette of deeply toothed leaves. Stem leaves are alternate and less deeply toothed. Leaves are bluish-green. 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. "Puffballs" look similar to dandelions.

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

It is the policy of the State of Maine to minimize reliance on pesticides. The Maine Department of Agriculture and the Maine IPM Council encourage everyone to practice integrated pest management and to use pesticides only as a last resort. The mention of pesticides in the fact sheets linked to these pages does not imply an endorsement of any product. Be sure that any product used is currently registered and follow all label directions.