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University of Missouri

MU Weed Science

Annual Sowthistle

Sonchus oleraceus

Annual Sowthistle

Annual Sowthistle

Annual Sowthistle

Annual Sowthistle

Weed Description
An annual with bluish-green leaves and stems that secretes a milky sap when cut. Found throughout the United States.

Seedlings
Cotyledons egg-shaped and have petioles. Young leaves are alternate, egg-shaped, and form a rosette. Both young leaves and cotyledons have a whitish coating.

Leaves
Rosette leaves alternate, egg-shaped, with toothed margins. Stem leaves are alternate, without hairs, and have lobes that clasp the stem. Leaf margins are toothed and only slightly prickly.

Stems
Unbranched, 1-4 ft in height, and emit a milky sap when cut.

Flowers
Several occur in clusters at the end of the stems, pale yellow, 1/4 to 3/4 inch wide.

Roots
Taproot.

Trouble identifying a weed?

For additional assistance identifying weeds, contact Dr. Kevin Braldly, State Extension Weed Scientist (bradleyke@missouri.edu).

Affiliates

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Published by Division of Plant Science & Technology, 52 Agriculture Lab, Columbia, MO 65211