University of Missouri Extension

IPM1007, Revised November 2009

Practical Weed Science for the Field Scout: Corn and Soybean

Sowthistle, spiny (Sonchus asper)

Winter annual broadleaf

Sowthistle, spinySowthistle, spiny
Sowthistle, spinyAn annual weed that may reach as much as 6 feet in height with bluish green leaves and stems that emit a milky sap when cut. Young leaves form a basal rosette. Leaves are generally hairless, egg shaped in outline with prickly margins. Leaves that occur on the flowering stem are alternate and have rounded lobes that clasp the stem. Leaves also emit a milky sap when broken. Yellow flowers occur in clusters at the ends of stems and range from 1/2 to 1 inch in diameter.

 

Wild thing
 

IPM1007 Practical Weed Science for the Field Scout: Corn and Soybean | University of Missouri Extension

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