Annual Sowthistle—Sonchus oleraceus
An annual weed, common in vacant lots, roadsides, cultivated fields and gardens.
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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More Information
- Integrated Pest Management for Home Gardeners and Landscape Professionals: Weed Management in Landscapes (PDF) —University of California
- Weeds and Your Garden brochure (PDF) —New York State IPM Program and Cornell Cooperative Extension
- Weed Management in the Home Garden (PDF) —Iowa State University Extension
[Photos, left to right: Richard Old, XID Services, Inc., Bugwood.org; Robert Vidéki, Doronicum Kft., Bugwood.org; Steve Dewey, Utah State University, Bugwood.org; Chris Evans, River to River CWMA, Bugwood.org]