Yellow Starthistle
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Yellow Starthistle
Asteraceae (Sunflower Family)
Class A Weed
Yellow Starthistle Management
Description: Yellow starthistle is an annual, germinating either in the fall or spring that grows 2 to 3 feet tall. Deeply lobed basal leaves form a rosette, while stem leaves are linear or tapered at both ends. Stem leaves attach directly to the stem. An extension, of the leaf runs down the stem, giving it a winged appearance. Flower heads are made up of yellow flowers. The flower heads have bracts with a stiff, sharp, 0.75-inch thorn. Round in cross section, the long spine has one or more shorter lateral spine, at its base. Seed produced from ray flower, are dark-colored and lack bristles, while seed from disk flowers are lighter colored and have a tuft of white bristles.
Origin:Europe
Key Characteristics:
- Yellow flower
- 0.75-inch spine
Distribution: This weed is a serious problem in California and Idaho. In New Mexico, it has been found in isolated small populations and only a couple of major populations. Yellow starthistle is responsible for chewing disease in horses.
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