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Class B Noxious Weed

Yellow Starthistle
Centaurea solstitialis
 

Other common names: Yellow cockspur, St. Barnaby's thistle
 Plant family: Compositae
Year listed:
Native to: Mediterranean

Why is it a noxious weed?
Yellow starthistle spreads aggressively. Cattle feeding on yellow starthistle may be poorly nourished and can be damaged by the spiny heads.

Horses may be poisoned and develop "chewing disease" or E.N.E. (Equine nigropallidal encephalomalacia) if they ingest large quantities (86 - 200% body weight) over 1-2 months. The disease is characterized by acute inability to eat or drink and the horses may die from dehydration and starvation. Only horses are affected. Chemical substances in yellow starthistle are somehow altered in the processes of digestion and metabolism producing a toxin which causes death of nerve centers in the brain controlling normal eating and drinking mechanisms. There is no cure.

 

How would I identify it?
General Description: Yellow starthistle reaches 18 -36 inches high. Has a deep taproot.

Leaves:

  • alternate
  • bases extend downward producing a winged effect
  • dull green
  • covered with woolly hairs

Flowers:

  • yellow, thistle like
  • 3/8 -3/4 inch yellowish spines in star like arrangement at base of flower head

Stems:

  • dull green
  • covered with woolly hairs

Line drawings are taken from 1,000 Weeds of North America, copyright of XID Service, Inc and used with permission. Permission granted by the author.

How does it reproduce?
Yellow starthistle reproduces by seed.

Where does it grow?

Yellow starthistle is found in rangeland, edges of cropland, abandoned farmlands and pastures, roadsides, railways and recreational areas.

What is the distribution in Washington State?
 
  • Yellow starthistle infestations are concentrated in the Southeast corner but extend as far north
    as Stevens County.
  • If you think you may have seen this weed, please contact your county weed coordinator or us at noxiousweeds@agr.wa.gov.

 

  • Distribution map not available at this time.

How do I control it?

General control methods:  Good pasture management can help prevent or limit initial infestations.

Cultural: Proper grazing management, limit yellow starthistle invasions. Small infestations may be hand pulled.

Herbicide: Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator.

Mechanical: Mechanical removal is not economically feasible for large, dense infestations.

Biological:

For more information
For more information, download our Written Findings.

 

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    Yellow starthistle flowers and stems. Yellow starthistle infestation.    

 Last updated July 02, 2008