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Malta Starthistle


Centaurea Melitensis - Asteraceae Family


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  • Flowers: The flowers are yellow, span up to 1.5 inches, and are surrounded by a ring of sharp tan spines.
  • Seeds:  Seeds are tan with gray stripes. They are covered with fine hairs and have hooks to encourage spread by contact with other animals. Seeds can survive for up to 3 years in the soil.
  • Leaves: The leaves are alternate and narrowly oblong with smooth, toothed margins. They can be covered with stiff, thick hairs and resinous dots.
  • Flowering Time:  Malta Starthistle flowers from May through September.
  • Life cycle:  Malta Starthistle sprouts in late fall, remains a basal rosette through the winter, and in the spring grows 1-2 foot stems lined with spiny thorns. It flowers through the summer, producing seed in the fall.  


  • Malta Starthistle produces vigorous early growth and large mats that quickly displace other native species. 
  • Due to its spiny thorns, Malta Starthistle can reduce an area’s potential for recreation.
  • Malta Starthistle has been implicated in the emergence of chewing disease, a neurological disease in horses.


Most effective control methods

  • Small infestations of Malta Starthistle can be effectively controlled by manually pulling and disposing in the trash prior to seed production.
  • Biological control is largely ineffective. It is a poor grazing plant due to its thorns and toxicity. Animals avoid it if possible.
  • When applied just before flower production, chemical control can be effective in controlling Malta Starthistle populations.

Large Images


John M. Randall, The Nature Conservancy,

Malta starthistle: flower 



Joseph M. DiTomaso, University of California - Davis,

Malta starthistle: rosette



Krzysztof Ziarnek, Kenraiz via Wikimedia

Malta starthistle: flower



Forest and Kim Starr, Starr Environmental,

Malta starthistle: infestation



Javier Martin via wikimedia

Malta starthistle: foliage



John M. Randall, The Nature Conservancy,

Malta starthistle: flowers



D. Walters and C. Southwick, Table Grape Weed Disseminule ID, USDA APHIS PPQ,

Malta starthistle: seeds



Forest and Kim Starr, Starr Environmental,

Malta starthistle: infestation


  • Malta Starthistle Fact Sheet

  • References

    Bowman, G. (2016, May). Malta Starthistle, Maltese Starthistle (Centaurea Melitensis) [PDF file]. Retrieved from View PDF

    California Invasive Plant Council. IPCW plant report: Centaurea melitensis. Retrieved from

    DiTomaso, J.M., G.B. Kyser et al. (2013). Weed Control in Natural Areas in the Western United States [PDF file]. Weed Research and Information Center, University of California. Retrieved from View PDF

    Donaldson, S., & Rafferty, D. (2011, April 19). Identification and management of Malta starthistle (centaurea melitensis L.) [PDF file]. Retrieved from View PDF

    United States Department of Agriculture. (2015, February). Field guide for managing Malta starthistle in the southwest [PDF file]. Retrieved from View PDF

    Washington State Noxious Weed Control Board. Malta starthistle. Retrieved from