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Class A Noxious Weed

Purple Starthistle
Centaurea calcitrapa
 

Purple Starthistle flower


Plant family: Compositae
Year listed:
Native to: Asia Minor from a region between the Black and Caspian seas.

Why is it a noxious weed?
It is an aggressive Centaurea that invades grasslands, that out competes native vegetation.

 

How would I identify it?

Leaves:

  • lower leaves deeply divided
  • upper leaves are narrow and undivided
  • covered with cobwebby hairs that sometimes become smooth at maturity
  • rosette leaves are deeply divided with a circle of spines in the center

Flowers:

  • lavender to deep purple flowers
  • spine-tipped bracts subtend the flower head

Stems:

  • stems are covered with cobwebby hairs that sometimes become smooth at maturity

How does it reproduce?
Purple starthistle reproduces by seed.

Where does it grow?
Purple starthistle occurs mainly in grasslands.

What is the distribution in Washington State?
 

 

  • Distribution map not available at this time.

How do I control it?

General control methods:

Cultural: Digging may be effective for small infestations.

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

Biological: None currently developed.

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

 

More Photos-Click photo to enlarge
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Purple thistle infestation with seed
Purple starthistle infestation with seedpod.

 Last updated September 10, 2008