Also called Centaurea maculosa.

Part of genus Centaurea in ✽ aster / ✽ daisy / 🌻︎ sunflower  family Asteraceae.

Native to northern 🇮🇹 Italy (Centaurea stoebe) and eastern 🇪🇺 Europe (Centaurea maculosa).   🗺 Map by county (🇺🇸 USA-48) (color key).   Invasive > learn+quiz Invasive > 🌐︎ various (tetraploid form) Invasive > 🇨🇦 🇺🇸 Canada+USA Invasive > report it! Invasive > 🇺🇸 USA Invasive > 🇺🇸 USA (subspecies micranthos) Invasive > Michigan Invasive > Michigan  Adobe Acrobat Reader file (page 77) seeds prohibited in Michigan  Adobe Acrobat Reader file (page 2)   Inv. trading card  Adobe Acrobat Reader file

🚼︎ For kids!  This plant described in a 🇺🇸 USDA Forest Service coloring noxious weeds page.

Uses by native peoples
(Ethnobotany database)
  On No-Planting List by Seneca Nation of Indians SNI.  Adobe Acrobat Reader file (page 60)

In areas where spotted knapweed is invasive, spotted knapweed roots produce an allelopathic chemical that stunts the growth of plants around them not already adapted to this attack.

Spotted knapweed produces large amounts of nectar during a short season.  Thus, this plant is sometimes promoted by migratory beekeepers (the 👥︎ keepers migrate seasonally, with the 🐝︎ bees being along for the ride) who are off-contract during that short spotted knapweed season.  Some then market their honey as being from "star thistle".

If you wish to discourage this process, please don't buy honey marked "star thistle" in areas where it may be sourced from invasive spotted knapweed. [1]

Learn more about spotted knapweed Centaurea stoebe

Management and Control (Wisconsin)  Adobe Acrobat Reader file Best Control Practices BCP (Ontario)  Adobe Acrobat Reader file treatment details (Michigan)  Adobe Acrobat Reader file (page 133) Control (Maryland)  Adobe Acrobat Reader file (page 9)
Biology and Biological Control  Adobe Acrobat Reader file Biological Control in Eastern USA  Adobe Acrobat Reader file (page 177)   I have also heard of controlling this plant using ⚶🐐︎ prescribed browsing / goatscaping.

🔍︎ 🔍︎ images Discover Life Encyclopedia of Life Michigan Flora Minnesota Wildflowers Missouri Plants Flora of North America USDA PLANTS db USFS Wikipedia