Family: Asteraceae

Cosmos atrosanguineus, commonly known as black cosmos or chocolate cosmos, is a perennial flowering plant native to Mexico. It is best known for its deep, velvety maroon to nearly black flowers and a distinctive chocolate-like fragrance, which makes it a favorite in ornamental gardens. Growing from tuberous roots, black cosmos typically reaches about 1–2 feet tall and produces daisy-like blooms on slender stems during the warmer months. It is widely cultivated for its unique color, pleasant scent, and value as a cut flower, as well as for attracting pollinators such as butterflies and bees.

At present, Cosmos atrosanguineus is not known to be invasive or naturalized in Hawaiʻi, and there is no evidence that it poses significant ecological risks. Because it is usually propagated vegetatively and has limited ability to spread on its own, the likelihood of it escaping cultivation is considered low. When grown responsibly in gardens or landscapes, black cosmos is generally regarded as a low-risk ornamental plant with minimal threat to native ecosystems.

High Risk Traits:

• Able to grow in tropical climates
  
• Other Cosmos species have become invasive
  
• Unpalatable to deer and rabbits
  
• Tolerates many soil types
  
• Tuberous roots (functional geophyte)

Low Risk Traits:

• No reports of invasiveness or naturalization
  
• Unarmed (no spines, thorns, or burrs)
  
• Non-toxic
  
• Ornamental
  
• Sterile (only found in cultivation)
  
• Self-compatible
  
• Not reported to spread vegetatively
  
• Lack of fertile achenes limits ability of plant to escape and spread outside cultivation