Family: Amaranthaceae

Gomphrena globosa (globe amaranth), also known as bachelor’s button or bozu, is a widely cultivated ornamental plant prized for its brightly colored, globe-shaped flower heads and resilience in tropical climates. Native to the Neotropics, this annual herb has become naturalized in parts of Hawaiʻi, especially on Oʻahu, Mauai and Kauaʻi, where it occasionally escapes cultivation. Though it thrives in hot, dry conditions and poor soils, it does not form dense thickets or spread aggressively. While globe amaranth is mildly toxic to livestock due to oxalates, it poses little environmental threat and is not known to displace native species. Although rated as a high risk species, it is only reported to be weedy in disturbed areas.

High Risk Traits:

• Thrives and can spread in regions with tropical climates
  
• Naturalized Oʻahu, Maui, and Kauaʻi (Hawaiian Islands) and potentially elsewhere
  
• A weed of disturbed areas
  
• Other Alternanthera species are weedy
  
• Reported to be moderately toxic to sheep, cattle, horses and donkeys
  
• Tolerates many soil types (not limited by substrate)
  
• Reproduces by seed
  
• Seeds dispersed by wind, potentially attached to animals, and through intentional cultivation
  
• Capable of prolific seed production

Low Risk Traits:

• Weediness only reported from disturbed habitats
  
• Unarmed (no spines, thorns, or burrs)
  
• Palatable to animals (despite reports of toxicity)
  
• Thrives in high light environments (dense shade may inhibit spread)