Family: Costaceae

Costus spiralis, commonly known as spiral costus or spiral ginger, is a tropical plant native to Central and South America. This striking perennial grows from rhizomes and is admired for its spiraling stems and bright, tubular flowers, which range from red to orange and attract hummingbirds and butterflies. Its lush, green foliage and unique spiral growth habit make it a popular choice for ornamental gardens, landscaping, and tropical-themed plantings. In addition to its decorative appeal, spiral costus is sometimes used in traditional medicine in its native range, though its primary role in Hawai‘i is ornamental.

Currently, Costus spiralis is considered Low Risk in Hawai‘i. It is not known to aggressively spread or disrupt native ecosystems, making it a safe option for gardeners seeking a tropical accent plant. While it should always be monitored like any introduced species, there are no significant documented threats or ecological concerns associated with this species on the islands.

High Risk Traits:

• Thrives in tropical climates
  
• Other Costus species have naturalized and may be invasive
  
• Shade-tolerant
  
• Reproduces by seeds and vegetatively by rhizomes
  
• Self-compatible (but floral morphology prevents self-pollination)
  
• Bird-dispersed
  
• Lack of ecological information minimizes accuracy of risk prediction

Low Risk Traits:

• No evidence of naturalization or invasiveness outside native range
  
• Unarmed (no spines, thorns or burrs)
  
• Non-toxic
  
• Ornamental value
  
• Hummingbird-pollinated in native range (may limit seed set where hummingbirds are absent)
  
• Limited or lacking seed production may minimize longer distance dispersal