Family: Zingiberaceae

Alpinia purpurata, commonly known as red ginger, is a striking ornamental plant recognized for its tall, vibrant red flower bracts that are popular in tropical landscaping and floral arrangements. Native to the Indo-Pacific region, it thrives in warm, moist environments and has been widely cultivated across the Hawaiian Islands for its beauty and cultural significance. On Oʻahu and Hawaiʻi Island, it is only found in cultivation, where it is grown in gardens and as a commercial cut flower.

On other islands, however, Alpinia purpurata has shown the ability to escape cultivation. It is naturalized on Kauaʻi, Molokaʻi, and Maui, where it may spread into moist forests and disturbed areas. Once established, red ginger could outcompete other understory species and alter habitat structure. While admired for its ornamental value, its naturalization in certain areas of Hawaiʻi raises concerns about its long-term ecological impact.

High Risk Traits:

• High climate match for tropical/subtropical regions.
  
• Naturalized outside its native range (e.g., Hawaii, Fiji).
  
• Repeatedly introduced via the ornamental plant trade.
  
• Host for pests and pathogens (e.g., mealybugs, root rot).
  
• Tolerant of shade, enabling establishment in forests.
  
• Spreads vegetatively via resilient rhizomes.
  
• Tolerates being cut back, complicating control.

Low Risk Traits:

• Not documented as a significant agricultural or environmental weed.
  
• Lacks spines, thorns, or burrs.
  
• Not toxic to animals; has culinary/medicinal uses.
  
• Not a fire hazard due to moist habitat.
  
• Poor natural seed dispersal (no wind, animal attachment, or contaminant potential).
  
• Low seed production; rarely fruits in cultivation.