Family: Myrtaceae

Origin, Description & Uses
Metrosideros collina is native to the south-central Pacific region, where it occurs across island groups such as French Polynesia and nearby Pacific islands. It is a member of the ʻōhiʻa family (Myrtaceae) and typically grows as a small tree or shrub with attractive clusters of bright, brush-like flowers in shades of red, orange, or yellow. In its native range, it is valued for ornamental planting, habitat enhancement, and cultural uses, including traditional wood use and incorporation into local landscapes and gardens.

Risks & Threats
Although Metrosideros collina is not known to be naturalized in Hawaiʻi, it does possess traits that are cause for concern, including adaptability to a range of environments and the ability to produce abundant seeds that could aid in spread. Members of this genus can be ecologically competitive in suitable conditions, so its behavior outside its native range should be carefully considered. Caution is recommended to ensure that it will not negatively impact Hawaiʻi’s ecosystems, and ongoing evaluation is needed to determine whether it could establish and affect native plant communities in the future.

High Risk Traits:

• Self-compatible (high seed production)
  
• Produces viable, prolific seeds
  
• Wind-dispersed (very light seeds)
  
• Water-dispersed (seeds tolerate seawater)
  
• Intentionally dispersed by people
  
• Suited to tropical/subtropical climates
  
• Congeneric weed (other Metrosideros species are weedy)

Low Risk Traits:

• Not naturalized
  
• Not a weed (garden, agricultural, or environmental)
  
• No spines, thorns, or burrs
  
• Not allelopathic, parasitic, or toxic
  
• No fire hazard
  
• Not shade tolerant
  
• Narrow soil tolerance
  
• No vegetative fragmentation
  
• Not bird-dispersed
  
• No known persistent seed bank
  
• Natural enemies present (e.g., rust fungus)