Family: Myrtaceae

Corymbia ficifolia (red-flowering gum, scarlet-flowering gum, red-flower gum) is a small to medium-sized evergreen tree native to southwestern Australia. It is best known for its showy clusters of bright red to orange flowers, which appear in summer and are highly attractive to birds and pollinators. The tree has glossy green leaves, a rounded canopy, and rough, fibrous bark. In Hawaiʻi, red-flowering gum is widely planted as an ornamental street and landscape tree because of its vibrant blooms, drought tolerance once established, and relatively compact size compared to other eucalypts.

In Hawaiʻi, Corymbia ficifolia is considered naturalized on Kauaʻi, Maui, and Hawaiʻi Island, meaning it can persist outside of cultivation in some areas. However, it is still currently rated Low Risk, as it has not shown aggressive spread or significant ecological impacts to date. While continued monitoring is appropriate—particularly given its ability to reproduce by seed—the species does not currently pose a major threat to native ecosystems. As with all non-native plants, thoughtful placement and management are encouraged, and landowners may also consider native or low-risk alternatives to further support Hawaiʻi’s unique environment.

High Risk Traits:

• Grows and naturalized in regions with subtropical climates
  
• Naturalized on Kauai, Oahu, Maui and Hawaii (Hawaiian Islands), as well as in New Zealand, South Africa
  
• Other Corymbia species are invasive
  
• Unpalatable to grazing animals
  
• Tolerates many soil types
  
• Reproduces by seeds
  
• Hybridizes naturally
  
• Seeds dispersed by wind, possibly water and intentionally by people
  
• Able to coppice and resprout after cutting

Low Risk Traits:

• No reports of negative impacts (other than possible landscape maintenance issues)
  
• Unarmed (no spines, thorns, or burrs)
  
• Optimal growth in full sun
  
• Ornamental
  
• Not reported to spread vegetatively
  
• Outcrossing in nature
  
• Seeds non-dormant, unlikely to form a persistent seed bank
  
• Herbicides provide effective control of Corymbia species