Family: Simaroubaceae

Origin, Description & Uses
Soulamea amara, commonly known as bitter tree, is a small tree or shrub native to a broad region extending from Borneo through New Guinea and Melanesia to the western Pacific. It is typically found in tropical forests and coastal habitats, where it produces glossy evergreen foliage and clusters of small flowers followed by distinctive winged fruits. Throughout its native range, bitter tree has been used in traditional medicine, with extracts from its bark, leaves, and roots employed for a variety of cultural and medicinal purposes. It is also occasionally cultivated as an ornamental plant due to its attractive foliage and adaptability to tropical conditions.

Risks & Threats
Soulamea amara is considered a low-risk species for Hawaiʻi. Although it is well adapted to tropical environments, there is little evidence that it spreads aggressively outside cultivation or forms invasive populations. The species does not appear to possess the rapid growth, prolific seed production, or broad environmental tolerance commonly associated with invasive plants. As with any non-native species, responsible planting and monitoring are recommended, particularly near natural areas. However, current information suggests that bitter tree presents a relatively low risk to Hawaiʻi’s native ecosystems and can be considered a suitable choice where a non-invasive ornamental or culturally significant tropical tree is desired.

High Risk Traits:

• Thrives in tropical climates (could naturalize in similar climate of Hawaiian Islands)
  
• Viable seeds dispersed by water

Low Risk Traits:

• No negative impacts or history of invasiveness have been documented
  
• Unarmed (no spines, thorns or burrs)
  
• Medicinal value