Family: Myrtaceae

Origin, Description & Uses:
Syzygium syzygioides is a tropical evergreen tree native to parts of South and Southeast Asia, ranging from Kerala and Arunachal Pradesh in India through western Malesia. A member of the myrtle family (Myrtaceae), it typically forms a medium-sized tree with a dense crown, glossy green leaves, small flowers, and fleshy fruits. The species is valued primarily as an ornamental tree for its attractive foliage and shade-producing canopy. Like other members of the genus Syzygium, it may also provide food and habitat for wildlife and can be used in landscape plantings, parks, and agroforestry systems.

Risks & Threats:
Syzygium syzygioides has become naturalized on Oʻahu and possesses traits that are cause for concern. Its fruits may be dispersed by birds and other animals, allowing seedlings to establish beyond cultivated areas. The species appears capable of growing in tropical environments similar to those found in Hawaiʻi, raising questions about its potential to spread into natural ecosystems. Although its current impacts are not fully understood, ongoing evaluation is needed to determine whether it could become more widespread or negatively affect native habitats. Because of these uncertainties, caution is recommended when planting this species, and monitoring is encouraged to ensure that it does not negatively impact Hawaiʻi’s unique ecosystems.

High Risk Traits:

• Elevation range exceeds 1000 m, demonstrating environmental versatility
  
• Thrives in tropical climates
  
• Naturalized on Oahu, Hawaiian Islands
  
• Other Syzygium and Eugenia species are invasive
  
• Shade-tolerant
  
• Reproduces by seeds
  
• Seeds dispersed by birds, other frugivorous animals, possibly by water and intentionally by people
  
• Gaps in biological and ecological information reduce accuracy of risk prediction

Low Risk Traits:

• No reports of negative impacts in native or introduced range
  
• Unarmed (no spines, thorns, or burrs)
  
• Non-toxic
  
• Not reported to spread vegetatively
  
• Seeds recalcitrant, lose viability rapidly and will not form a persistent seed bank