Family: Myrtaceae

Origin, Description & Uses
Sea apple (Syzygium grande) is a large evergreen tree native to parts of South and Southeast Asia, ranging from Assam and southern China through western Malesia. It is valued as an ornamental shade tree because of its dense canopy, attractive glossy leaves, showy white flowers with numerous stamens, and distinctive large fruits that turn pink to reddish-purple when mature. The species is commonly planted in tropical and subtropical landscapes, parks, coastal areas, and gardens, where it is appreciated for its aesthetic appeal, tolerance of coastal conditions, and ability to provide shade.

Risks & Threats
Syzygium grande is naturalized on Oʻahu and possesses traits that are cause for concern in Hawaiʻi. It produces abundant fruit that can be dispersed by birds and other animals, allowing seedlings to establish beyond cultivation. The species has the potential to spread into natural areas, where it may compete with native vegetation, alter forest structure, and contribute to the displacement of native species. Because tropical island ecosystems are particularly vulnerable to invasive plants, continued spread of sea apple could have detrimental ecological impacts. Since this species is already naturalized in Hawaiʻi, its use should be carefully managed and avoided near natural areas or in regions where it is not yet widely established. When selecting trees for landscaping, choosing a low-risk or native alternative is recommended whenever suitable options are available.

High Risk Traits:

• Thrives in tropical climates
  
• Naturalized on Oahu, Hawaiian Islands
  
• Other Syzygium and Eugenia species are invasive
  
• Shade-tolerant
  
• Tolerates many soil types
  
• Forming thickets where naturalized in Hawaiian Islands, and forms dominant cover in coastal forests within native range
  
• Reproduces by seeds
  
• Seeds dispersed by birds, other frugivorous animals, by water and intentionally by people
  
• Coppices when young; coppicing ability declines with age
  
• 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
  
• Fire-resistant; planted as a fire break
  
• Not reported to spread vegetatively
  
• Seeds recalcitrant, lose viability rapidly and will not form a persistent seed bank