Family: Myrtaceae

Origin, Description & Uses
Syzygium cordatum, commonly known as water berry or umdoni, is an evergreen tree native to eastern and southern Africa, ranging from Uganda to South Africa. It typically grows along rivers, wetlands, and other moist habitats, where it can reach heights of 30–50 feet (9–15 m) or more. The tree is valued for its attractive glossy foliage, showy clusters of white to pinkish flowers, and edible purple fruits that are enjoyed by people, birds, and other wildlife. Water berry is widely planted as an ornamental shade tree and is also used in traditional medicine, agroforestry, and habitat restoration projects within its native range.

Risks & Threats
Although Syzygium cordatum is not currently known to be naturalized in Hawaiʻi, it possesses traits that are cause for concern. The species produces abundant fleshy fruits that can be dispersed by birds and other animals, increasing its potential to spread beyond cultivation. Its ability to thrive in wet environments, tolerate periodic flooding, and establish in disturbed habitats may allow it to colonize sensitive riparian and wetland ecosystems if introduced to suitable areas. While there is currently insufficient evidence to determine its full invasive potential in Hawaiʻi, caution is recommended to ensure that it will not negatively impact native ecosystems. Ongoing evaluation and monitoring are needed to determine whether this species could become a problem under Hawaiʻi’s environmental conditions.

High Risk Traits:

• Within native range, elevation range exceeds 2000 m, demonstrating potential environmental versatility
  
• Thrives in tropical climates
  
• Naturalized in South Africa, outside native range
  
• Aggressive root system
  
• Other Syzygium species have become invasive
  
• Potential alternate host of Eucalyptus pathogens
  
• Forms pure stands in native range
  
• Reproduces by seeds
  
• Hybridizes with other Syzygium species
  
• Rapid growth rate (time to reproductive maturity unknown)
  
• Seeds dispersed by birds, mammals, intentionally by people and possibly by water
  
• Resistance to fire, and tolerant of pollarding

Low Risk Traits:

• No reports of detrimental impacts, but no evidence of widespread introduction outside native range
  
• Unarmed (no spines, thorns or burrs)
  
• Provides fodder for livestock and other animals
  
• Ornamental and medicinal uses, and edible fruit
  
• Requires constantly moist soil
  
• Not reported to spread vegetatively
  
• One-seeded fruit (limits reproductive output)
  
• Seeds lose viability rapidly