Family: Solanaceae

Origin, Description & Uses
Solanum betaceum, commonly known as tree tomato or tamarillo, is a small, fast-growing shrub or tree native to tropical South America. It typically reaches 10–18 feet (3–5.5 m) in height and produces clusters of colorful egg-shaped fruits that may be red, orange, or yellow when ripe. Tamarillo is widely cultivated in subtropical and tropical regions for its edible fruit, which has a tangy, slightly sweet flavor and is used fresh or in juices, sauces, jams, desserts, and preserves. The plant is also valued as an ornamental due to its large leaves, attractive flowers, and colorful fruit display.

Risks & Threats
Although Solanum betaceum is not currently known to be naturalized in the Hawaiian Islands, it possesses several traits that warrant caution. The species produces abundant fruit containing numerous seeds that can be dispersed by birds and other animals, potentially allowing it to spread beyond cultivation. Tamarillo can establish in disturbed habitats and favorable climates, raising concerns about its ability to escape cultivation and compete with desirable vegetation. Because tropical islands are especially vulnerable to biological invasions, this species could detrimentally impact native ecosystems if it became widely established. For these reasons, Plant Pono recommends choosing a low-risk or native alternative when suitable options are available, particularly for landscaping and agroforestry projects near natural areas.

High Risk Traits:

• Naturalized in multiple countries (Australia, New Zealand, Taiwan)
  
• Listed as a weed/invader in New Zealand and South Africa
  
• Shade-tolerant, invades forest understories
  
• Self-fertile (single trees produce seeds)
  
• Bird- and bat-dispersed seeds
  
• Reaches reproductive maturity in 1–2 years
  
• Tolerates a wide range of soils
  
• Resprouts after pruning or damage
  
• Unripe fruit mildly toxic

Low Risk Traits:

• Limited to subtropical climates (intolerant of extreme heat or frost)
  
• Large fruits/seeds not dispersed accidentally (wind, water, or produce contaminant)
  
• No persistent soil seed bank (seeds viable <1 year in field conditions)