Family: Rutaceae

Calodendrum capense, commonly known as the Cape Chestnut, is a beautiful flowering tree native to southern and eastern Africa, including Kenya, Tanzania, South Africa, and Swaziland. It grows in a range of habitats, from coastal forests to mountain woodlands. The tree is prized for its stunning, pinkish-white flower clusters and attractive, warty seed capsules, reaching up to 20 meters in height. Due to its ornamental value, it has been intentionally introduced to other regions with warm climates, including Hawaii and Australia, where it is sometimes planted as a landscape or street tree.

Cape Chestnut poses a low overall risk of becoming invasive. Its most significant risk factors are its ability to thrive in tropical and subtropical climates and its capacity for animal-assisted seed dispersal, as birds and mammals eat and spread its seeds. However, it is not reported to be weedy or invasive anywhere in the world. The tree does not spread aggressively, form dense thickets, or reproduce vegetatively. For gardeners and landscapers in Hawaii, this means the Cape Chestnut is generally a safe ornamental choice with a low likelihood of escaping cultivation, but it should still be planted and monitored responsibly.

High Risk Traits:

• Broad climate suitability (tropical/subtropical)
  
• Animal-dispersed (birds, mammals)
  
• Seeds survive gut passage
  
• Produces viable seeds (high germination)
  
• Tolerates varied soils
  
• Potential pest host (Asian Citrus Psyllid)

Low Risk Traits:

• Not reported as a weed
  
• No congeneric weeds
  
• Not spiny or thorny
  
• Not toxic to animals/humans
  
• Not self-compatible or apomictic
  
• Not dispersed unintentionally/as a contaminant
  
• Not wind- or water-dispersed
  
• No prolific seed production
  
• No persistent seed bank
  
• Not tolerant of mutilation/fire
  
• Not shade-tolerant
  
• No dense thickets