Family: Proteaceae

Origin, Description & Uses
Macadamia integrifolia (macadamia) is a tree native to southeastern Queensland and northeastern New South Wales in Australia. It is a medium-sized evergreen tree known for its attractive glossy leaves, fragrant flowers, and its highly valued edible nuts. Macadamia has become an important agricultural crop worldwide, especially in tropical and subtropical regions, including Hawaiʻi, where it is widely cultivated in orchards and home gardens for commercial nut production, culinary uses, and as a shade or ornamental tree in landscapes.

Risks & Threats
In Hawaiʻi, macadamia is considered low risk. It is naturalized on Molokaʻi and has the potential to naturalize on Oʻahu, typically spreading from planted trees through fallen nuts that can germinate under favorable conditions. However, it does not show aggressive invasive behavior and is generally slow to spread beyond cultivation areas. While volunteer seedlings may occasionally establish, it is not known to significantly disrupt native ecosystems. As with any non-native species, it should still be monitored in natural areas, but it is not currently considered a major ecological threat in the Hawaiian Islands.

High Risk Traits:

• Naturalized or native in tropical/subtropical climates
  
• Widely introduced outside its native range
  
• Tolerates a wide range of soil conditions
  
• Produces viable seed
  
• Hybridizes naturally with other Macadamia species
  
• Self-compatible (can self-fertilize)
  
• Dispersed intentionally by people
  
• Dispersed by water
  
• Dispersed by animals (rodents)

Low Risk Traits:

• No evidence of weediness
  
• No spines, thorns, or burrs
  
• Poor shade tolerance (requires full sun)
  
• Does not reproduce by vegetative fragmentation
  
• Long time to generative maturity (4+ years)
  
• Propagules not dispersed unintentionally, as produce contaminant, by wind, or by birds
  
• Short-lived seed bank (3–6 months)
  
• Highly susceptible to fire damage