Family: Fabaceae

Acacia parramattensis, commonly known as Parramatta green wattle, is a fast-growing tree native to eastern Australia. It typically grows between 5–15 meters tall and is recognized for its feathery, bright green foliage and pale-yellow, ball-shaped flowers that bloom in summer. This species is often found in woodlands, open forests, and along waterways, where it plays a role in stabilizing soils and providing habitat for wildlife. Like many wattles, it is capable of fixing nitrogen, which improves soil fertility and supports surrounding plant growth.

Outside its native range, however, Acacia parramattensis has the potential to spread aggressively. It produces large numbers of seeds that remain viable in the soil for many years, enabling it to establish dense stands and outcompete native plants. Its rapid growth and ability to tolerate a wide range of conditions make it useful for reforestation and erosion control, but these same traits also increase its risk of becoming invasive in non-native regions. Care should be taken when planting this species in areas where it may escape cultivation. Acacia parramattensis has become naturalized on two of the main Hawaiian Islands: O‘ahu (notably Tantalus) and Moloka‘I (specifically the Kamakou Preserve).

High Risk Traits:

• Naturalized beyond native range: Known to be naturalized in Hawaii (Oahu and Molokai).
  
• Host for recognized pests and pathogens: Susceptible to the fungus Uromycladium notabile, which is economically significant.
  
• Bird-dispersed seeds: Seeds are dispersed by birds, which can facilitate spread to new areas.
  
• Tolerates fire: Can regenerate after low-intensity fires, potentially increasing its persistence in fire-prone ecosystems.
  
• Nitrogen-fixing: May alter soil chemistry and outcompete native vegetation.
  
• Fast-growing: Can reach maturity quickly, enhancing its ability to colonize disturbed areas.

Low Risk Traits:

• No spines, thorns, or burrs: Lacks physical deterrents that could harm animals or humans.
  
• Not toxic: No evidence of toxicity to humans or animals.
  
• Not shade-tolerant: Prefers open, sunny habitats, limiting its ability to invade dense forests.
  
• No vegetative spread: Reproduces primarily by seed, reducing its capacity for rapid clonal expansion.
  
• Not adapted for wind or water dispersal: Seeds lack adaptations for long-distance dispersal by wind or water.
  
• Not unpalatable to grazing animals: No evidence suggests it is avoided by herbivores, which may help control its spread.