Family: Fabaceae

Acacia podalyriifolia, commonly known as Queensland silver wattle, is a small, fast-growing tree native to Australia. It is valued in horticulture for its silvery foliage and showy yellow flowers, which has led to widespread planting as an ornamental species. However, like many other Australian acacias, it produces large quantities of long-lived seeds that are easily spread by animals, water, and human activity. The species grows well in a wide range of soils and climates, tolerates drought, and forms dense thickets that can displace native plants. Its ability to fix nitrogen also gives it a competitive edge in low-nutrient environments.

In Hawaii and across the Pacific, Queensland silver wattle poses a significant invasion risk. If it becomes established in island ecosystems, it could crowd out native vegetation, alter soil chemistry, and contribute to wildfire risks by adding fast-burning biomass. Because Hawaii and many Pacific islands have unique and vulnerable ecosystems, the aggressive growth and reproductive capacity of A. podalyriifolia make it a high-risk species that should be carefully managed to prevent further spread.

High Risk Traits:

• Able to grow in temperate to subtropical climates
  
• Naturalizing outside native range in Australia
  
• Several Acacia species have become invasive
  
• Tolerates many soil types
  
• Forms pure stands and thickets in native range
  
• Nitrogen fixing tree; may modify soil nutrients
  
• Reproduces by seeds and vegetatively by root suckers
  
• Self-compatible (but requires pollinators for pollen transfer)
  
• Seeds dispersed by gravity, water, internally by animals and intentionally by people
  
• Seeds able to be stored for extended periods; May form a persistent seed bank
  
• Able to coppice and resprout after cutting, browsing and fire

Low Risk Traits:

• Unarmed (no spines, thorns, or burrs)
  
• Provides fodder for livestock
  
• Non-toxic
  
• Ornamental
  
• Slow growing (may take years before reaching reproductive maturity)
  
• Herbicides effectively control several other invasive Acacia species, and would presumably be effective if needed to control Acacia pendula