Family: Fabaceae

Acacia retinodes, commonly known as water wattle or swamp wattle, is a fast-growing tree or large shrub native to southeastern Australia. It is well known for its attractive, feathery foliage and bright yellow, ball-shaped flowers that can appear throughout the year, making it a popular choice for ornamental planting. This species tolerates a wide range of soil types, grows quickly, and can adapt to both wet and dry conditions. In its native range, it is valued for erosion control, landscaping, and occasional use in windbreaks and shelterbelts.

Outside its natural range, however, Acacia retinodes poses risks as a potentially invasive species. Like many Australian wattles, it produces large numbers of long-lived seeds that are easily spread and form dense thickets, outcompeting native vegetation. Its ability to thrive in disturbed areas, coupled with tolerance to drought and flooding, increases its invasive potential in island ecosystems such as Hawaii and across the Pacific. Careful management and evaluation are needed before planting this species in sensitive environments.

High Risk Traits:

• Naturalized beyond native range: Reported in California and Hawaii.
  
• Potential Environmental weed: Considered invasive and locally abundant in some areas (e.g., Marin Islands National Wildlife Refuge, California).
  
• Forms dense thickets: Potential to outcompete native vegetation (evidence uncertain but plausible).
  
• Nitrogen-fixing: May alter soil chemistry and favor invasive spread.
  
• Produces viable seed: Capable of self-seeding and forming persistent seed banks (>1 year).
  
• Dispersal by animals: Seeds spread by birds and ants.
  
• Tolerates a wide range of soils: Grows in alkaline, saline, and disturbed soils.
  
• Fire-adapted: Benefits from mutilation/fire and may increase fire risk in ecosystems.

Low Risk Traits:

• No spines/thorns: Lacks physical deterrents to human or animal contact.
  
• No evidence of toxicity: Not reported to be toxic to humans or animals.
  
• Not shade-tolerant: Requires open, sunny habitats.
  
• Not aquatic or grass-like: Poses no risk to wetlands or grasslands.
  
• No evidence of allelopathy: Unlikely to chemically inhibit other plants.
  
• Moderate seed production: Not classified as prolific.