Authors: Karan Rawlins, Hillery Reeves and Kaylee Tillery at the Center for Invasive Species & Ecosystem Health, University of Georgia
- Acacia auriculiformis is a fast-growing, crooked, gnarly tree in the family Fabaceae. It is an evergreen tree ranging from 65 ft. (20 m) tall. It has a compact spread and is often multi-stemmed. The gray-white bark often shows vertical fissures. It has no thorns. The roots normally spread only shallowly. The young growth is usually glaucous. The leaf litter of Acacia auriculiformis is thought to be allelopathic.
- The leaves are alternate, simple and reduced to phyllodes (flattened leaf stalks). These blade-like leaves are slightly curved and range from 5-8 in. (11-20 cm) long. Leaves have 3-7 main parallel veins and a marginal gland near the base. The leaf surfaces are dark green.
- The flowers are held in loose, yellow-orange spikes in the leaf axils or in clusters of spikes at stem tips. Acacia auriculiformis flowers are mimosa-like, with many free stamens.
- An Acacia auriculiformis tree can produce about 47,000 seeds a year. The fruits are flat, oblong pods. Pods become twisted as they mature and then split to reveal flat black seeds. The seeds are attached by orange, string like arils.
- Ecological Threat
- Acacia auriculiformis is now common in disturbed areas. It has also invaded pinelands, scrub, and hammocks. Significant populations have been discovered in the globally imperiled pine rocklands of Dade County (M. McMahon, Biological and Environmental Consulting, personal observations). Acacia auriculiformis can displace native vegetation and shade out native plants. It is adapted to nutrient-poor soils in humid tropics and is fire adapted.
Acacia auriculiformis has been planted widely in the Old World for pulp and fuelwood, particularly in India and Southeast Asia. In Florida, naturalized populations of Acacia auriculiformis have been reported in many counties.
Seeds of Acacia auriculiformis are dispersed by several bird species and each tree can produce as many as 47,000 seeds each year.
Acacia auriculiformis is hermaphroditic and pollinated by a wide range of insects which forage mainly on pollen.
Acacia auriculiformis is native to Australia, Indonesia, Papua New Guinea
Acacia auriculiformis has been introduced to Hawaii and Florida in the United States, Cambodia, Cameroon, China, Democratic Republic of Congo, India, Japan, Kenya, Malawi, Malaysia, Nigeria, Philippines, Tanzania, Thailand, Uganda, Zanzibar, Zimbabwe
- Girdle larger trees. Hand pull seedlings and small plants. There are normally only shallow roots to worry about. Be sure to remove all plant material and either burn or bag it depending on the regulations in your area. Remember to consider in your follow-up measures, that hand pulling causes soil disturbance which can lead to further invasion by invasive plants.
- No information available.
- Triclopyr herbicide mixed with an oil. Always follow all label directions.
- No significant biocontrol agent known, although there are insect pests known in its native range.
- Fire may enhance germination of Acacia auriculiformis. You should consider discontinueing planting this species outside its native range, especially in tropical areas. Plant native or non-invasive alternatives instead. Ask your local native plant society for further alternatives.
Identification and Biology of Nonnative Plants in Florida’s Natural Areas - Second Edition, by K.A. Langeland, et al. University of Florida-IFAS Pub SP 257. 2008 
Forest Starr, Kim Starr, and Lloyd Loope. United States Geological Survey--Biological Resources Division. 2003 
U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. J.A. Parrotta. 1997 
University of Florida IFAS Extension Center for Aquatic and Invasive Plants 
CABI Invasive Species Compendium 
Florida Exotic Pest Plant Council 
AgroForestryTree Database 
USDA NRCS PLANTS 
USDA ARS GRIN 
Images from Bugwood.org