Acacia auriculiformis aka Darwin Black Wattle

Acacia auriculiformis is an evergreen tree in the pea family. Common names include earleaf acacia and earpod wattle. Its native range spans southeast Maluku, New Guinea, and northern Australia. It grows beside rivers and creeks, and on swamp edges. It also occurs in grasslands, woodlands, and monsoon forests. The species has a Least Concern conservation rating.

In Florida gardens, trees reach 35–40 feet (10.7–12.2 metres) tall. Their crowns spread 25–35 feet (7.6–10.7 metres) wide. Other sources describe taller trees, reaching 82 feet (25 metres). Native trees can reach about 100 feet (30.5 metres). The trunk may twist beneath a rounded, uneven crown. Branches droop, and the crown gives open shade. Growth is fast, with reported gains of 6–8 feet (1.8–2.4 metres) yearly. Thin young twigs are green and lack thorns. Bark darkens with age and develops deep cracks.

The green foliage stays on the tree through the year. Mature trees bear phyllodes rather than true leaf blades. These flattened leaf stalks curve like a sickle. They feel leathery and have several lengthwise veins. They measure about 0.3–0.7 feet (0.1–0.2 metres) long. Bright yellow flowers form short spikes from spring through fall. The blooms have a scent, and insects pollinate them. Hard, flat pods change from green to brown. They twist as they ripen, giving an ear-like shape. Split pods expose black seeds held by orange threads. Fallen foliage and pods can create litter.

Grow this tree in full sun, not shade. It tolerates sand, loam, clay, and soils low in nutrients. It accepts acid and alkaline soils, with moderate salt tolerance. It prefers good drainage but withstands brief flooding. It also tolerates drought well. UF/IFAS lists USDA zones 10A–11; PFAF describes it as frost tender. Brittle wood and weak branch joints make wind damage a concern. Pruning helps build stronger branch structure. Serious pests and diseases are uncommon, though anthracnose sometimes affects foliage.

People grow this tree for shade, fuel, and paper pulp. Its roots help hold soil on worn or mined land. It can fix nitrogen and grow on poor sites. Yet seeds can sprout beyond planted areas. It has escaped in south Florida and become locally invasive. UF/IFAS does not recommend planting it. PFAF records edible gum and oil from the seeds. It reports no known hazards, but this does not establish safety for every use.