Acacia mearnsii aka Black Wattle

Acacia mearnsii, or black wattle, is in the pea family, Fabaceae. It comes from the southeast of Australia, including Tasmania. It grows beneath tall, open forests. It also grows along the edges of closed forests. It forms dense stands where plants return after land clearing. People grow it in warm regions for bark, wood, and shade.

This tree grows fast and stays green all year. It has no spines. Its crown is round and spreads out. It may have one trunk or branch near the ground. Garden accounts give heights around 33 feet (10 metres). Other sources give a usual range of 20–49 feet (6–15 metres). Rare trees reach 66–82 feet (20–25 metres). Its spread can reach about 26 feet (8 metres). The trunk is often straight, with rough, brown bark. Its dark green leaves divide into fine parts. They give the crown a feathery look.

Pale yellow flowers grow in round heads. These form large sprays with a scent. Reports place bloom time from early spring into late summer. Bees and other insects visit the flowers. The tree is self-fertile. This means it needs no other tree for pollination. Dark brown pods follow the blooms and bear fine hairs. The tree draws wildlife. The supplied accounts give no more detail on this.

Choose full sun and moist soil that drains well. Sandy and loamy soils suit it, including poor soils. It accepts acid to neutral soil, even strongly acid soil. It fixes nitrogen and can help improve worn-out ground. A mild climate suits it best. Extreme heat and cold limit growth. Frost and cold winds can harm growth and survival. Older trees may withstand light frost. Young plants need frost protection. PFAF lists USDA zones 8–11. Both care accounts stress that frost can harm it. The tree also needs shelter from wind.

Growers use black wattle for tannins, timber, fuel, and charcoal. Trees shade crops and give shelter. They also help stop soil loss on poor slopes. The leaves and other plant matter serve as green manure. Both plant-use sources warn that it may become a weed. This matters when choosing a planting site. PFAF lists seeds and gum as edible parts. People eat the gum or mix it into drinks. The bark is rich in tannins. It has traditional use as an astringent in medicine. PFAF reports no known hazards. This does not mean it is safe for pets or people.