Acacia melanoxylon aka Australian Blackwood

Acacia melanoxylon, known as blackwood, is an evergreen in the pea family, Fabaceae. It comes from eastern and southeastern Australia, including Tasmania. It grows in wet forests, often beneath eucalypts. Its habitats include river forests and sites reaching into the mountains. The species varies from a shrub to a large tree.

In gardens, expect a height of 26–39 feet (8–12 metres). Its spread reaches 13–26 feet (4–8 metres). Larger trees can reach 148 feet (45 metres), well beyond the garden range. Growth is fast, and garden trees reach maturity within 10–20 years. The crown can spread or form a dense pyramid. Grey bark has dark cracks. The leathery, grey-green foliage varies in shape. Young plants bear fern-like leaves. Mature plants mostly carry phyllodes: flattened leaf stalks that serve as leaves. These are longer than wide and curve slightly.

Small, fluffy flowers appear in spring, ranging from white to pale yellow. Bees visit the blooms. The flowers have a strong scent and contain much pollen. Brown seed pods may follow the flowers. These twist like ribbons and reach about 0.33 feet (0.1 metres) long. PFAF records cooked flowers as food, including use in fritters. It lists no known hazards, but this does not establish safety for pets. The same source records a medicinal use for rheumatic pain.

Plant blackwood in full sun with shelter from harsh weather. It needs well-drained soil with an acid or neutral pH. Sandy soil and loam both suit it. It tolerates drought, though its native habitats include wet forests. RHS rates it H3, suited to mild and coastal UK sites. PFAF lists USDA zones 9–11. Colder sites need winter protection or cultivation under glass. Under glass, use full light and suitable peat-free or loam-based compost. Avoid hard pruning, which the tree resents. Propagate it from seed or semi-ripe cuttings.

Blackwood suits sheltered courtyards, city gardens and gravel gardens in mild areas. Growers also use it to restore woodland and hold soil. Its roots help limit erosion, and the plant fixes nitrogen. Its hard, dark timber takes a fine polish for furniture. Flowers yield yellow dye; pods yield green dye. The bark supplies tannin. PFAF flags weed potential, so spread needs attention. Possible pests include glasshouse red spider mite, fluted scale and mealybugs. Honey fungus may also affect it.