Acacia dealbata
silver wattle
Overview
Acacia dealbata is a fast-growing evergreen tree in the legume family, reaching 50-100 feet (15-30 m) tall with an open, spreading crown and smooth grey-green bark that darkens and fissures with age. The bipinnate leaves are fern-like, 1.5-5 inches (4-12 cm) long, divided into many small leaflets coated in silvery-grey hairs that give the foliage a blue-grey cast. From late winter into spring the branches carry dense sprays of small, globular flower heads, each a ball of about 25-35 tiny golden-yellow flowers 0.2 inch (5-6 mm) across, releasing a sweet scent. Flat, blue-grey seed pods 1.5-4 inches (4-10 cm) long follow and ripen to brown. The tree fixes nitrogen through root nodules, grows rapidly, and is short-lived, often declining after 30-40 years. It suckers from the roots and self-sows heavily, and it is listed as an invasive weed in parts of Africa, Europe, and the Americas. Frost cuts back young growth, and the brittle wood breaks in storms. It grows in cool to warm temperate climates on a wide range of well-drained soils.
Native Range
Native to southeastern Australia, including Tasmania, New South Wales, and Victoria, where it grows in cool mountain forests and along watercourses. It has naturalised widely in southern Europe, Africa, India, and the Americas, where it is often treated as an invasive weed.Suggested Uses
Grown as a fast screen, windbreak, or specimen tree in frost-free temperate gardens, and cut as the florist mimosa for scented winter sprays. It suits large gardens and slopes for quick cover, though its suckering and seeding make it unsuitable near natural bushland.How to Identify
Appearance
Size & Dimensions
Height50' - 100'
Width/Spread20' - 40'
Bloom Information
Detailed Descriptions
Foliage Description
silvery blue-greyGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Performs in full sun on free-draining, slightly acidic to neutral soil at a pH from 5.0 to 7.0. Once established it tolerates drought and poor, sandy or gravelly ground, fixing its own nitrogen. Young plants are damaged by hard frost, and the species is hardy only to about 20-25 F (-4 to -7 C) in zones 9 to 11. Growth is fast but the wood is brittle and prone to wind and snow breakage. The tree suckers from roots and seeds prolifically, so it spreads beyond where it is planted. In containers it is short-lived and needs a deep, free-draining mix.Pruning
Light shaping after flowering keeps the crown open and removes storm-damaged limbs. Hard pruning into old wood often fails to resprout. Removing root suckers and seedlings checks unwanted spread.Container Growing
✓ Suitable for container growing
Minimum container size: 15 gallons