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Acacia decurrens

Sydney green wattle

Fabaceae South-eastern Australia

Attracts Pollinators Drought Tolerant Fragrant (light)

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 9–11

Overview

Acacia decurrens is a fast-growing evergreen tree reaching 20-50 feet (6-15 m) tall, with a spreading crown and dark, finely fissured bark. Raised ridges (decurrent lines) run down the angular branchlets from the leaf bases. The leaves are bipinnate and feathery, 1.5-4.5 inches (4-11 cm) long, bright green, with 5-15 pairs of pinnae each carrying many narrow leaflets. From late winter into spring, the tree carries abundant globular flower heads about 0.2-0.3 inch (5-7 mm) across, bright yellow and lightly fragrant, grouped in long sprays. Flat, dark brown seed pods 2-4 inches (5-10 cm) long follow, slightly constricted between the seeds. Growth is rapid, with young trees gaining 3-6 feet (0.9-1.8 m) per year, but the species is short-lived, typically 15-30 years. As a legume it fixes nitrogen and colonizes disturbed and cleared ground, where it can spread beyond plantings.

Native Range

Native to south-eastern Australia in New South Wales and the Australian Capital Territory, on the tablelands and coast. Grows in open forest and woodland on clay and loam soils, and readily colonizes roadsides and cleared land. Widely planted elsewhere and naturalized in parts of Australia, Africa, and the Americas.

Suggested Uses

Grown as a fast screen, shelter tree, and nurse plant on cleared or eroded ground, spaced 10-20 feet (3-6 m) apart. The flowers are a source of nectar and pollen for bees. Rapid growth and free seeding suit large or rural sites rather than small gardens, and the species is regarded as a weed where it has naturalized outside its range.

How to Identify

Recognized by feathery bipinnate bright green leaves, angular branchlets with raised ridges running down from each leaf base, and bright yellow globular flower heads in long sprays in late winter and spring. The raised stem ridges and the widely spaced pinnae separate it from Acacia mearnsii and Acacia dealbata, which have grey-green foliage and more crowded pinnae.

Appearance

Size & Dimensions

Height20' - 50'

Width/Spread13' - 26'

Reaches mature size in approximately 8 years

Colors

Flower Colors

yellow

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~4 weeks

Winter Spring

Flowers from July to September, with peak bloom in late winter to early spring. The yellow flower heads open over three to five weeks and carry a light scent. Flowering is heavy in most years once trees reach two to three years old.

Detailed Descriptions

Foliage Description

bright green

Growing Conditions

Sun Requirements

SunFull Sun

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

Soil Requirements

pH Range5.5 - 7.5(Neutral)

357912

Soil Types

clay loam sand

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

5-10 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grows in full sun on a wide range of well-drained clay and loam soils and tolerates exposed sites. Established trees handle drought and light frost but are damaged by hard freezes. The species fixes its own nitrogen and needs little added fertilizer, and phosphorus-rich feeds can harm the roots. Trees are short-lived and prone to borers and gall-forming insects as they age. Self-sown seedlings appear around parent trees and can spread into surrounding ground.

Pruning

Prune lightly when young to shape the crown and remove low or crossing branches. Heavy pruning into old wood is poorly tolerated and invites borer attack. Removing seed pods before they shed reduces self-seeding.