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Acacia irrorata

green wattle

Fabaceae

eastern Australia (Queensland, New South Wales, Victoria)

Attracts Pollinators Drought Tolerant

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 9–11

Overview

Acacia irrorata is an evergreen tree in the family Fabaceae, growing 15–50 feet (4.5–15 m) tall and 10–25 feet (3–7.5 m) wide. Unlike many wattles that bear flattened phyllodes, this species keeps bipinnate, fern-like leaves throughout its life, each leaf divided into many small leaflets 0.1–0.2 inch (2–5 mm) long, mid-green to grey-green. The branchlets are ridged and often finely hairy. Flowers are pale yellow to cream, packed into small globular heads about 0.2 inch (4–5 mm) across, carried in loose sprays through late spring and summer. Flat brown seed pods 2–5 inches (5–13 cm) long follow and hold several hard seeds. The tree is native to eastern Australia and grows along forest margins, in regrowth, and on disturbed ground. It grows quickly and acts as a pioneer, but it is short-lived, often declining after 15–20 years. It seeds heavily and can spread into surrounding ground, and the brittle wood is prone to breaking in wind.

Native Range

Acacia irrorata is native to eastern Australia, from Queensland through New South Wales to eastern Victoria. It grows in open forest, along watercourses, on forest margins, and on cleared or disturbed land.

Suggested Uses

Planted for fast screening, shelter, and revegetation on disturbed or cleared sites. Used as a short-lived nurse tree to shelter slower-growing species while they establish. Grown in native and habitat gardens where its flowers feed insects and seed-eating birds.

How to Identify

Identify Acacia irrorata by its bipinnate, fern-like leaves, which separate it from the many wattles that bear flattened phyllodes. The pale yellow to cream flowers form small globular heads about 0.2 inch (4–5 mm) across in loose sprays. Branchlets are ridged and finely hairy, and flat brown pods 2–5 inches (5–13 cm) long follow flowering.

Appearance

Size & Dimensions

Height15' - 50'

Width/Spread10' - 25'

Reaches mature size in approximately 7 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~10 weeks

Spring Summer

Flowering occurs through late spring and summer, roughly November to February in the native range. The pale yellow to cream globular heads are held in branched sprays. Flowering is followed by flat brown seed pods that ripen over the following months.

Detailed Descriptions

Flower Description

pale yellow to cream

Foliage Description

mid-green to grey-green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 5-9 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

3-5 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grow Acacia irrorata in full sun to part shade in most well-drained soils, including clay and sandy loams. It tolerates short dry periods once established and fixes nitrogen through root nodules. Water young trees through their first dry season to settle the roots. Growth is rapid, and the tree reaches flowering size within a few years. It is frost-hardy to light frosts once established, while young plants are damaged by hard frost. Pruning of young plants brings on a stronger single trunk.

Pruning

Prune Acacia irrorata while young to shape a single trunk and take out low or crossing branches. Acacias respond poorly to heavy cutting of old wood, so major cuts are kept to a minimum. Remove dead or storm-damaged wood as it appears.

Pruning Schedule

winter