Brisbane tree guide

Ferny wattle

Acacia decurrens · also called Green wattle, Sydney green wattle, Early black wattle

Ferny wattle is a Queensland name for Acacia decurrens, better known elsewhere as green or Sydney green wattle: a small, fast-growing tree with dark green, fern-like leaves and bright yellow ball flowers in late winter and early spring. It is native to New South Wales, not Brisbane. It has naturalised in parts of south-east Queensland, and the Queensland Government's WildNet database flags it as an environmental weed.

Australian native
3 to 10 m tall
Flowers July to September

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Ferny wattle, from Wikimedia Commons — Photo: J Brew, CC BY-SA 2.0, via Wikimedia Commons

Ferny wattle at a glance

Height: 3 to 10 m (up to 15 m in the wild)
Growth: Fast
Leaves: Evergreen
Flowers: Yellow, July to September
Origin: Central and southern New South Wales, from the Hunter Valley to the ACT
Family: Fabaceae

How to identify a ferny wattle

A tall shrub or small tree, usually 3 to 10 metres, with dark green, fern-like leaves. Each leaf splits into 3 to 13 pairs of side branches lined with narrow leaflets 5 to 15 mm long, and the stems carry raised ridges running down from the leaf bases, which is what 'decurrens' refers to. Fluffy, bright yellow ball flowers appear in late winter and early spring, followed by flat brown pods 2 to 10 cm long. Black wattle (Acacia mearnsii) looks similar, but its leaflets are much shorter, its young stems are hairy and it carries paler, creamy flower balls.

Growing a ferny wattle in Brisbane

Ferny wattle comes from the Sydney region and nearby tablelands. Away from home it has mostly run wild in cooler districts, and in south-east Queensland it is seen as an emerging weed, mainly in the higher country around Toowoomba and Stanthorpe. The Australian Native Plants Society suggests this group of wattles is not ideal for small suburban gardens. For a wattle that belongs here, Brisbane wattle (Acacia fimbriata) is native to Brisbane and is offered through Council's free native plant program.

What to watch out for

This wattle is not declared under Queensland law and is not on Brisbane City Council's weed list, but the Queensland Government's WildNet database records it as naturalised and flags it as an environmental weed. It spreads by seed. Like other wattles in the black wattle group, it is prone to borers and can decline after 7 to 8 years, by which time it can be a big, spreading tree that is hard to remove safely.

Seedlings. Outside its natural range it spreads by seed carried by ants, wind and water, and it has naturalised in parts of south-east Queensland.
Size. Borers often attack wattles in this group, and trees can decline after 7 to 8 years, by which time they are large, spreading and hard to remove safely.

Pruning and care

Keep pruning light. Shape young plants lightly in their early years, and never cut back into bare wood: most wattles won't recover from a severe prune, so always leave green foliage below each cut. Dead branches can be removed at any time. Watch for borer holes and sawdust on the trunk, and pull out seedlings that come up nearby. A large tree that is declining or leaning towards a house or fence is a job for a qualified arborist.

Ferny wattle: your questions

Short answers, from the sources below.

Back to the tree guide

What is ferny wattle?

Ferny wattle is a Queensland name for Acacia decurrens, a New South Wales wattle also called green wattle, Sydney green wattle or early black wattle. It has dark green, fern-like leaves and bright yellow ball flowers.

Is ferny wattle native to Brisbane?

No. Ferny wattle is native to central and southern New South Wales. It has naturalised in parts of south-east Queensland, mostly in cooler upland areas, and WildNet flags it as an environmental weed.

How long do ferny wattles live?

Not long. Wattles in this group grow very fast but often decline after 7 to 8 years as borers take hold, while many wattles live 12 to 15 years or more in good conditions.

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Sources and credits

Photo: J Brew, CC BY-SA 2.0, via Wikimedia Commons.

This profile updates sheet 29 of the plant profile booklet made for Colourful Tree Lopping in 2013. We checked every fact against current sources and rewrote it for the guide.

Checked October 2026. Weed listings and council rules change: check the council's and the Queensland Government's pages before you act.