Brisbane tree guide

River she-oak tree

Casuarina cunninghamiana · also called River oak, River sheoak, She oak

River she-oak is the tall, wispy she oak tree that lines freshwater creeks and rivers around Brisbane and through much of eastern Australia. Its drooping, needle-like branchlets whistle softly in the wind, birds feed on the seed in its small cones, and its roots add nitrogen to the soil. It is a big tree, though, reaching 15 to 35 metres, and its roots need distance from pipes.

Native to South East Queensland
15 to 35 m tall

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River she-oak, from Wikimedia Commons — Photo: No machine-readable author provided. Rickjpelleg assumed (based on copyright claims)., CC BY 2.5, via Wikimedia Commons

River she-oak at a glance

Height: 15 to 35 m (up to 50 m in the wild)
Leaves: Evergreen
Flowers: Small and easy to miss
Roots: Aggressive
Origin: Freshwater streams of eastern Queensland and NSW, from Laura to Bega, with another subspecies in the Top End
Family: Casuarinaceae

How to identify a river she-oak

River she-oak has grey-brown bark that is finely fissured and scaly. Its fine, drooping green 'needles' are really jointed branchlets, and the true leaves are tiny teeth, 6 to 10 in a ring at each joint; counting the teeth is how she-oaks are told apart. Male and female flowers grow on separate trees. Male trees take on a rusty brown tinge when in flower, and female trees carry small woody cones 7 to 14 mm long. Swamp oak, Casuarina glauca, is a related she-oak that tolerates swampy and slightly salty ground.

Growing a river she-oak in Brisbane

River she-oak is a local native. It grows naturally along permanent freshwater streams in the Brisbane area and through much of eastern Queensland and New South Wales, and it is often planted in parks and urban areas and used as a windbreak. At 15 to 35 metres it suits large gardens, acreage, parks and creek banks rather than small suburban blocks. Give it full sun, and keep it well away from water and sewer pipes.

What to watch out for

Size and roots are the main concerns. River she-oak can grow 15 to 35 metres tall, and Burke's Backyard recommends planting it about 15 metres from water and sewer pipes, so it is better suited to parks and large gardens. It also drops a steady carpet of fine branchlets. Big trees near buildings or power lines are a job for a qualified arborist.

Size. It grows 15 to 35 metres tall, occasionally more, so it suits large gardens and parks rather than suburban yards.
Mess. It sheds fine branchlets that build up into a thick mat under the tree.

Pruning and care

She-oaks need little care. Prune young trees lightly to remove crossing or damaged branches and to lift the canopy where needed, and take out dead wood as it appears. Leave the fallen branchlets as mulch if you can: they don't poison the soil, as people once thought, and they help suppress weeds and hold soil in place. Keep young trees watered for several weeks after planting while they settle in.

River she-oak: your questions

Short answers, from the sources below.

Back to the tree guide

How tall does a river she-oak grow?

River she-oak usually grows 15 to 35 metres tall and occasionally reaches about 50 metres in the wild, so it needs a large space.

Are she oak tree roots invasive?

River she-oak roots can be a problem near plumbing. Burke's Backyard recommends planting river oaks about 15 metres away from water and sewer pipes.

Do she-oak needles poison the soil?

No, that's an old myth. The fallen branchlets make a mulch that suppresses weeds and helps stop erosion, and the roots add nitrogen to the soil.

Why does my she-oak look brown?

Many she-oaks turn reddish brown when the male trees flower, usually in autumn and winter. The colour comes from masses of tiny flowers at the branchlet tips, not from the tree dying.

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Sources and credits

Photo: No machine-readable author provided. Rickjpelleg assumed (based on copyright claims)., CC BY 2.5, via Wikimedia Commons.

This profile updates sheet 19 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.