Brisbane tree guide

Silky oak

Grevillea robusta · also called Southern silky oak, Silk oak

The silky oak is a tall Brisbane native with fern-like leaves and brilliant golden-orange flower spikes in spring that draw nectar-feeding birds and flying-foxes. It grows naturally along the coast and ranges of south-east Queensland and northern New South Wales. Council plants it on wide verges, where it reaches 15 to 20 metres, so a silky oak needs a big garden and distance from sewer pipes.

Native to South East Queensland
15 to 20 m tall
Flowers September to November

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Silky oak, from Wikimedia Commons — Photo: MargaretRDonald, CC BY-SA 4.0, via Wikimedia Commons

Silky oak at a glance

Height: 15 to 20 m (up to 40 m in the wild)
Leaves: Semi-deciduous
Flowers: Orange, yellow, September to November
Roots: Aggressive
Origin: Coast and ranges from about Coffs Harbour in NSW to Bundaberg in Queensland
Power lines: Not on the council's list for under power lines
Family: Proteaceae

How to identify a silky oak

A tall, upright tree, 15 to 20 metres in Brisbane streets, that is often partly deciduous for a time each year. The leaves are fern-like, 10 to 34 cm long and deeply cut into narrow lobes, with silky, silvery-white hairs underneath. In spring it carries one-sided, comb-like flower spikes 12 to 16 cm long, golden yellow to orange. Small flattened pods follow, each holding winged seeds. The tree waratah, which is also called red silky oak, has undivided leaves and red flowers.

Growing a silky oak in Brisbane

Silky oak is a true local: it grows naturally in riverside rainforest and forest from about Coffs Harbour to Bundaberg, and the species was first collected for science near Moreton Bay in 1827. Brisbane City Council uses it as a street tree on higher ground and arterial roads, but only on verges wider than 5 metres and not under power lines. In a garden it needs plenty of space. The biggest flower shows tend to follow a hot, dry end to winter.

What to watch out for

Silky oak is a big tree: 15 to 20 metres in Brisbane streets and up to 40 metres in the wild. Hunter Water gives it a high damage rating for sewer pipes, so plant it well away from sewer lines. The sawdust, and occasionally the foliage, has been reported to cause contact dermatitis, so cover up when pruning or cutting it.

Irritant sap or hairs. The sawdust, and occasionally the foliage, has been reported to cause contact dermatitis.
Size. It grows 15 to 20 m tall in Brisbane streets and up to 40 m in the wild.

Pruning and care

Silky oaks need little pruning once established. Remove dead wood and crossing branches and lift low limbs for clearance, keeping cuts small. Wear gloves and long sleeves when pruning or handling the timber, because the sawdust and sometimes the leaves can cause skin rashes. Young trees appreciate a deep watering in dry spells. Large limbs over roofs, driveways or power lines are a job for a qualified arborist.

Silky oak: your questions

Short answers, from the sources below.

Back to the tree guide

Is silky oak native to Brisbane?

Yes. Silky oak grows naturally along the coast and ranges from about Coffs Harbour to Bundaberg, and it was first collected for science near Moreton Bay in 1827.

When does silky oak flower in Brisbane?

Mainly from September to November, with golden-orange flower spikes that attract nectar-feeding birds and flying-foxes. The best displays tend to follow hot, dry weather in late winter and spring.

Are silky oak roots invasive?

They can cause problems. Hunter Water gives silky oak a high damage rating for sewer pipes, so keep it well away from sewer lines.

Can silky oak cause a rash?

It can. Flora of Australia notes that the sawdust, and occasionally the foliage, has been reported to cause contact dermatitis, so wear gloves and long sleeves when pruning or cutting it.

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Sources and credits

Photo: MargaretRDonald, CC BY-SA 4.0, via Wikimedia Commons.

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