Silky Oak Grace Smith/ClimateWatcher

Silky Oak

Grevillea robusta

Did You Know?

  • Sawdust from the Silky Oak, and sometimes its foliage, can cause contact dermatitis
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Named in 1830 by explorer and botanist, Allan Cunningham. The genus name Grevillea honours Charles F Greville who co-founded the Royal Horticultural Society, and the species name robusta refers to its large size.

Evergreen tree usually grows 20 – 30 m tall but can range from 8 – 40 m in height.

Leaves

Silvery green and fern-like, green on the upper surface and paler underneath. They are 10 – 34 cm long and 9 – 15 cm wide, and consist of 11 – 31 segments that are narrow-elliptic to triangular in shape. The segments are 1.5 – 5 cm long and 2 – 10 mm wide, and they give the leaf a deeply divided appearance.

Flowers

Golden yellow to orange, each one is about 2 cm long but they are arranged in pairs along the flowering stalk to give an overall length of 12 – 15 cm.

Fruits/Seeds

A dark-brown, smooth seed pod, oval in shape and slightly flattened. It is about 2 cm long.

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What to Observe

  • First fully open single flower

  • Full flowering (record all days)

  • End of flowering (when 95% of the flowers have faded)

  • Not flowering

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When and Where

When To Look

  • From September through to January
  • Flowers appear in spring (mainly from September to November but later in cooler areas)
  • Mature seed pods appear in December and January

Where To Look

  • On the coast and coastal ranges of southern Queensland and northern NSW, from Bundaberg south to Coffs Harbour, and to about 150 km inland
  • Grows in most areas along the east coast but needs shelter from the cold and frost when young
  • In subtropical to dry rainforests, forests with tall trees and fern-like ground cover, and sometimes along riverbanks and stream banks
  • It can also be found on higher slopes amongst conifer trees and vines
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What Else?

Similar Species

The Silky Oak is a very distinct tree and unlikely to be confused with anything else.