Grevillea robusta, commonly known as the southern silky oak or Silky-oak, or Australian Silver-oak, is the largest species in the genus Grevillea. It is a native of eastern coastal Australia, in riverine, subtropical and dry rainforest environments receiving more than 1,000 mm per year of average rainfall. It is a fast growing evergreen tree, between 18–35 m tall with dark green delicately dented bipinnatifid leaves reminiscent of a fern frond. It is the largest plant in the Grevillea genus, reaching diameters in excess of one metre. These leaves are generally 15–30 cm long with greyish white or rusty undersides. Its flowers are golden-orange bottlebrush-like blooms, between 8–15 cm long, in the spring, on a 2–3 cm long stem and are used for honey production. The seeds mature in late winter to early spring, fruiting on dark brown leathery dehiscent follicles, about 2 cm long, with one or two flat, winged seeds.
Uses
Before the advent of aluminium, the timber from this tree was widely used for external window joinery as it is resistant to rotting. It was also popular for making furniture. There are severe restrictions on the harvesting of this tree now as the number of trees became depleted. Silky Oak is a valuable timber and was one of Australia’s best known cabinet timbers.
It is the best tree which can be used for fencing and it is one of the fastest growing trees.
Cultivation
When young it can be grown as a
houseplant where it can tolerate light shade, but prefers full sun as it grows best in warm zones. If planted outside, young trees need protection on frosty nights. Once established it is hardier and tolerates temperatures down to about −8 °C (17 °F). It needs occasional water but is otherwise fairly drought-resistant.
Grevillea robusta is often used as stock for grafting difficult-to-grow grevilleas.
Care needs to be taken when planted near bushland as it can be weedy.
Grevillea robusta (Southern Silky Oak) is also grown in plantations in South Africa and can also be grown along side maize in agroforestry systems.
Toxicity and allergic reactions
The flowers and fruit contain
toxic hydrogen cyanide. Tridecylresorcinol in
G.robusta is responsible for
contact dermatitis.
References
External links
Grevillea robusta fact sheet on Forest, Farm, and Community Tree Network (FACT Net)
Germplasm Resources Information Network: Grevillea robusta
Plants of Hawaii (images): Grevillea robusta
Category:Invasive plant species
robusta
Category:Trees of Australia
Category:Proteales of Australia
Category:Honey plants
Category:Drought-tolerant trees
Category:Ornamental trees
Category:Flora of New South Wales
Category:Flora of Queensland
Category:Naturalized trees of Hawaii
