Grevillea robusta Proteaceae
Silky Oak, Australian Silk Oak, Silk Oak
- Broadleaf evergreen tree, tall, fast growing to 115 ft (35 m), may reach 165 ft (50 m) in its habitat,
symmetrical, pyramidal when young, old trees have broad tops (30-35 ft, ~9-11 m), branches have silvery pubescent.
Leaves alternate, pinnately compound ("fern-like”), 15-30 cm long, the pinnae (leaflets) usually further
bipinnate, lanceolate, margin involuted (rolled inward toward the upper surface), dark green above, silky
pubescent below. Flowers golden orange-yellow, produced singly or in 2s or 3s, in one sided
racemes, 7-12 cm long, style prominent (2 cm), flowering only occurs in trees in a subtropical and tropical
- Sun, does well in heat. A valuable, fast growing, shade tree in the tropics and subtropics. Brittle in
high winds. Heavy leaf drop in the spring, sporadic drop throughout the year. A popular
potted plant in cooler climates (Sunset, 2007).
- Hardy to USDA Zone 8 [Young trees injured at 24° F…older trees at 1° F (Sunset,
2007)] Native to Australia (Queensland and New South Wales); considered a weed in parts of