Grevillea robusta (Silk Oak, Southern Silky Oak, Australian Silver Oak ) is a large evergreen tree native to the eastern coast of Australia. It belongs to the family Proteaceae and is known for its attractive foliage and vibrant flowers.
Size and Shape: Grevillea robusta is a tall tree that can reach heights of up to 30-40 meters (98-131 feet) in its natural habitat. It has a straight trunk and a spreading crown with a broad, rounded shape.
Leaves: The tree has pinnately compound leaves, meaning that each leaf is divided into multiple leaflets. The leaflets are elongated, lance-shaped, and have serrated edges. They are glossy green on the upper surface and silvery-gray beneath, giving the tree its common name "Silver Oak."
Flowers: The Silk Oak produces large and showy flowers that are a prominent feature of the tree. The flowers are arranged in clusters at the ends of the branches and are typically a vibrant orange to reddish-orange color. Each individual flower has a unique, spider-like shape with long, slender petals.
Fruit: After the flowers fade, small woody fruits known as follicles develop. These follicles contain seeds and are typically brown or gray in color. They persist on the tree for some time before eventually opening and releasing the seeds.
Habitat and Adaptability: Grevillea robusta is native to the subtropical and tropical rainforests of eastern Australia, including parts of New South Wales and Queensland. It thrives in well-drained soils and prefers full sun or partial shade. It can tolerate a range of soil types, including sandy or clay soils.
Uses: The Silk Oak is often cultivated as an ornamental tree due to its striking appearance. It is valued for its attractive foliage, vibrant flowers, and the dappled shade it provides. The wood of Grevillea robusta is also used in various applications, such as furniture, cabinetry, and construction.
Botanical Name : Grevillea robusta
Common Name : Silk-Oak Tree
Height : 70 ft
Spread : 40 ft
Germination Info : Soak in water 48 hours then cold stratify for 30 days. Seed needs light to germinate.
Hardiness zone : 10-11
Average seed per ounce : Approx. 2500