Accession Count: 4
Common Name:
silk oak
Family Name:
Proteaceae
Botanical Name:
Grevillea robusta
Sub Species:
Variety:
Forma:
Cultivar:
Characteristics:
This massive tree reaches heights of 50-feet or more with a 25-foot spread. The crown is pyramidal oval shaped, developing a thick trunk and several heavy horizontal limbs. The light ferny leaves are gray-green above and silvery beneath. They are two to four inches long and pinnate. Although this is an evergreen, a great number of leaves drop in the spring and are immediately replaced with new growth. Large clusters of bright yellow flowers form in the spring. Black, hard, leathery, seed capsules follow the flowers (1).
Compound:
Gre rob
Geographic Origin:
Australia
Ecozone Origin:
Australasia
Biome Origin:
AU
Natural History:
The native population of G. robusta is located in eastern parts of Australia such as, South-east Queensland and north-eastern New South Wales. This invasive plant has naturalized in many places in Australia (coast of New South Wales, Lord Howe Island, Northfolk Island). This has been distributed and then naturalized over seas (South Africa, New Zealand, Hawaii, French Polynesia, Jamaica and south-eastern USA (i.e. Florida)) (2).
Cultivation Notes:
The G. robusta is very susceptible to chlorosis, meaning it can easily lose some of its green colors. Full sun or partial shade, with moderate amounts of water, is acceptable growing conditions. In prime conditions, it is a very fast grower and needs a large amount of space in order to grow to its full extent (1).
Ethnobotany:
This large tree is planted as an ornamental, prized for its showy flowers. It is also used for lumber especially in its native Australia where it is a valuable timber source. The large, colorful flowers often attract bees and birds to pollinate. Many times it is used along streets or walkways because of its large size and the fact that it provides shade (1).
Height:
50 - 100 feet
Width:
20 - 50 feet
Growth Rate:
Fast Growing
Grow Season:
Summer
Flower Season:
Spring
Color:
Yellow
Function:
Accent
Spread:
Non-spreading
Allergen:
Non-allergenic
Invasive:
Benign
Toxicity:
Benign
Hardy:
Semi-hardy
Water Use:
Moderate Water Use
Citations:
- Perry, Bob. Landscape Plants for Western Regions: An Illustrated Guide to Plants for Water Conservation. Land Design Publishing, 1992.
- .lucidcentral.org
