Silky Oak (Grevillea robusta)
Robusta
About this plant
Grevillea robusta, commonly known as Silky Oak, is a tall evergreen tree with fern-like leaves and bright orange flowers that attract birds. It is valued for its attractive timber and as an ornamental tree in gardens and parks. The tree is native to Australia and is known for its fast growth and striking appearance.
Taxonomy
Higher classification: Order Proteales
Origin & Distribution
- Native region
- Australia
- Distribution
- Native to eastern Australia; widely cultivated in subtropical and tropical regions worldwide.
Care
- Suitable locations
- Outdoor, Balcony, Greenhouse
- Preferred window facing
- South-facing, West-facing, East-facing
- USDA hardiness zones
- 9–11
- Soil pH
- 5.5–7.5
- Soil type
- well-draining loam, sandy soil
Watering. Water regularly during the first year to establish roots, then reduce frequency. Allow soil to dry out between watering to prevent root rot.
Fertilizing. Feed with a balanced fertilizer in spring and summer to support growth. Avoid high-phosphorus fertilizers as the plant prefers low phosphorus levels.
Grevillea robusta is a fast-growing tree that prefers full sun and well-draining soil. It is drought-tolerant once established but needs regular watering when young. It can be sensitive to frost and may require protection in colder climates. Pruning helps maintain shape and remove dead wood.
Propagation
- Propagation methods
- Seeds, Cuttings
Ornamental features
- Flowering
- Yes
- Flowering period
- spring–summer
Fern-like foliage, bright orange spider-like flowers, attractive timber grain.
Toxicity & Safety
Sap can cause skin irritation; keep away from children and pets to avoid contact.
Allergy information
Grevillea robusta can cause allergic reactions in some people, especially from its pollen and sap. Those sensitive may experience skin irritation or respiratory symptoms. To reduce exposure, avoid direct contact with the sap and wear a mask during its flowering season.
Common problems
Problems include leaf scorch if exposed to too much heat without water, root rot from overwatering, and occasional pest attacks like aphids or scale insects.
Uses
Used as an ornamental tree for shade and decoration; timber is valued for furniture and woodworking.
Notes
Prune after flowering to maintain shape and encourage bushier growth. Repot young plants annually if grown in containers. Protect from frost and strong winds.