








Grevillea robusta - Silk Oak
- Regular price
- $570.00
- Sale price
- $570.00
- Regular price
-
Learn About Your New Grevillea robusta - Silk Oak
Grevillea robusta – Silk Oak is a fast-growing, evergreen Australian native tree admired for its elegant form, fern-like foliage, and showy orange-red flowers. Reaching up to 30 metres in height with a spread of 10–15 metres, this large tree delivers bold scale and striking seasonal display in parks, large gardens, and open landscapes.
The foliage of Grevillea robusta – Silk Oak is one of its standout features — pinnately divided, fern-like leaves with a soft silver underside that creates a lush, textured appearance. From late spring to early summer, it produces large clusters of vibrant orange-red flowers, which attract native birds and pollinators.
It thrives in full sun to partial shade, performs well in a wide range of soils including clay and sand, and is moderately drought-tolerant once established. Its upright, symmetrical form and conical crown make it suitable as a shade tree, ornamental feature, or habitat tree in larger settings.
Grevillea robusta – Silk Oak is a strong performer where space allows, offering year-round structure, seasonal colour, and valuable habitat for wildlife — all with minimal maintenance once established.
Key Details
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Botanical Name: Grevillea robusta
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Common Names: Silk Oak, Australian Silver Oak
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Mature Height: Up to 30 metres
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Mature Width: Typically 10–15 metres
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Foliage: Fern-like, pinnate leaves with silver underside
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Flowers: Orange-red clusters, spring to early summer
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Form: Tall, upright with conical crown
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Sunlight: Full sun to part shade
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Soil: Tolerates a variety of soils, including clay and sand
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Drought Tolerance: Moderate once established
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Maintenance: Low to moderate
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Water Needs: Regular during establishment; low thereafter
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Uses: Shade tree, feature planting, habitat planting, large landscapes
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Evergreen/Deciduous: Evergreen
Everything You Need to Know Before Planting Grevillea robusta - Silk Oak
Planting Tips for Grevillea robusta - Silk Oak
Root Ball Dimensions (Width × Depth) & Planting Guide for Grevillea robusta - Silk Oak
Use this as a reference when digging your planting hole. We recommend digging at least 10% wider than the dimensions below to encourage strong root development.
- 30cm Pot: 33cm (W) × 30cm (D)
- 40cm/45L Pot: 44cm (W) × 41.5cm (D)
- 50cm Pot: 49.5cm (W) × 35.2cm (D)
- 70L Pot: 55cm (W) × 41.8cm (D)
- 100L Bag: 50.6cm (W) × 52.8cm (D)
- 100L Pot: 66cm (W) × 49.5cm (D)
- 150L Bag: 66cm (W) × 55cm (D)
- 200L Bag: 71.5cm (W) × 60.5cm (D)
- 300L Bag: 88cm (W) × 63.8cm (D)
- 400L Bag: 99cm (W) × 66cm (D)
- 500L Bag: 122cm (W) × 66cm (D)
- 750L Bag: 134cm (W) × 69cm (D)
- 1000L Bag: 146.3cm (W) × 71.5cm (D)
- 2000L Bag: 176cm (W) × 82.5cm (D)
Growing Grevillea robusta - Silk Oak in Various Soil Types
Watering Requirements After Planting Your Grevillea robusta - Silk Oak
When planting a new tree or shrub, proper watering is essential to ensure healthy establishment and long-term growth. Follow these guidelines to give your plant the best start:
- Immediately After Planting:
Water generously right after planting to settle the soil around the roots and eliminate air pockets. This helps the roots make good contact with the soil. - First Three Months (Establishment Phase):
The initial three months are critical for root development. Water deeply twice daily (morning and evening) to encourage strong, deep root growth. - Irrigation Systems:
If using an irrigation system, adjust it to provide adequate water during the establishment phase. Ensure the water reaches the root zone without overwatering. - Weather Considerations:
Adjust watering based on weather conditions. Increase frequency during hot, dry periods and reduce it during cooler, wetter seasons. - Ongoing Care:
After the establishment phase, gradually reduce watering frequency but ensure the plant receives consistent moisture, especially during dry spells.
By providing consistent and appropriate watering during the initial months, you’ll help your new tree or shrub establish a strong root system and thrive in your garden.
Frequently Asked Questions About Grevillea robusta - Silk Oak
Growing Your Grevillea robusta - Silk Oak in Various Soil Types
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