Grevillea robusta - Evergreen Trees Direct

Grevillea robusta - Silk Oak - Evergreen Trees Direct

Grevillea robusta - Silk Oak

Name: Grevillea robusta - Silk Oak
Brand: Evergreen Trees Direct
SKU: GREVROB100L
Price: 620.00 AUD
Availability: InStock

$620.00

Tax included. Shipping calculated at checkout.

999 in stock

Size: 100L

100L 40cm/45L

Current Stock Height Guides

40cm/45L: 1.3m – 1.8m Approx.
100L: 2m – 2.4m Approx.

Trade Customers

We supply advanced trees to landscapers, developers, architects, and councils Australia-wide. Trade clients receive fast quotes, expert advice, and access to premium stock with reliable freight.

About Grevillea robusta - Silk Oak

Grevillea robusta, commonly known as Silk Oak or Australian Silver Oak, is a majestic evergreen native tree celebrated for its elegant form, fern-like pinnate foliage with silvery undersides, and vibrant orange-red flower clusters that bloom from late spring to early summer. Growing up to 30 meters tall and spreading 10–15 meters wide, this fast-growing tree creates bold scale and year-round structure in large gardens, parks, and open landscapes.

Thriving in full sun to partial shade and adaptable to various soils including clay and sand, Grevillea robusta is moderately drought-tolerant once established. Its upright, symmetrical shape with a conical crown makes it an excellent shade tree, ornamental feature, and habitat provider for native birds and pollinators. With low to moderate maintenance needs, Silk Oak is a reliable and striking choice for spacious outdoor settings that demand both beauty and ecological value.

Key Information to Know

Evergreen / Deciduous

Grevillea robusta - Silk Oak is an Evergreen (foliage year round) Tree

Mature Height & Width

Mature Height: 15m - 30m Approximately

Mature Width: 10 – 15 meters

Grevillea robusta - Silk Oak is expected to grow 40 – 60 cm per year (vigorous).

Frost Tolerance

Is Grevillea robusta - Silk Oak frost tolerant?

Grevillea robusta - Silk Oak is Frost Hardy – Survives heavy and frequent frost without damage.

Flowering Information

Grevillea robusta produces long, showy, golden-orange toothbrush-shaped flowers from late spring into early summer. These upright clusters sit above the fern-like foliage and create a striking seasonal display that stands out brilliantly against the tree’s deep green canopy.

Native Information

Is Grevillea robusta - Silk Oak an Australian Native? Yes

Grevillea robusta - Silk Oak is Native to Native to eastern Australia, where it grows in subtropical and dry rainforests of Queensland and New South Wales.

Wildlife Value

Its nectar-rich flowers attract honeyeaters, lorikeets, native bees and butterflies, making it a powerhouse for pollinators. The large evergreen canopy provides shelter and nesting habitat for birds, while the textured bark supports insects and microfauna that boost biodiversity in native and subtropical gardens.

Sunlight Information

Grevillea robusta - Silk Oak will thrive best in:

Full Sun
Part Shade

Preffered Soil

Grevillea robusta performs best in well-drained sandy or loam soils and prefers slightly acidic to neutral conditions. It may struggle in heavy clay or poorly drained areas unless improved with organic matter and coarse material to enhance drainage. Keep soil evenly moist during establishment, then transition to deep, occasional watering as the tree matures to support its drought resilience, healthy structure and reliable flowering.

Botanical Information

Common Name: Silk Oak

Genus: Grevillea

Botanical Species: Grevillea

Family: Proteaceae

Botanical Name: Grevillea robusta

Landscape Uses

Feature Tree
Rural Property Planting
Shade Tree
Screening or Privacy

Grevillea robusta - Silk Oak works in an:

Australian Native Garden – celebrates local plants with natural character.
Tropical Garden – lush, leafy planting for a resort-style atmosphere.
Modern Garden – sleek, minimal, and design-led planting.
Low-maintenance Garden – resilient choices for easy care and year-round appeal.

Planting, Spacing & Care

How to Plant Grevillea robusta:

Select an Ideal Location: Choose a location with well-draining soil and sufficient space for this tree's eventual size.

Dig the Planting Hole: Dig a hole that's as deep and twice as wide as the root ball.

Position the Tree: Place the tree in the hole, ensuring the top of the root ball is level with the surrounding soil.

Backfill with Soil: Fill the hole with soil, gently tamping it down to remove air pockets.

Water Thoroughly: Provide a generous watering to help the tree settle in.

Feature Planting: Space 8 – 10 m apart for canopy development

Hedging & Screening: Not suitable

Avenue Planting: Space 10 – 12 m apart for full crown effect

Caring for Your Grevillea robusta:

Watering: During the first few years, maintain consistent soil moisture. Reduce watering frequency as the tree matures.

Pruning: Prune to maintain shape and remove dead or damaged branches. This tree typically requires minimal pruning.

Fertilization: Apply a balanced, slow-release fertilizer in spring to promote healthy growth.

Optimal Soil Conditions for Fast Growth and Flowering

Ideal Drainage:
Thrives in well-drained soils, especially important in wetter climates.

Well-Draining Soil:
Vital to support its rapid growth and prolific flowering.

If you have the following soil, here are some tips for you:

Sandy Soils:
Clay Soils:
Loamy Soils:
Acidic or Alkaline Soils:

Grevillea robusta - Silk Oak is expected to grow 40 – 60 cm per year (vigorous).

Fast Growth Rate

Root Ball Dimensions (Width × Depth) For Planting

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 / 70L Pot: 55cm (W) × 41.8cm (D)
100L Bag: 50.6cm (W) × 52.8cm (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)

Ideal Conditions

Tropical QLD (Cairns, Townsville)
Subtropical QLD (Brisbane, Gold Coast, Sunshine Coast)
Northern NSW (Byron, Coffs, Armidale)
Sydney & Central Coast
South Coast NSW (Illawarra to Bega)
Inland NSW / Tablelands (Orange, Bathurst, Canberra)
Melbourne & Surrounds (Metro, Bayside, Geelong, Bellarine, Mornington)
Western District & Central VIC (Ballarat, Bendigo, Hamilton)
Gippsland (Latrobe Valley, East Gippsland)
Adelaide Metro & Coastal
Adelaide Hills & Barossa

Thrives in

Full Sun
Part Shade

Frost Tolerance

Frost Hardy – Survives heavy and frequent frost without damage.

Drought Tolerance

As a young tree it requires regular watering, but once established the Silk Oak develops excellent drought tolerance. Naturally adapted to warm, dry and coastal conditions, it maintains vigorous growth and good canopy density with minimal supplementary watering.

Flowering Information

Does Grevillea robusta - Silk Oak flower?

Yes - Flowers

Flowering Period:

Spring
Summer

Flower Type:

Fluffy

Flower Colour:

Yellow

Frequently Asked Questions

Frequently Asked Questions (FAQs):

Q: Can Grevillea robusta tolerate drought?
A: Yes, once established, Grevillea robusta is moderately drought-tolerant, making it suitable for regions with dry spells.

Q: What type of soil does it prefer?
A: Grevillea robusta can thrive in various soil types, including clay and sandy soils, as long as they are well-draining.

Q: Are the orange-red flowers attractive to wildlife?
A: Yes, the vibrant orange-red flowers of Grevillea robusta are known to attract birds and pollinators, adding to the tree's appeal in the garden.

youtube