Skip to content

Volume Discounts Apply At Checkout

Grevillea robusta - Silk Oak

Grevillea robusta - Silk Oak

Most loved for its fern-like foliage, masses of golden-orange flowers in spring, and strength as a fast-growing shade and feature tree.

Regular price $280.00
Sale price $280.00 Regular price
Tax included. Shipping calculated at checkout.
Pot size
Available batches
Size: 40cm/45L
Current height guide
Please enquire
Pot size
40cm/45L

Approximate only. Minimum height important? Confirm with us.

Height guide & disclaimer

Height guide disclaimer: Height ranges are approximate only. As living products, plant heights naturally vary between individual plants, batches, and seasons. No guarantee is given that supplied plants will fall within the stated range. If minimum heights are required, you must confirm current batch heights with Evergreen Trees Direct prior to purchase. Variation in height is normal and is not grounds for return, refund, replacement, or compensation.

Quantity

Order multiple sizes

Mix pot sizes and batches in one order.

Size / batchEachQuantity
40cm/45LApprox. height: Approx. 1.5m – 2.2m$280.00
100LApprox. height: Approx. 2.4m – 3.0m$700.00
200LApprox. height: Approx. 2.4m – 3.0m$1,650.00

Height guide & disclaimer

Height guide disclaimer: Height ranges are approximate only. As living products, plant heights naturally vary between individual plants, batches, and seasons. No guarantee is given that supplied plants will fall within the stated range. If minimum heights are required, you must confirm current batch heights with Evergreen Trees Direct prior to purchase. Variation in height is normal and is not grounds for return, refund, replacement, or compensation.

Subtotal before discounts & delivery$0.00

Delivery is calculated at checkout.

Ask a question

The fields marked * are required.

Not sure how many trees you need?

Plan your hedge

Enter the length of your boundary, then choose how closely you want to plant.

Choose your planting spacing

Enter your boundary length to see how many trees you need.

Measure only the boundary you intend to plant—exclude gates and gaps. Spacing is centre to centre. Quantities are rounded up for one row, allowing roughly half the spacing at each end. Site conditions and pruning affect the final hedge.

Compare trees

Choose two trees and compare the same pot size.

    About Grevillea robusta

    Grevillea robusta carries large golden-orange toothbrush flowers across the whole canopy in spring and early summer, drawing honeyeaters and lorikeets in numbers few other trees manage. Fine fern-like foliage gives it a lightness unusual in a tree of this scale.

    The Silk Oak grows to 15 to 30 metres tall and 10 to 15 metres wide at 40 to 60 centimetres per year, forming an upright pyramidal frame when young that broadens with age. It is used for shade, shelter and feature planting on acreage, rural properties and in large civic landscapes.

    This Australian native is frost hardy, surviving heavy and frequent frost without damage, and tolerates poor soils and extended dry once established. It grows in full sun to part shade and needs free drainage, along with low-phosphorus feeding like all Proteaceae.

    Frequently Asked Questions

    About Grevillea robusta

    How big does Grevillea robusta grow?

    The Silk Oak reaches 15 to 30 metres tall and 10 to 15 metres wide. It is a large tree best suited to acreage, rural properties and parkland rather than small suburban blocks.

    How fast does Silk Oak grow?

    It grows vigorously at 40 to 60 centimetres per year, and considerably faster in warm frost-free conditions with reliable moisture.

    When does Grevillea robusta flower?

    Large golden-orange toothbrush flowers appear through spring and into summer, carried heavily across the canopy. They are a major nectar source for honeyeaters and lorikeets.

    Is Grevillea robusta an Australian native?

    Yes. It is native to the subtropical rainforest margins of eastern Australia and is the largest species in the Grevillea genus.

    What feeding does Silk Oak need?

    Use only low-phosphorus native fertiliser. Like all Proteaceae, Grevillea robusta is damaged by high-phosphorus formulations, which can kill established trees.

    Is Grevillea robusta frost hardy?

    Yes, once established it survives heavy and frequent frost without damage. Young trees benefit from protection through their first winter in cold districts.

    How far apart should I plant Silk Oak?

    Plant 8 to 10 metres apart for a shelterbelt or avenue, and at least 10 metres from buildings and services given its eventual size.

    Foliage

    Evergreen (foliage year round)

    Position
    • Full Sun
    • Part Shade
    Form
    • Upright
    • Spreading
    Use
    • Feature Tree
    • Rural Property Planting
    • Shade Tree
    • Screening or Privacy
    Mature height
    15m to 30m (approx.)
    Mature width
    10m to 15m

    Planting Information

    How To Plant Your Grevillea robusta - Silk Oak

    Site: Choose a well-drained position in full sun to part shade with room for the canopy to develop.

    Soil preparation: Enrich the planting area with quality compost and aged manure for a strong establishment phase.

    Hole: Dig twice as wide as the root ball and the same depth.

    Planting: Position level with the surrounding soil, backfill gently, firm in, then water deeply to settle the roots.

    Recommended Planting Spacing For Your Grevillea robusta - Silk Oak

    Feature tree: 3 to 4 metres apart to allow the full canopy and form to develop.

    Avenue planting: 3 metres apart for a uniform soft-textured avenue.

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

    • Fast Growth Rate

    Long Term Care For Your Grevillea robusta - Silk Oak

    Watering: Water deeply twice weekly through the first 12 months. Once established, this is drought tolerant and only needs a deep soak during extended dry periods.

    Mulching: Apply a 5 to 7 centimetre layer of organic mulch over the root zone, keeping it 5 centimetres clear of the trunk.

    Pruning: Minimal pruning required. Light tip prune in late winter to maintain shape, and remove lower branches as the tree grows to develop a clean feature trunk.

    Fertilising: Apply a slow-release native blend in early spring and again in autumn. Avoid high-phosphorus formulations as a precaution.

    Pest and disease: Hardy against most pests and diseases. Occasional inspection in warm humid conditions is all that's needed.

    Planting Your Grevillea robusta - Silk Oak in Different Soil

    Grevillea robusta performs best in well-drained sandy loam or loam with a slightly acidic to neutral pH. Adaptable to a wide range of soils when drainage is improved with organic matter.

    Sandy soil: Free-draining and ideal. Mulch well to maintain consistent moisture.

    Clay soil: Improve drainage with gypsum and organic compost before planting.

    Loam: The preferred soil for steady root development and consistent growth.

    pH: Slightly acidic to neutral preferred. Mulch with composted leaf litter to maintain levels naturally.

    Uses in my Garden

    Uses in my Garden

    • 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.

    Is Grevillea robusta - Silk Oak Evergreen or Deciduous?

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

    Mature Height & Width

    Mature Height: 15m to 30m (approx.)

    Mature Width: 10m to 15m

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

    Growth Rate of Grevillea robusta - Silk Oak

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

    They are considered to have a:

    • Fast Growth Rate

    Frost Tolerance & Ideal Climate to plant Grevillea robusta - Silk Oak

    Is Grevillea robusta - Silk Oak frost tolerant?

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

    Does Grevillea robusta - Silk Oak Flower?

    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.

    Does Grevillea robusta - Silk Oak flower?

    • Yes - Flowers

    Flowering Period:

    • Spring
    • Summer

    Flower Type:

    • Fluffy

    Flower Colour:

    Yellow

    Is Grevillea robusta - Silk Oak an Australian Native Tree?

    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.

    What is the Wildlife Value of Grevillea robusta - Silk Oak ?

    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.

    How much Sunlight does Grevillea robusta - Silk Oak need?

    Grevillea robusta - Silk Oak will thrive best in:

    • Full Sun
    • Part Shade

    Preferred 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.

    Is Grevillea robusta - Silk Oak Drought Tolerant?

    Is Grevillea robusta - Silk Oak Drought tolerant?

    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.

    Frequently Asked Questions

    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.

    Compare sizes side by side

    40cm/45L

    Approx. 1.5m – 2.2m

    100L

    Approx. 2.4m – 3.0m

    200L

    Approx. 2.4m – 3.0m

    Heights are approximate and vary between individual trees.

    Grevillea robusta is loved for its fern-like foliage, masses of golden-orange flowers in spring, and strength as a fast-growing shade and feature tree.

    We take pride in supplying A+ grade advanced trees. When stock at our farm is not yet ready, we work with our trusted trade suppliers to source the best available trees for your garden.

    Plant Your Grevillea robusta - Silk Oak With:

    Enriched Planting Mix (AO Certified)

    Enriched Planting Mix is a certified organic blend of Pure Magic Compost, composted animal manure, gypsum, composted coarse bark and a wetting agent, bagged in 30L. It is built to be dug through existing garden soil at planting time rather than used on its own, and the gypsum is what sets it apart from a plain compost.

    Gypsum helps break up heavy clay so water and roots can move through it, while the compost and manure return organic matter and nutrient to tired ground. The coarse bark holds structure and keeps air around the root zone, and the wetting agent keeps moisture in the soil longer after rain or watering.

    Use it when planting trees, shrubs, roses, fruit trees and exotic garden plants, particularly into clay. Dig a hole twice the width of the pot and 7 centimetres deeper, then mix roughly one third planting mix through the excavated soil. Spread 7 centimetres of that improved soil in the base before setting the plant in.

    Frequently Asked Questions

    About Enriched Planting Mix

    What is Enriched Planting Mix made from?

    It is a blend of Pure Magic Compost, composted animal manure, gypsum, composted coarse bark and a wetting agent. Each part has a job. The compost and manure supply organic matter and nutrient, the gypsum works on clay structure, the bark keeps air around the roots and the wetting agent holds moisture in the soil.

    What plants is it suitable for?

    It suits exotic garden plants, including roses, ornamental and deciduous trees, fruit trees, shrubs and perennials, and it earns its keep most on heavy clay sites. It is a planting mix rather than a potting mix, so its job is improving soil at planting time. Phosphorus sensitive natives are the one clear exception.

    Is it safe for natives?

    No, not for the phosphorus sensitive ones. The composted animal manure in this blend lifts phosphorus well above what Proteaceae such as Banksia, Grevillea, Hakea and Protea will tolerate, and the result can be leaf burn, dieback and plant death. Use the Native Potting Mix for those species, or plant them into unimproved local soil.

    Is it certified organic?

    Yes. It is a certified organic product with no chemical additives, which is why the manure and compost in it are fully composted rather than raw. That makes it sound around fruit trees and vegetable beds, and it means you are adding genuine organic matter to your soil rather than a synthetic conditioner.

    How much do I need?

    Work on roughly one third planting mix to two thirds of the soil you dug out of the hole. For a shrub out of a 200 millimetre pot that is only a few litres. An advanced tree going into a large hole will take considerably more. Judge the quantity by the volume of the hole rather than the size of the plant.

    Can I use it in pots?

    It is not a potting mix and should not be used on its own in a container. The blend is designed to be diluted through garden soil, and used straight in a pot it holds too much water and settles badly. For containers, reach for a premium potting mix, or the native mix if you are potting natives.

    Does it need to be watered in?

    Yes. Water the plant well several hours before you plant it, then water thoroughly again once the hole is backfilled and the soil firmed down. That first deep watering settles the improved soil around the root ball and drives out air pockets. Keep the water up over the first few months while the roots establish.

    youtube Load video:

    Evergreen Trees Direct Has Been Featured In:

    Perfect Substitutes for Grevillea robusta - Silk Oak

    Follow Us On Instagram

    @evergreentreesdirect ↗
    Evergreen Trees DirectEvergreen Trees DirectEvergreen Trees DirectEvergreen Trees DirectEvergreen Trees Direct
    youtube Load video: