Photo of Grevillea robusta flower by Alvesgaspar

Photo by Alvesgaspar

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Grevillea robusta

Also Known As

  • Australian Silky Oak
  • Silky Oak
  • Southern Silky Oak

Plant type

tree

size

  • H: 40'-60'
  • W: 20'-35'

planting zones

  • 9a-10b

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Grevillea robusta plant details

Grevillea robusta is a broadleaf evergreen tree with green foliage. In spring and summer orange flowers emerge. Attracts hummingbirds. Grows well with sun and low water. Drought tolerant once established. Adapts to various soil conditions. Does well in lean and well-drained soil. A good option if you're seeking something heat tolerant.

CHARACTERISTICS OF Grevillea robusta

Plant type: tree
Plant family: proteaceae
Foliage: evergreen green
Mature size: 20 FT - 35 FT - wide, 40 FT - 60 FT - tall
Flowers: orange blooms in spring and summer

GROWING CONDITIONS for Grevillea robusta

USDA Zones: 9a - 10b
Sun exposure: sun
Watering frequency: low
Resistant to: deer, heat
Soil needs: lean and well-drained

Nursery contributed plant descriptions

This beautiful 30-70' (or taller) evergreen tree from coastal Australia features beautiful and huge fern-like, dark-green leaves. As a member of the Protea family, it produces very interesting flowers. Large, showy clusters of bright golden-orange 'toothbrush' flowers appear in spring and are positively dripping with nectar! This nectar is edible, as is the gum that that this plant yields. This very adaptable and fast-growing tree a makes a showy shade tree or large hedge. Useful as a pollinator plant and also produces a powerfully deep golden dye. S/M-D/GDr
Largest of the Grevilleas, this tree from the rainforests of Queensland has distinct, divided, fernlike leaves. On mature trees, which may grow to 60' or more (100' has been recorded), inflorescences of large, orange flowers are produced in climates with sufficient summer warmth. Once a common plant in California landscapes, it has seemingly fallen into disfavor there and has now become remarkably scarce. But now you have the chance to join the minions of those who have killed this spectacular plant in the Pacific Northwest. A true 'zonal denial' plant, it is one of the fastest and easiest Grevilleas to grow, until we get nailed with a really cold winter which will certainly kill it outright. While it's really not hardy to our winters, I finally got one established and growing on my sixth attempt. You don't have to buy six of them though; I will just tell you what I did: grow it on in a pot until at least 5' tall, then plant it in a very sheltered spot in full sun with little frost, and don't water it too much. Hardy to about 25 °F for young plants, maybe as low as 15 to 20 °F when older, if you're lucky enough to see it get any size.

Gardening facts about Grevillea robusta plant

How to Grow Grevillea robusta

  • Sun Exposure

    • sun
  • Water Needs

    • low - drought tolerant
  • Soil Needs

    • adaptable
    • lean
    • well-drained
  • Special Situation

    • heat tolerant

Features

  • Foliage Color

    • green
  • Flower Color

    • orange
  • Wildlife

    • hummingbirds
    • deer resistant
  • Flower Season

    • spring
    • summer
  • Foliage Season

    • evergreen

Landscape groups by tags

See other plant types of Grevillea for your garden

aka Royal Grevillea

Plant Type

Shrub

Zones

7b-10b

Size

Height: 6'-8'

Width: 8'-10'

  • sun - dappled shade
  • regular - drought tolerant
  • dry in summer
Photo of Grevillea victoriae flower by J.G. in SF
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aka Grevillea victoriae 'Marshall Olbrich', Grevillea victoriae 'Marshall Olbricht', Grevillea victoriae 'Marshall's Seedling', Royal Grevillea

Plant Type

Shrub

Zones

7a-10b

Size

Height: 3'-6'

Width: 4'-6'

  • sun
  • regular - drought tolerant
  • dry in summer
Photo of Grevillea 'Marshall Olbricht' flower by Joshua McCullough
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aka Grevillea 'Canberra', Canberra Gem Spider Flower

Plant Type

Shrub

Zones

8b-11

Size

Height: 4'-9'

Width: 10'-12'

  • sun
  • occasional - drought tolerant
  • dry in summer
Photo of Grevillea 'Canberra Gem' foliage by Danger Garden
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aka Grevillea 'Ellendale Pool', Grevillea 'Ellendale', Spider Net Grevillea

Plant Type

Shrub

Zones

9a-10b

Size

Height: 3'-5'

Width: 3'-5'

  • sun
  • drought tolerant
  • dry in summer
Photo of Grevillea fililoba by Stan Shebs
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More Options

Plant Type

Shrub

Zones

8a-10b

Size

Height: 1'

Width: 4'-5'

  • sun
  • drought tolerant
  • dry in summer
Photo of Grevillea lanigera 'Coastal Gem' container plant by Far Out Flora
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+71 more Grevillea
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