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Grevillea robusta (Silky Oak)

Silky Oak, Silk Oak, Silky-Bark Oak

AGM Award
Grevillea robusta, Silky Oak, Silk Oak, Silky-Bark Oak, Mediterranean shrubs, Evergreen Shrubs, Yellow flowers, Orange flowers, drought tolerant flowers
Grevillea robusta, Silky Oak, Silk Oak, Silky-Bark Oak, Mediterranean shrubs, Evergreen Shrubs, Yellow flowers, Orange flowers, drought tolerant flowers
Grevillea robusta, Silky Oak, Silk Oak, Silky-Bark Oak, Mediterranean shrubs, Evergreen Shrubs, Yellow flowers, Orange flowers, drought tolerant flowers
Grevillea robusta, Silky Oak, Silk Oak, Silky-Bark Oak, Mediterranean shrubs, Evergreen Shrubs, Yellow flowers, Orange flowers, drought tolerant flowers

Fast-growing and stately, Grevillea robusta (Silky Oak) is an evergreen tree of great beauty. Pyramidal when young, it develops a few horizontal limbs when older, giving it a broader top. Mature specimens produce a striking display of large, rich, bright golden orange flowers, up to 5 in. long (12 cm), in dense, one-sided spikes in spring-summer. Equally attractive is the foliage of olive-green, fern-like leaves, to 12 in. in length (30 cm), silvery underneath. Frost hardy to 16°F (-8°C), although it becomes semi-deciduous under those conditions, Silky Oak is often grown as an annual for the beauty of its foliage.

  • Recipient of the prestigious Award of Garden Merit of the Royal Horticultural Society
  • Grows up to 75 ft. tall (22 m) and 25 ft. wide (7.5 m).
  • Easily grown in acidic, well-drained soils in full sun. Drought tolerant once established. Use little to no phosphorus fertilizer.
  • Deer resistant
  • Great as a specimen plant in Mediterranean gardens and xeriscape gardens.
  • Virtually disease free and pest free.
  • Propagate by seed, semi-hardwood cuttings or graft.
  • Native to Australia

Requirements

Hardiness 10 - 12
Heat Zones 3 - 12
Climate Zones 8, 9, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, H1, H2
Plant Type Trees
Plant Family Proteaceae
Genus Grevillea
Common names Grevillea
Exposure Full Sun
Season of Interest Spring (Early, Mid, Late)
Summer (Early, Mid, Late)
Height 70' (21.3m)
Spread 20' - 25'
(6.1m - 7.6m)
Maintenance Low
Water Needs Low
Soil Type Loam, Sand
Soil pH Acid, Neutral
Soil Drainage Moist but Well-Drained, Well-Drained
Characteristics Plant of Merit, Showy, Evergreen
Native Plants Australia
Tolerance Drought, Deer
Attracts Birds, Butterflies, Hummingbirds
Garden Styles Mediterranean Garden
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Alternative Plants to Consider

Grevillea ‘Robyn Gordon’
Grevillea ‘Superb’
Grevillea ‘Peaches and Cream’
Grevillea rosmarinifolia (Rosemary Grevillea)
Grevillea ‘Moonlight’
Grevillea ‘Long John’

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Grevillea
While every effort has been made to describe these plants accurately, please keep in mind that height, bloom time, and color may differ in various climates. The description of these plants has been written based on numerous outside resources.
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Requirements

Hardiness 10 - 12
Heat Zones 3 - 12
Climate Zones 8, 9, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, H1, H2
Plant Type Trees
Plant Family Proteaceae
Genus Grevillea
Common names Grevillea
Exposure Full Sun
Season of Interest Spring (Early, Mid, Late)
Summer (Early, Mid, Late)
Height 70' (21.3m)
Spread 20' - 25'
(6.1m - 7.6m)
Maintenance Low
Water Needs Low
Soil Type Loam, Sand
Soil pH Acid, Neutral
Soil Drainage Moist but Well-Drained, Well-Drained
Characteristics Plant of Merit, Showy, Evergreen
Native Plants Australia
Tolerance Drought, Deer
Attracts Birds, Butterflies, Hummingbirds
Garden Styles Mediterranean Garden
How Many Plants
Do I Need?
Explore Great Plant Combination Ideas
Grevillea
Guides with
Grevillea
Not sure which Grevillea to pick?
Compare Now

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