SelecTree: Tree Detail

SILK OAK TREE
Grevillea robusta

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Photo Locations: Strybing Arboretum - San Francisco, CA, Los Angeles County Arboretum - Arcadia, CA, Cal Poly Campus - San Luis Obispo, CA and Lotusland - Santa Barbara, CA

General Notes

Requires a moderate amount of water. Blooms in spring. Grows to 150 feet high in the wild. Hardy to 24 degrees F.

Native to the Eastern coast of Australia.

Family: Proteaceae

Tree Characteristics

Erect and requires ample growing space.

Conical or Oval Shape.

Has Evergreen foliage.

Height: 50 - 65 feet.

Growth Rate: 36 or More Inches per Year.

Longevity 50 to 150 years.

Leaves Pinnately Compound Even with Lanceolate Leaflets, Medium to Light Green, No Change, Evergreen.

Flowers Showy. Orange or Yellow. Flowers in Spring. Has perfect flowers (male and female parts in each flower).

Brown Podlike with Winged Follicles, Medium (0.50 - 1.50 inches), fruiting in Fall.

Bark Dark Brown, Furrowed.

Shading Capacity Rated as Dense in Leaf.

Litter Issue is Dry Fruit, Leaves and Twigs.

Tree Site Conditions & Constraints

Sunset Zones 8, 9 and 12 - 24.

USDA Hardiness Zones 8 - 10.

Exposure Full Sun.

Moist to Dry Soil.

Drought tolerant.

Clay, Loam or Sand Texture.

Slightly Acidic to Highly Alkaline Soil pH.

Salinity Tolerance is Moderate on Coast.

Seaside Tolerance is Good in Mild Zone.

Pests & Disease Information

Susceptible to Scales, Phytophthora and Root Rot.

Health, Safety & Environmental Concerns

Branch Strength Rated as Weak.

Root Damage Potential Rated as Moderate.

Irritant Health Hazard.

Attracts Birds and Bees.

Not Deer Palatable.

Special Uses & Values

Hedged.

Cite this tree:
SelecTree. "Grevillea robusta Tree Record." 1995-2017. Mar 28, 2017.
< http://selectree.calpoly.edu/tree-detail/grevillea-robusta >

This tree is not part of the SelecTree Nursery Connection. If you would like to see this tree listed, or know of a nursery that sells it, please contact us at ufei@calpoly.edu.