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Grevillea robusta

Grevillea robusta, Proteaceae

Sources last read 14 September 2026.

Not yet rated How forgiving it is has not been judged here yet.

Also called silk oak, silky-bark oak and Southern Silky-oak.

Grevillea robusta (Grevillea robusta), the whole plant.
Bageense, CC BY-SA 4.0 · Wikimedia Commons

Grevillea robusta is toxic

  • Not assessed for cats. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
  • Not assessed for dogs. This plant is not on the ASPCA list. That is not a finding of safety: none of the sources read for this site gives an answer either way. Treat it as unknown.
  • Toxic to people. Irritates skin and can cause skin allergy. Use gloves and protective gear when handling it. RHS

What the sources say about its care

Sources file this plant under other names: Grevillea robusta AGM. Citations below point at the name its source uses.

Light
Full sun
RHS · read 13 September 2026
Water
Moist but well-drained or Well-drained
RHS · read 13 September 2026
Humidity

No source read publishes a humidity figure for any plant on this site. What follows is general guidance for foliage plants.

ASHRAE recommends indoor relative humidity between 30% and 60% 30–60%
Penn State Extension · read 13 September 2026
Temperature

How cold this tolerates, not what it prefers. No source read for this site publishes a preferred range for a plant indoors.

H2 — 1–5°C 1–5 °C
RHS · read 13 September 2026
Soil
Loam, Sand; pH Acid or Neutral
RHS · read 13 September 2026
Toxic to cats
Not on the ASPCA list. That is not a finding of safety.
ASPCA · read 13 September 2026
Toxic to dogs
Not on the ASPCA list. That is not a finding of safety.
ASPCA · read 13 September 2026
Harmful to people
Irritates skin and can cause skin allergy. Use gloves and protective gear when handling it.
RHS · read 13 September 2026

Routine care

Propagation
Increase from seed, semi-hardwood cuttings or grafting.
RHS · read 13 September 2026
Pruning
Pruning group 1 outside; indoors, harder pruning may be needed to limit size.
RHS · read 13 September 2026
Pests and diseases
Usually free of pests. Diseases: honey fungus can occur, though rarely.
RHS · read 13 September 2026

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Close view of Grevillea robusta (Grevillea robusta) foliage.
Close upBageense, CC BY-SA 4.0 · Wikimedia Commons

About the plant

Grevillea robusta, commonly known as the southern silky oak, silk oak or silky oak, silver oak or Australian silver oak, is a species of flowering plant in the family Proteaceae and is endemic to eastern Australia. It is a tree with deeply dissected, divided leaves, golden yellow to orange flowers with red blotches and flattened, elliptic to oval fruit.

From Wikipedia, CC BY-SA 4.0 · read 13 September 2026

Native range
SE. Queensland to NE. New South Wales
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
E Australia
RHS · read 13 September 2026
Climate
subtropical
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Growth form
tree
World Checklist of Vascular Plants, June 2026 release, CC BY.
Kew WCVP · read 13 September 2026
Bushy (evergreen)
RHS · read 13 September 2026
Size
Height Higher than 12 metres; spread 4-8 metres after 20–50 years
RHS · read 13 September 2026
Flowering
Flowers yellow in spring and summer
RHS · read 13 September 2026

Plants with similar care

Sources

What this does not cover

The figures above are what published sources say, not measurements of the plant in your room. They say nothing about your pot size, your water, the season, or how far from the glass the plant stands, and those decide more than any figure here does.

Humidity has no species figure because no source read for this site publishes one, and the only temperature published for this plant is a cold floor. The simulator fills those gaps with general figures for its kind of plant, marked as general and listed on how we read sources. Where a toxicity row says the plant was not assessed, that is the absence of a finding and not a finding of safety.

If something is already wrong, the diagnosis tool asks about the soil, the window and the watering, which is where the answer usually is.