Silky Oak

Grevillea robusta

Proteaceae · broadleaf evergreen tree · introduced

Last updated March 9, 2026

Quick Facts

Height

115 ft

Spread

49 ft

Growth Rate

Fast

Light

Full Sun

Soil

Adaptable

Water

Moderate

Hardiness

Zones 8a–8b

Bloom Time

Jun 15-Aug 15

Origin

Australia (Queensland and New South Wales); considered a

View full calendar (5 stages)

Stage	Typical Window	What to Look For
New growth flush BBCH 11	Feb 15-Mar 15	Lighter-colored new growth visible at branch tips
Bloom start BBCH 61	Jun 15-Aug 15	First open flowers visible; flowers yellow
Bloom end / petal fall BBCH 69	Jul 15-Aug 31	Last petals falling; flower structures fading
Fruit/seed development BBCH 71	Sep 1-Nov 30	Fruit or seed structures forming; fruit color: brown
Fruit/seed maturity BBCH 85	Dec 1-Feb 28	Fruit fully colored and ripened; seed dispersal may begin

Data Maturity

Baseline Extension data. Expert review underway.