Caley’s Grevillea

Plants > Proteaceae

AT A GLANCE
Common Name: Caley’s Grevillea
Scientific Name: Grevillea caleyi
Category: Plants
Subcategory: Proteaceae
Size: Shrub height: 4–13 ft (1.2–4.0 m); Width: 6–15 ft (2–4.5 m)
Weight: Woody shrub biomass: 30–80 lb (15–35 kg)
Lifespan: 12–25 years in fire-managed bushland
Diet: Autotroph (photosynthetic; specialized proteoid roots for phosphorus uptake)
Habitat: Lateritic ridgetop soils in open scribbly gum and red bloodwood woodland
Range: Highly restricted endemic to Sydney’s Northern Beaches plateau, NSW
Conservation Status: Critically Endangered (IUCN Red List; listed as Endangered under EPBC Act)

Overview

Caley’s Grevillea (Grevillea caleyi) is an iconic, critically endangered flowering shrub endemic to a tiny pocket of remnant lateritic ridges in northern Sydney. Celebrated for its spectacular one-sided ‘toothbrush’ inflorescences of deep crimson and maroon, this striking member of the Proteaceae family depends intimately on periodic bushfires to stimulate seed germination and renew its wild population.

Biology and Physical Characteristics

Grevillea caleyi is a spreading, open shrub with arching branches reaching up to four meters tall. Its deeply pinnatifid leaves measure 7 to 18 cm long with soft, hairy lobes that feel velvety to the touch. During its prolonged flowering season from August to December, it produces horizontal, one-sided racemes resembling toothbrushes, adorned with dozens of individual rich red flowers featuring pale green styles tipped with dark maroon stigmas that release copious, sugar-rich nectar.

Behavior and Ecology

The nectar-laden blossoms of Caley’s grevillea serve as an essential carbohydrate source for native honeyeaters (such as the New Holland honeyeater and Eastern spinebill) and lorikeets, which act as primary pollen vectors. The plant produces large woody follicles containing two seeds equipped with nutrient-rich elaiosomes; native ants collect the fallen seeds and bury them underground in subterranean nests, safeguarding the soil seed bank from surface fire heat and granivorous rodents.

Conservation and Human Impact

With an estimated wild population of fewer than 2,000 mature plants, Grevillea caleyi is classified as Critically Endangered. Over 85% of its historical laterite habitat has been destroyed by residential housing developments, road widening, and infrastructure clearing in suburban Sydney. Remaining roadside fragments face weed invasion and altered fire regimes; ecological prescribed burns and community-led seed banking at the Australian Botanic Garden Mount Annan are vital to its survival.

Interesting Factoid

Caley’s Grevillea relies on native bush ants as underground caretakers: the ants carry its seeds into their subterranean chambers to eat the fatty appendages, planting the seeds in secure, natural germination chambers safe from predators.

Last updated: October 2026