Grevillea — Australian genus of flowering shrubs and trees

Description and botanical characteristics

Grevilleas display a wide variety of forms. Leaves may be simple or deeply divided, often tough and leathery, and many are adapted to dry, nutrient-poor soils. The flowers are usually arranged in dense clusters or racemes; individual flowers have long styles that extend beyond the perianth, which is why some species appear spider-like or toothbrush-shaped. Nectar produced by the flowers attracts a range of pollinators, particularly nectar-feeding birds such as honeyeaters, as well as insects.

Taxonomy, names and distribution

The genus belongs to the subfamily Grevilleoideae within Proteaceae and is closely related to genera such as Hakea. The name commemorates Charles Francis Greville. Grevilleas are most diverse in Australia but several species have restricted ranges in New Guinea, New Caledonia and Sulawesi. For general reference and species lists see Grevillea overview and specialist databases such as regional flora.

History and horticultural development

European botanists described many grevillea species in the 18th and 19th centuries as exploration of Australia increased. Horticulturally, grevilleas became popular for their flowers and wildlife value; many species interbreed easily and breeders have developed a wide range of hybrid cultivars. A well-known garden hybrid is Grevillea 'Robyn Gordon', admired for prolonged flowering. Several horticultural guides and plant societies provide cultivation advice: growing tips and cultivar lists are widely available.

Uses, cultivation and care

Grevilleas are grown for ornamental value, for attracting birds and for shelter in native plantings. One species, Grevillea robusta, commonly called silky oak, has been used as a timber and shade tree in some regions. Most grevilleas prefer sun to part shade, good drainage and soils low in phosphorus; they often perform poorly in heavy, waterlogged soils. Propagation is by seed or cuttings, and some grafted forms are used to improve tolerance to different soils. Gardeners should be aware that contact with some species can cause skin irritation in sensitive individuals.

Ecology, conservation and notable species

Ecologically, grevilleas provide nectar and habitat for birds, insects and small mammals. Several species are widespread and common in their native ranges, while others are restricted to small areas and are subject to threats such as habitat loss, invasive species and altered fire regimes. Conservation listings and recovery plans can be found via regional conservation agencies; see resources like conservation advice and species profiles such as notable species list.

• Grevillea robusta — timber and large ornamental in cultivation.
• Grevillea juniperina — a variable shrub often used in gardens.
• Grevillea 'Robyn Gordon' — an enduring hybrid favored for continuous blooms.
• Specialist sources and nurseries: plant breeding and hybrids.

For practical advice on selection, propagation and local species, consult regional horticultural societies and authoritative plant databases. Grevilleas remain a cornerstone of Australian native gardens and a subject of active cultivation and conservation interest worldwide.