Grevillea insignis

Wax Grevillea

Family: Proteaceae

A shrub growing to 5 metres tall with spreading/arching branches which can spread several metres wide.

It grows naturally in the south-west of Western Australia, on gravelley sand or loam with ironstone influence.

Leaves are green-blue (glaucous) with a holly-shape, to about 60 mm long by 40 mm wide with shallow and prickly lobes on the margins. The new growth has bronze-red tinges.

A grevillea inflorescence is technically a cluster of paired flowers, termed a conflorescence with the overall structure forming a raceme-like appearance. Grevillea species exhibit 3 main inflorescence structures:
– 1. A cylindrical to ovoid raceme (with flowers emerging around a 360° radius)
– 2. A single-sided raceme (with flowers produced on only one side, resembling a tooth-brush)
– 3. A condensed or clustered raceme (usually as long as it is wide, with species referred to as the spider-flowers)

Grevillea mostly produce the inflorescences at the terminals, beyond the foliage, which differs to the closely related Hakea.

This species is one of the spider-flowers, with inflorescences to about 3 cm long by 3 cm wide. They are bright pale pink, cream and red (reportedly starting more cream and turning pink) and can be produced profusely mainly in spring to summer.

Individual flowers are composed of 1 carpel (female part) where the style and stigma protrude out; 4 stamens hidden away in the perianth; and the perianth (petals and sepals collectively) which connects to a pedicel. Proteaceae flowers do not have any discernible petals or sepals (having only one whorl) and so these are referred to as “tepals” of which there are 4.

The carpels are to 30 mm long, dark red with red tips. The perianths are pale-pink and cream with older flowers turning more pink.

In the garden

A grevillea that is well-worth growing for its flowers, foliage colour and shape, and architectural form. Reported observations are also that the sunlight on the foliage creates a beautiful effect.
They are grown at Joseph Banks Native Gardens, Kareela and at other botanic gardens readily. Can be shaped to a dense symmetrical shrub of 2 x 2 metres and such plants are very attractive. Can grow to 5 metres tall but can be top-pruned if needed.

It may be slow growing to start with. A fast-draining sandy soil is likely essential for it to do its best. Full sun to part shade. It is excellent for attracting bees and other insects. Will tolerate light frost.
Some forms are now sold as grafted plants so check with your nursery.

Propagation

Grevilleas are propagated by three principal methods; seed, cuttings and grafting. To maintain desirable characteristics of a particular plant, vegetative propagation (e.g. cuttings or grafting) must be used. This also applies to propagation of named cultivars. Grafted forms are the best for east coast gardens.

Other information

Grevillea flowers were a traditional favourite among First Nations Peoples for their sweet nectar. This could be shaken onto the hand to enjoy, or into a coolamon with a little water to make a sweet drink. They might be referred to as the original “bush lollies”.

Grevillea – was named in honour of Charles Francis Greville (1749-1809), an 18th-century patron of botany and co-founder of the Royal Horticultural Society. He was also a British antiquarian, collector and politician who sat in the House of Commons from 1774 to 1790.

insignis – Latin for “remarkable”, “distinctive”, referring to the overall striking appearance of this species; its foliage and flowers.

http://malleedesign.com.au/just-because-its-beautiful-grevillea-insignis/
Wrigley, J.W. & Fagg, M.I. (2001). Australian Native Plants – Propagation, cultivation and use in landscaping. 4th edition. New Holland Publishers, Pty. Ltd. Australia.
https://florabase.dpaw.wa.gov.au/browse/profile/2021

By Dan Clarke