Grevillea imberbis

Family: Proteaceae

A shrub to 0.4 m high or prostrate, with a rhizomatous suckering ability.

It is only found in two separate areas, from Kanangra Walls (Boyd Plateau) SE of Oberon and the Braidwood–Mongarlowe–Currockbilly areas (central and southern tablelands) in NSW. It grows in wet low heath or on heathy-woodland margins, in skeletal soils over sandstone.

Leaves are alternate along the stems, to 4 cm long and to about 0.7 cm wide, with an oblanceolate, linear to elliptic shape.

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 white to pale pink inflorescences. Flowering occurs from August to February.

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 perianth is white to pink, hairy outside, mostly hairless inside.
The carpels are to 9 mm long and have a pink to white tinge.

No information is available for the follicle. The rhizomatous growth habit may mean they are seldom produced.

In the garden

Very little is known about this species and there are very few online resources. It is likely that this plant is yet to be cultivated.
May grow well in a sandy soil if plants can be sourced.
In a garden situation, Grevilleas are good bird-attracting plants.

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.

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”.

Most Grevillea species will regenerate from seed after fire but can produce coppicing shoots. This species has a rhizomatous habit and so can likely regenerate using that mechanism.

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.

imberbis – Latin meaning ‘without spines or beard’, referring to the lack of hairs on the inside of the perianth (when compared to similar species).

Not known to be at risk in the wild. But grows in restricted areas.

https://en.wikipedia.org/wiki/Grevillea
https://apps.lucidcentral.org/plants_se_nsw/text/entities/grevillea_imberbis.htm
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Grevillea~imberbi

By Jeff Howes, edited by Dan Clarke