Grevillea rivularis

Carrington Falls Grevillea

Family: Proteaceae

A shrub to 2.5 m high. It is confined to the Carrington Falls area on the upper Kangaroo River, west of Kiama, within Budderoo National Park in N.S.W.

It grows mainly on moist creek-sides on sandstone, in open heath or eucalypt woodland. It is listed as threatened with extinction.

Leaves are alternate along the stems, to 6 cm long. However, they are strongly divided with secondary or occasionally tertiary divisions, with 3 to 9 primary lobes each with 3 to 5 divaricate (splitting) secondary lobes, ultimate lobes linear to very narrow-triangular, to 3 cm long and to 0.3 mm wide, pungent with mucrones at the leaf tips.

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 “tooth-brush” type, appearing between September and April. The inflorescences are a mixture of pink / purple-pink and green.

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 perianths are translucent cream to purple-pink or mauve.

The carpels are pale pink with green tips.

The fruit is a follicle, hairy with reddish brown stripes or blotches.

In the garden

Despite its threatened status in the wild, it is cultivated and is available at several nurseries – well afar from its natural occurrence including overseas.

It is a hardy vigorous spreading shrub with attractive much-divided leaves, and attractive flowers. Grows in full sun to part-shade. Likely needs a well-drained sandy soil to do its best. It does grow naturally in moist areas so some watering in dry times may be needed. Can take a cold climate though may suffer from extended frost periods.

The foliage is an additional attraction here as well as the flowers.

An excellent tall and dense ground cover or screen plant.

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 is likely adverse to fire.

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.

rivularis – Latin for “inhabits small brooks or rivulets” due to its occurrence growing besides watercourses.

Listed as threatened:
Conservation status in NSW: Critically Endangered
Commonwealth status: Endangered

https://en.wikipedia.org/wiki/Grevillea
https://www.environment.nsw.gov.au/threatenedSpeciesApp/profile.aspx?id=10378
https://en.wikipedia.org/wiki/Grevillea_rivularis
https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Grevillea~rivularis

By Jeff Howes, edited Dan Clarke