Grevillea triternata is an often straggly shrub reaching a height of 1.5 metres.
It is found on the Coast, Tablelands and Slopes of NSW, growing from west of Dapto, south to Berrima-area, west to Orange-area and north-west to Warrumbungles National Park, extending north along the western slopes and tablelands to close to the border with Queensland.
Light green leaves are strongly divided (pinnatisect) into two or three primary segments with each segment also having up to three secondary segments (there may rarely be tertiary segments as well). Each primary segment can have 3 to 5 divisions with secondary segments ending in either 1, 2 or 3 “prongs” or sharp linear to triangular points. This makes for interesting, if prickly, foliage.
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 has cylindrical-inflorescences, although they are small, up to 3 cm long and 1 cm wide, white to cream or pale green inflorescences, appearing mainly in winter to spring.
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. In this species, the perianth is very small, up to 5 mm long; cream to white to pale green, without hairs.
The carpels are up to 6 mm long, white to cream to pale green.
The fruit is a follicle, with reddish brown striped or blotches.
This is not the most spectacular grevillea and is not all that commonly grown. Because of the dense, prickly foliage Grevillea triternata would be a useful addition to a bird-friendly garden. The foliage provides safe nesting sites and is an interesting feature.
The straggly growth habit may be slightly modified by tip pruning.
Grow in full sun to part sun, in a well-draining soil, for best results.
Propagate from cuttings.
The type was collected in Port Jackson, Sydney in 1817 and named in 1830.
G. ramosissima is similar but differs in the size of the leaf segments.
Grevillea is a diverse genus of about 360 species of evergreen flowering plants native to rainforest and more open habitats in Australia, New Guinea, New Caledonia, Sulawesi and other Indonesian islands east of the Wallace Line. NSW currently has about 85 species although with a lot of subspecies and some informal taxa recognised.
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 copping shoots.
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.
triternata – Latin – meaning triternate – a condition where a leaf is divided into 3 groups of 3 leaflets. This can be seen in a native plant such as Clematis microphylla.
NSW Flora Online (PlantNET) – Grevillea triternata profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Grevillea~triternata
Plants of South Eastern New South Wales – Grevillea triternata profile page https://apps.lucidcentral.org/plants_se_nsw/text/entities/grevillea_triternata.htm