Grevillea wilkinsonii is a bushy shrub that may reach a height of 2 metres by up to 1 metre wide.
It is a rare grevillea in the wild, only known from 2 populations in NSW; one is along the Goobarragandra River (20 km east of Tumut, where about 1000 plants have been observed); the other is on private property at Gundagai (where less than 10 plants exist). It grows in dry sclerophyll eucalypt woodland on riparian loam soils and serpentinite rock.
The leaves are up to 17 centimetres long, and to 2.5 centimetres wide, dark green above and silvery-white below with toothed margins that end in short spines.
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 a tooth-brush type with brownish-pink to red-purple inflorescences appearing predominantly from October to November. Each “tooth-brush” is up to 5 cm long by 2 cm wide.
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 up to 1 cm long; brownish-pink through to red-purple.
The carpels are up to 3 cm long, red to lilac in colour, and tipped with a yellow pollen-presenter.
The fruit is a follicle, with some hairs and reddish blotches.
Grevillea wilkinsonii has proved to be very hardy in cultivation and will tolerate drought and frost. It has not been cultivated for long (as it was only discovered in the 1990s). If plants could be sourced from nurseries, it is well worth growing.
A light pruning, after flowering, will encourage new growth and abundant flowering.
The toothbrush-shaped flower-heads are an unusual purplish-pink. Blooms are both conspicuous and profuse. Both foliage and flowers are attractive features.
Grevillea wilkinsonii could be cultivated as a “stand alone” specimen and in native shrubberies. Useful for attracting birds.
Propagation from cuttings is reasonably rapid.
Ripe seeds are collected by ants. Multiple seedlings have been observed growing out of ant nests. In our cold climate garden, ants play a role in the dispersal of other Grevilleas and Acacias.
In the plant description, published in Telopea (the journal of the Sydney Royal Botanic Gardens) a grader driver (name unknown) is mentioned in the acknowledgements. During roadworks he listened to pleas to avoid one of the Grevillea wilkinsonii populations.
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.
wilkinsonii – named after Tom Wilkinson who discovered the species, by Bob Makinson in 1993.
The species is listed as threatened with extinction in the wild, at the State and Commonwealth level with the categories of critically endangered and endangered respectively.
NSW Flora Online (PlantNET) – Grevillea wilkinsonii profile page https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Grevillea%7Ewilkinsonii
NSW Office of Environment and Heritage – Threatened Species Profiles – Grevillea wilkinsonii https://www.environment.nsw.gov.au/threatenedspeciesapp/profile.aspx?id=10381
Australian Native Plants Society Australia – Grevillea wilkinsonii profile page https://anpsa.org.au/plant_profiles/grevillea-wilkinsonii