Grevillea rosmarinifolia

Rosemary Grevillea

Family: Proteaceae

A shrub usually to 2 m tall. It is a native of NSW and Victoria, found in the central and southern areas of NSW, south from around Oberon, through the tablelands, slopes and the east of the western plains (as well as the south coast) into Victoria.

It grows naturally in woodlands near streams and on moist slopes, as well as in mallee habitats and shrublands. It is typically found on sandy soils.

It has become a serious garden escapee/weed of grasslands, open woodlands and rocky slopes in temperate and occasionally also cooler sub-tropical regions, especially in South Australia.

Leaves are alternate along the stems. elongated to very narrow (i.e. linear), to about 4 cm long and only 0.3 cm wide, have margins that are curled under (i.e. revolute), which partly or wholly conceal the lower leaf surface. Their upper surfaces are hairless and their lower surfaces are either loosely covered with some silver/grey silky hairs.

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 another of the spider-flowers. The inflorescences may be branched or unbranched, each branch bearing one to many flowers, bright red in colour, sometimes with cream tinges. Flowering occurs mainly during spring, but occasionally in late winter or early summer (i.e. from August to December).

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.
This carpels are red and hairless (i.e. glabrous) or only slightly hairy (i.e. puberulent) and swollen near its tip. The perianth is also red, sometimes with cream tinges at the top

The fruit is a follicle, usually hairy, turning from green to brown in colour as it matures. When fully mature it splits open to release its seeds.

In the garden

This was one of the first Grevilleas that many gardens grew as an introduction to native plants as it is a hardy shrub for temperate climates in well drained soils and full sun to partial shade.

Has dense prickly foliage excellent refuge for small birds, including finches and wrens. Nectar-rich flowers attract native birds, moths, butterflies and other insects.

It needed to be pruned regularly to prevent the plant becoming ‘leggy’ and unsightly. When this happens, it is best to be removed and new plants installed with some soil improvement.

Please note: Grevillea rosmarinifolia subsp. rosmarinifolia is regarded as an environmental weed in South Australia, the ACT, and those parts of Victoria outside its native range. It forms dense clumps that can smother patches of native grassland and take over the shrub layer of open woodlands. So plant with caution if adjoining or near native bushland areas.

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

There are two currently recognised subspecies:
Grevillea rosmarinifolia subsp. glabella: prickly leaves, narrow, shorter and crowded.
Grevillea rosmarinifolia subsp. rosmarinifolia: wider leaves, less prickly, longer and less crowded

There is a popular cultivar available called ‘Scarlet Sprite’.

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.

An additional note for Grevillea rosmarinifolia has been the rediscovery of the type form (the ‘type form’ is the form originally collected and described). The type form of G. rosmarinifolia was collected on the Coxs River near Bathurst by Allan Cunningham in the early 1800s but was subsequently believed to be extinct in that area. In 1969, this form was actually discovered growing in the Edinburgh Botanic Gardens, no doubt derived from material sent back to the UK by Cunningham. Subsequently, a search in the original location on the Coxs River rediscovered this form in its natural habitat.

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.
rosmarinifolia – Latin – having leaves similar to the genus Rosmarinus, the Rosemary plant. (although in recent times, Rosemary has been renamed Salvia rosmarinus).

Not considered at risk in the wild and has weedy tendencies in some areas.

https://en.wikipedia.org/wiki/Grevillea
https://keyserver.lucidcentral.org/weeds/data/media/Html/grevillea_rosmarinifolia_subsp._rosmarinifolia.htm
https://www.gardeningwithangus.com.au/grevillea-rosmarinifolia-scarlet-sprite-grevillea/

By Jeff Howes, edited Dan Clarke