Grevillea banksii

Red Silky Oak, Banks Grevillea, Byfield Waratah

Family: Proteaceae

A large shrub 7 m high. There are also prostrate forms found in the natural habitats. It is endemic to Queensland, occurring from Ipswich to Townsville, mainly along the coast in dry sclerophyll woodland and forest and coastal heathland, ridges and slopes.

Leaves are alternate along the stems, strongly divided (pinnatisect), with linear lobes, to 30 cm long and 10 cm wide. Green-silver, with the underside have a silvery-sheen due to 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 one of the cylindrical-bearing with racemes bright red to creamy-white, to 15 cm wide. Flowers all year but chiefly winter–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.

The perianths are creamy white to red-scarlet, crimson sometimes verging on apricot.
The carpels are to 50 mm long, red to creamy-white.

Follicles are to 25 mm long with sparse hairs.

In the garden

One of the most commonly cultivated grevillea, it has been in cultivation for a long time. These days, pure forms are not often planted but rather the numerous cultivars which have been created of which G. banksii is a parent. These cultivars include “Robyn Gordon”, “Misty Pink”, “Superb”, “Ned Kelly”, “Pink Surprise” and others. Separate profiles are available on the database for these other known cultivars.

Grows readily in a range of situations; it is very hardy. Can tolerate a variety of soils so long as drainage is adequate. Grow in full sun to part shade. Pruning will encourage flowering and they can be cut back very hard after a few season’s growth, if they get leggy. Can flower heavily and for extended periods.

A note of caution: there are alkaloids in the leaves that cause dermatitis in some people. Be cautious when pruning and apply all PPE.

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 the propagation of named cultivars.

Other information

This species was previously known as Grevillea buxifolia subsp. sphacelata
The common name “Grey Spider Flower” is applied to several grevilleas.

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 likely regenerates from seed.

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.

banksii – named by Robert Brown in honour of Joseph Banks (1743-1820), English naturalist, botanist and famous expeditioner who accompanied Captain Cook on his first circumnavigation (1768-1771).

Not considered at risk in the wild.

http://anpsa.org.au/g-ban.html 
https://en.wikipedia.org/wiki/Grevillea_banksii
https://profiles.ala.org.au/opus/foa/profile/Grevillea%20banksii

By Jeff Howes, edited by Dan Clarke