A shrub, usually to about 4 m tall without a lignotuber.
It is found in restricted areas in the central coast, tablelands and central western slopes, mainly in the Blue Mountains (Wollemi National Park), on sandstone cliffs or steep rocky slopes. It grows in dry sclerophyll woodland and forests.
The leaves are whorled, somewhat stiff and leathery, elliptic to obovate, to 12 cm long and 4 cm wide with lobed to toothed margins. Olive to green to blue-green on upper surface and white on under surface, sometimes with yellow to rusty hairs on mid and secondary veins. This species can produce red-brown hairy new growth.
The inflorescences of banksias are generally referred to as spikes or a spike-like structure which consists of fused racemes of paired flowers (hence it gets referred to as a conflorescence). There can be 100s of flowers in each spike. The flowers of banksias have 4 tepals (petals or sepals) in a tubular formation, 4 anthers hidden inside and an elongated carpel (female part) where the style and extends outwards forming the edge of the spike (somewhat similar to individual grevillea and hakea flowers).
In this species, the spikes are generally to 19 cm long and up to 6 cm wide, with each flower thin but up to 3 cm long, yellow-green with green-blue colouring when in bud (a useful identification feature). At times, inflorescences can display other colours. They can also have a sweet smell.
The spike then turns into a cone-like structure of follicles; a fruit which splits open on one side. Each follicle has one or two winged seeds which is actually a fruit in itself called a samara. The follicles can take a long time to mature and open, usually needing a fire or a drying out period. Each “cone” can produce a fair amount of seed with this species having follicles to 15 mm long with over 100 follicles per “cone”.
Not as popular as other banksias, but known to be cultivated and is reported to be hardy (see references). It provides a nice architectural form with stiff leathery leaves. It is a very attractive architectural plant.
Plant in a sunny spot / dappled sun and allow for drainage. Many banksias benefit from growing on a slight slope. Do not mulch too heavily and try to keep grass away from the trunk. Very hardy once established. It is excellent for attracting honeyeater and other birds.
Will grow consistently if happy and will form a very nice shrub, to 3 m tall, but can be kept much more compact if pruned. May get sparse and leggy if not pruned. Very suitable for sandy gardens.
Suitable for small gardens.
Do not apply a high phosphorus fertiliser as Proteaceae are generally sensitive.
Prune after flowering or harvest cut flowers. Can be shaped into a denser bush if pruned early. Has some frost tolerance.
Susceptible to Phytophthora and any other root rotting fungus.
Propagation from seed is very reliable and not too difficult.
This species is very similar to Banksia oblongifolia and Banksia paludosa which also may also grow in the same habitat. B. penicillata is confined to cliffs and steep slopes in the Blue Mountains and so a location and habitat condition could be applied for identification.
B. oblongifolia has yellow to yellow-green inflorescences with the early buds tinged green-blue. Reportedly, B. paludosa does not produce the new red-brown growth of B. penicillata and has golden inflorescences.
This species can regenerate after fire from the seed bank. Does not exhibit a lignotuber.
Banksia – named in honour of Joseph Banks (1743 – 1820), famous naturalist and botanist on the Endeavour and other expeditions, and President of the Royal Society for over 40 years. The genus was named in his honour by Linnaeus filius (Carl von Lynne – the Younger, son of the famous Carl von Lynne (Linneaus)).
penicillata – Latin – referring to a tuft of hairs – much like an artist’s paint brush. Referring to the tufts of hairs on the bracts between the flowers in the inflorescence.
Not considered to be at risk in the wild. However, is considered rare and confined.