A tree capable of reaching 8 metres tall in the wild and a canopy spread to 5 m. It is found naturally on sand deposits (consolidated sand dunes) on the central and north coast of NSW (north from Sydney), extending into south-east Queensland.
It is common as a large shrub in coastal heath and shrublands. The common name comes from it growing on Wallum Sands. It is also found on relatively young sand deposits in western Sydney at Agnes Banks Reserve. The bark is warty and gnarled and the branchlets hairy.
The leaves are alternate to whorled, and with a leather, almost-plastic texture, oblong to narrow-obovate, to 20 cm long and 3 cm wide. The lower surface is much paler than the mid green upper surface. Both surfaces can have some rusty hairs. The conspicuous feature is the serrated leaf margin.
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 20 cm long and up to 10 cm wide, with each flower thin but up to 5 cm long, yellow to creamy-green in colour.
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. Each “cone” can produce a fair amount of seed with this species having up to 25 follicles.
Reported to be a relatively easy plant to grow in the right spot and on the right soil – sandy and free draining. It does not grow as big as other banksia and is considered more versatile but is harder to source.
Plant in a sunny spot with good drainage, on a slight slope works really well. Do not mulch too heavily and try to keep grass away from the trunk. Very hardy once established. It is excellent for attracting honey-eating birds.
Slow growing but will grow consistently if happy and will form a very nice shrub after a few years. Will likely grow to about 4 m in a garden (although this will take time) and tends to spread widely, so allow some space. Very suitable for sandy gardens.
Do not apply a high phosphorus fertiliser as Proteaceae are generally sensitive.
Prune after flowering or harvest cut flowers. Can be trained into a denser shape with periodic pruning.
Susceptible to Phytophthora and any other root rotting fungus.
Propagation from seed is very reliable and not too difficult.
Appears very morphologically similar to Banksia serrata. General differences are B. aemula is a smaller plant, with narrower leaves, and the leaves tend to form dense false-whorls underneath generally shorter flower spikes. The main difference is in the shape of the pollen presenter on the style; more cone-shaped in B. aemula and more narrow in B. serrata. The two species can grow together on sand dunes.
Can regenerate from seed bank after fire very readily as well as epicormic shoots and a lignotuber below ground.
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)).
aemula – from the Latin for “rival” or “competitor”, which is referring to its strong similarity to Banksia serrata.
Not considered to be at risk in the wild. Very common