Banksia praemorsa

Cut-leaf Banksia

Family: Proteaceae

A shrub, usually to about 4 m tall. It is restricted to south-west WA on the south coast between near Albany and extending about 100 km east. It grows on sand in sclerophylls shrubland and woodland.

The leaves are alternate to pseudo-whorled, somewhat stiff and leathery, elliptic to obovate, to 5 cm long and 1.5 cm wide with toothed to entire margins and a squared-off (truncate) apex for which the common and species names come are given. Dark green to blue-green on upper surface and paler on under-surface.

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 35 cm long and up to 10 cm wide, with each flower thin but up to 5 cm long, dark-red/pink or yellow in colour with the stigmas tipped cream, creating a very attractive plant.

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.
Known to be cultivated and is reported to be hardy (see references). It provides a nice architectural form with stiff leathery leaves. The inflorescence colour is unusual, being described as dark red-pink to red-purple but sometimes yellow in then tinged with pale yellow when flowers begin to open. The inflorescences can also be 35 cm long – adding to the attraction.



In the garden

Will grow consistently if happy and will form a very nice shrub, reaching 5 x 3 metres, so allow some room. But can be kept much more compact if pruned. May get sparse and leggy if not pruned.

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. Has some frost tolerance. May not tolerate high humidity but is reported to be hardy in humid conditions.

Very suitable for sandy and coastal 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.

Susceptible to Phytophthora and any other root rotting fungus.

Propagation

Propagation from seed is very reliable and not too difficult.

Other information

This species can regenerate after fire from the seed bank. It does not have 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)).
praemorsa – Latin – reportedly meaning “appears to have been bitten off” referring to the cut-off leaf tips of the species.

Not considered to be at risk in the wild. However, is considered rare and confined.

http://anpsa.org.au/b-pra.html
https://www.gardeningwithangus.com.au/banksia-praemorsa-cut-leaf-banksia/
https://en.wikipedia.org/wiki/Banksia_praemorsa

By Dan Clarke