Banksia integrifolia

Coast Banksia

Family: Proteaceae

A shrub to tree, growing to potentially 25 m with tessellated or fissured bark. It is found only on sandy soils, close to the beach on the coast as well as some inland sandy environments (eg: Warkworth Sands Woodland in the Hunter Valley). The species grows along the entire NSW coast, and into the tablelands extending in the north to the north western plains. Extends into Victoria and Queensland. It is found in dry sclerophyll woodland, and heathlands and shrublands, on sandy soils / sand dunes, usually geologically recently deposited.

The leaves are consistently whorled (coming off the branch at one point in a 360° radius), to 20 cm long and 3.5 cm wide, narrow obovate to narrow elliptic, olive to mid green / blue-green above, white-hairy underneath. The leaf margin is usually entire but can have some short teeth on occasion.

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 12 cm long and up to 5 cm wide, with each flower thin but up to 2.5 cm long, bright yellow to pale yellow and can be produced in large number.

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. Spent “cones” are typically seen lying at the base of these trees.

In the garden

A popular plant in the garden and landscaping, especially in coastal environments. Does best on sandy soils and is used as council street trees in beachside areas and landscapes.

Plant in a sunny spot 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 tree after a few years. However, some plants may get leggy and so astute pruning may be needed to bush-up small plants. Will likely grow to about 10 m in a garden (although this will take time) and may spread to about 4 m wide, 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. Likely not overly frost tolerant. Very tolerant to coastal salt spray.

Susceptible to Phytophthora and any other root rotting fungus.

Propagation

Propagation from seed is very reliable and not too difficult.

Other information

A variable species across its range, plants in the north-west part of NSW have wider and more-toothed leaves
There is a cultivar available called ‘Roller Coaster’ (see references). It is a prostrate form and grows to about 15 cm tall, spreading horizontally. It creates a nice spill-over / groundcover.

This species can regenerate after fire from the seed bank or from epicormic shoots after fire.

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)).
integrifolia – Latin referring to the intact (untoothed) margin of the leaves. This species has leaves with entire margins which distinguishes it from other banksias.

Not considered to be at risk in the wild. Very common

https://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Banksia~integrifolia https://www.australianplantsonline.com.au/banksia-integrifolia-coastal-banksia.html
https://www.gardeningwithangus.com.au/banksia-integrifolia-coast-banksia/
https://www.gardeningwithangus.com.au/banksia-integrifolia-roller-coaster-banksia/

By Dan Clarke