What is a hairpin banksia?
The hairpin banksia is a shrub native to the east coast of Australia. Hairpin banksias are a relatively short plant ranging between one to three metres in height. The Darug word for banksia is wadanggari.
During autumn and winter hairpin banksias feature large cylindrical flower spikes ranging from 10 to 20 centimetres long. The flowers can be brown, red, orange or gold. The leaves of the hairpin banksia are long – three to eight centimetres in length – but narrow – two to seven millimetres wide. The trunks have smooth, grey-brown bark. There are three different varieties of hairpin banksias, each differing in height and leaf shape.
The scientific name for the hairpin banksia is Banksia spinulosa. Banksia commemorates Sir Joseph Banks, the botanist who travelled with James Cook on his first Pacific voyage. Spinulosa, meaning small spines, refers to the bluntly pointed tips of leaves. Hairpin banksias are not so spiky and so are not painful to touch.
Where are hairpin banksias found?
Hairpin banksias grow in sandy soils which are moist but drain easily. They are found in dry sclerophyll forests and woodlands between the eastern coastline and the Great Dividing Range.
What eats hairpin banksias?
Like other banksias, the flowers of the hairpin banksia produce a large amount of nectar. The nectar attracts many native nectar-feeding bird species such as honeyeaters and spinebills and small mammals such as antechinuses and ring-tail possums.
What adaptations do hairpin banksias have to their environment?
Hairpin banksias are well adapted to the soils in which they grow. They have special proteid roots – roots with lots of small rootlets – that are efficient at absorbing the low levels of water and nutrients that are available in the soil. Their leaves are narrow, hard and woody meaning they do not require a lot of water or nutrients to grow.
Like other banksias, hairpin banksias are well adapted to surviving fire events. After fire, leaves resprout from special ‘back up’ buds called epicormic buds found beneath the bark of the trunk. Hairpin banksias have woody enclosed fruits which protect their seeds from fire as well as foraging animals. Some varieties of hairpin banksias have lignotubers which are woody swellings at the base of the plant which contain buds which sprout when the stem above ground is killed.
How do hairpin banksias reproduce?
Hairpin banksias rely on pollinators for their reproduction. Native bees, birds such as spinebills and honeyeaters, and small mammals, such as brown antechinuses and ring-tail possums, help transfer pollen between the flowers of different trees.
When the banksia flowers are pollinated they form woody seed pods called a follicle.
Hairpin banksias keep their seeds in follicles until they are burnt. During a bushfire the seeds drop to the ground and germinate in ash-rich soil clear from other plants which would otherwise compete for sunlight and water. Because of the relationship between fire and seed release it is important to prevent bushfires from becoming too frequent so that the new seedlings have an opportunity to grow into adults and produce seeds of their own.
Hairpin banksias are not completely reliant on fire for reproduction. In the absence of fire the follicles also release seeds to the ground when they become very dry or when other parts of the tree are dying.
How are hairpin banksias used by Aboriginal Peoples?
Hairpin banksias are a source of food for Darug Peoples. The sweet-tasting nectar can be eaten by directly sucking it from the flower or soaking the fresh banksia flower in water to make a sweet drink.
