Banksia - Australian Plant Information

The genus Banksia

There are 173 Banksia species, and all but one occur naturally only in Australia. Banksias were named after Sir Joseph Banks (1743-1820 ), who, in 1770, was the first European to collect specimens of these plants.

In recent years the genus Dryandra has been incorporated into the genus Banksia [more]

A number of Banksia cultivars have also been developed.

Where do they Occur?

South western Australia contains the greatest diversity of banksias, with 60 species recorded. They are also an important part of the flora of Australia's eastern coast. Few banksias are found in the arid regions of Australia or in the rainforests of the eastern coast.

There are no species which are common to eastern and western Australia except Tropical Banksia, Banksia dentata , which occurs across northern Australia, in Papua New Guinea, Irian Jaya and the Aru Islands.

Banksia Flowers and Fruits

The flower heads are made up of hundreds (sometimes thousands) of tiny individual flowers grouped together in pairs. The colour of the flower heads usually ranges from yellow to red. Many species flower over autumn and winter.
The fruits of banksias (called follicles) are hard and woody and are often grouped together to resemble cones (which they are not true cones are produced only by conifers).
The fruits protect the seeds from foraging animals and from fire. In many species the fruits will not open until they have been burnt or completely dried out.

Banksia serrata illustration
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Growing Banksias from Seed

Banksias are easily propagated from seed. A common way to release seed is to place the 'cone' in an oven at 120°140° C for about an hour. The follicles then open and the seeds can be removed with tweezers. Two black winged seeds are usually found in each follicle, together with a structure called a separator.
Insects sometimes lay their eggs in the flower buds and the larvae may eat the seed as it develops. A small hole in the woody fruit is usually a sign that this has happened and that the seed will not germinate.
Seeds should be sown in a very freely draining seed-raising mix which should not be allowed to dry out. As Banksia seedlings are prone to fungal attack, it is better to sterilise the seed-raising mix before planting. If this is not practical, very clean ingredients should be used.
Seedlings should be transplanted into small pots as soon as the first true leaves appear. A potting mix made from equal parts of river sand, loam and leaf mould (or peat moss) is generally suitable.

Rare and Threatened Banksias

Despite being such a popular Australian plant, several banksias are listed as rare or threatened.
Banksia brownii , the Feather-leaved Banksia, is named after the famous botanist Robert Brown (1773-1858) who accompanied Matthew Flinders to Australia. It is restricted to a few locations between Albany and the Stirling Ranges in Western Australia. [Colour photo.]
Banksia verticillata, the Granite Banksia, is restricted to a few sites on or beside granite outcrops from Albany to Two Peoples Bay in Western Australia. [ Colour photo.]

Banksias for the Garden

Banksias usually grow best in well drained soils in a sunny position. Most respond to light pruning, and those which form a woody rootstock (lignotuber) can be heavily pruned. Only low phosphorus fertilisers should be used.
Species native to Western Australia are prone to root-rot fungus and generally do not grow well in parts of Australia which experience high humidity and rainfall in the summer.
Banksias range from low-growing shrubs to trees up to 25 m tall. Some species, for example Banksia ericifolia and Banksia menziesii , are known for their spectacular flower heads. The flower heads produce large volumes of nectar and attract many birds and small mammals to feed on them. Banksias are excellent plants to encourage native animals to the garden.

Commonly Grown Banksias

The following Banksias grow well in most of the temperate areas of Australia and have been successful at the Australian National Botanic Gardens in Canberra. Most of these species are available commercially. The local branch of the Society for Growing Australian Plants may be able to assist in locating seed or cuttings of less commonly cultivated species.

Banksia aemula - Wallum Banksia

This plant is similar to the better known Banksia serrata . It rarely exceeds 3 m high, is more bushy in habit and is more tolerant of poorly drained soils. It was introduced into cultivation in England in 1788 and was among the first banksias to be grown there.

Banksia 'Giant Candles'

This cultivar grows as a medium to small shrub to 5 m high. It is probably a hybrid between Banksia ericifolia and Banksia spinulosa var. collina . The deep orange flower heads open over autumn and winter and can grow to 40 cm long. Plants prefer a well-drained site in full sun and are frost tolerant. Banksia 'Giant Candles' must be propagated from cuttings.

Banksia ericifolia var. ericifolia - Heath Banksia

This adaptable Banksia forms an excellent screen plant and is able to tolerate frost and salt spray. Plants may grow to 5 m tall, but are frequently smaller in cool climates and exposed sites. The flower heads open in autumn and winter and are orange-red. Plants do not grow well in alkaline soil.

Banksia integrifolia var. integrifolia - Coast Banksia

This hardy Banksia grows very well in coastal areas and can tolerate salt spray. Plants may grow to 25 m, but are often smaller. The dark green leaves have a silvery underside, which adds to the beauty of the foliage. The pale yellow flowers open from late summer to winter. Plants are frost tolerant.

Banksia marginata - Silver Banksia

Silver Banksia is a very variable species which may grow from 1 to 12 m, depending on the origin of the plant. Plants are hardy and will grow in a variety of soils and climates. Most forms are frost tolerant. The leaves have a silvery underside. The flower heads range from greenish yellow to bright yellow and open from late summer to winter. This is the only banksia which occurs naturally in the Canberra region.

Banksia serrata - Saw Banksia

The rugged bark, serrated leaves and large flowers of this banksia give it a distinctive appearance of great value in landscaping. Plants may grow from 2 to 12 m. It is adaptable to most soils, but requires good drainage, and is frost tolerant. The flower heads are greenish yellow and open from summer to winter. A low-growing cultivar B. serrata 'Austraflora Pygmy Possum' is available.

Banksia spinulosa var. collina

The dense habit of this banksia makes it a useful screen plant. It will grow in most soils, except those which are badly drained. The flowers are basically bright yellow but the styles range from yellow to deep red and change the overall colour of the flower head. They open in autumn and winter. Plants generally grow to about 2 m.