General Description:
Banksia is a large genus of about 170 species in the Protea family, having been increased in size through the transfer of species in the former genus Dryandra to Banksia (see footnote box). The genus is almost exclusively Australian, being found in all States and Territories. A single species (B.dentata) is found in islands to Australia's north as well as in tropical Australia.
Banksia speciosa is an imposing shrub or small tree whose flowers are often commercially used in cut-flower arrangements. Mostly a many branched shrub to 4 metres, it may sometimes grow to double that size. The linear leaves may reach 45 cm long, and are divided into small, triangular lobes. They are green above and white underneath. Flowering may occur at any time but generally peaks in summer and autumn. The attractive, ovoid inflorescences are up to 12 cm long, 9 or 10 cm wide and cream to pale yellow in colour. The seeds are enclosed in large, woody follicles and are generally retained within the cone until burnt.
Banksia speciosa is fire-sensitive, and rapidly grows from seed after bushfire. It grows on deep sand in shrubland in nature. Though it is widely distributed, B.speciosa has succumbed in large areas of its natural range where it has been exposed to dieback fungus (Phytophthora). This could pose a risk to its survival in the future.
Due to its attractive flowers, Banksia speciosa is fairly commonly cultivated. It is a vigorous and quick growing shrub if given a well-drained sandy soil, dry summer climate and a sunny aspect. However it is extremely sensitive to rootrot which will kill it quickly. In humid climates, plants may grow quickly and appear to be doing well until they succumb to Phytophthora.
Propagation is generally from seed. There has been some success with grafting using its closest eastern relatives, Banksia serrata and B.aemula as rootstocks. A grafted specimen on B.serrata has lived and flowered for many years in the Australian National Botanic Gardens in Canberra.
The new classification has come in for some criticism but, as the Australian Plant Census has been adopted as the authority on plant names by ANPSA, the revised classification has been accepted on the ANPSA website. The previous Dryandra names will also be mentioned where appropriate. For further information refer to our Banksia page.
Banksia speciosa
Photo: Brian Walters
Australian Native Plants Society (Australia)