There are around 53 species in the genus Conospermum, most of which are endemic to south-western Western Australia. There are nine species in the eastern states. Conospermum belongs to the protea family (Proteaceae) and the plants are commonly known as smoke bush. In their natural state, they are found on well-drained, sandy soils. They are sometimes found on the edges of swamps and are generally among plants of a similar height, ensuring they receive plenty of sunlight. The ‘smoke bush’ term arises from the masses of white to greyish flowers that appear in thick masses giving the impression of smoke. The smooth-margined leaves are simple, spirally arranged and may be very elongated.
Some of the species are well-known and relatively common.
Conospermum burgessiorum grows to 3 metres and comes from the mountainous areas of south-east Queensland and north-east New South Wales. The young branches are hairy, becoming hairless as they mature. The bell-shaped, cream to white flowers appear in clusters at the ends of the branches. Flowers are produced from spring to early summer.
Another conospermum from the eastern side of Australia is Conospermum longifolium (long-leaf coneseeds). This erect, slender shrub occurs in heath, woodland and sandstone country. The long, spathulate leaves are wider at the tip and taper to their base. The white flowers are hairy on the upper surface. They are produced on long stalks in winter through to spring.
Conospermum teretifolium is found in the south coast heaths of Western Australia. The bare branches have rush-like leaves which may reach 30cm in length. White to cream tubular flowers are produced from spring to summer. It requires really well-drained soil.
Most widespread of the WA species is Comospermum stoechadis. It is popular as a cut flower. It is a spreading shrub and is densely branched. The leaves are needle-like and curved. Although covered in hairs while immature, the hairs disappear as the leaf ages. The white to grey flowers are very woolly and are produced in spring.
Conospermum triplinervium is native to the Perth region and nearby wheatbelt area. It is almost tree-like reaching a height of 4.5 metres and with erect branches. White to grey flowers are borne on spikes. The flowers are tubular and densely woolly.
Smoke-bush will not thrive in hot and humid climates. They are ideal for semi-arid areas with light soils and excellent drainage. While they will survive light frosts, heavy frosts are a different matter. Bushy growth can be promoted by pruning lightly after flowering. Propagation is best undertaken by taking cuttings from vigorous shoots. The flowers are long-lasting and popular for floral arrangements and decoration.
