Propagation
Fresh seed should be sown in a well-drained media and the kept moist but not wet. Maintain a temperature of 18º to 21º C. (64º to 75º F) in an unheated glasshouse or open frame.
Germination occurs within 17-days to 54-days then prick out when large enough to handle and pot up. Careful not to over water seedlings, as they are prone to damping off and larger plants are difficult to transplant.
When removing seed from Banksia fruits it may be necessary to place the fruit in an oven for 60 minutes at a temperature of 120° C. to simulating the effect of a bushfire to opening the valves.
Botanic information
Leaf: The narrow linear leaves have an acute apex that is mucronate and revolute margins. The upper surface is glabrous and the underside is white woolly. They are scattered and crowded along the branchlets towards the top.
Flower: The small tubulate flowers have purplish-brown perianth segments that are up to 33 mm (1¥ in) long and are pubescent on the outside and the protruding straight pistil is up to 36 mm (1? in) long and curved at the apex.
The flowers are arranged densely in a terminal pendant cylindrical spike that is up to 70mm (2?in) long by 75mm (3 in) wide. They appear during summer and old flowers persist on the plant. The flowers are pollinated by a small marsupial (Tarsipes rostratus) that feeds on the pendant flower heads.
Fruit: The numerous oblong-elliptical follicles are up to 38 mm (1½ in)wide, often flanged. They are arranged densely in a woody cluster opening after fire to release smooth cuneate-obovate seeds that are up to 27 mm (1? in) long and have a wing to 25 mm (1 in) wide.
General pruning information
When pruning reduce only the new growth as cutting old wood is likely to cause dieback. Limbs may be removed back to the collar.
Cultivation
Generally, Banksia species prefer a well drained, sandy soil that is tending acidic but many species from Western Australia grow on acidic top soils with alkaline subsoil.
When the growing Western Australian species outside their native habitat technique of building a garden bed, of acidic soil above a layer of agricultural lime commonly produces better results particularly in raised garden beds or on slopes. During establishment, keep the soil moist but not wet and do not use fertiliser that contains phosphorus.