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 3-weeks to 1-month. When large enough to handle prick out 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 flat broad linear leaves are up to 12 mm (½ in) wide with an obtuse apex, serrated margins and a short petiole. The new foliage is covered in tomentose becoming glabrous with age.
Flower: The small tubulate flowers have yellow perianth segments are up to 45 mm (1µ in) long and are glabrous. The protruding straight pistil is up to 40 mm (1? in) long.
The flowers are arranged densely in a terminal broad cylindrical spike on lateral branchlets and are up to 90mm (3½ in) long andwide. They appear during summer and old styles persist on the plant while perianth segments fall away.
Fruit: There is up to 70 elliptical follicles that are to 12 mm (½ in)wide and are covered in fine tomentose. They are arranged densely in a woody cluster that opens after fire to release 2-narrow obovate seeds to 23 mm (µ in) long that have a smooth wide notched wing to 12 mm (½in) 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.