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A Very Beaut Banksia!

Norbert Schaeper

In 1999 I planted a Banksia robur in an area that is often damp, with morning sun and afternoon shade, below a retaining wall at the back of my house. It has grown into a handsome, spreading, 2 m tall by 2 m wide open shrub that is one of my favourite plants in the garden.

The leaves are large (30 cm x 8 cm) and leathery, bright green with a contrasting yellow vein down the centre. The underside of the leaves is white, providing further colour contrast. New growth is velvet red through to pink, yellow, green and brown. There is a form of Banksia robur from Bulli that has very dark green leaves and a red centre vein and I've been told of a specimen in Canberra with leaves so dark that they appear almost purple. The stems have smooth grey bark and grow from a lignotuber or woody swellings at and below ground level. A lignotuber can produce new growth after a fire has burned the rest of the plant. Plants with a lignotuber can be heavily pruned and will respond with new growth just as if they had been through a bush fire. My plant has numerous rusty brown buds on the lignotuber, lying dormant, waiting for a bush fire (or pruning saw) to stimulate new stems to shoot.

Banksia robur   
Banksia robur
Photo: Keith Townsend
  

What are normally thought, of as banksia flowers are actually dense spikes of hundreds or even thousands of individual flowers. There is a central woody axis and the flowers are arranged on the axis in double spiral patterns. The first sign.of a new flower spike is the yellow tip of an axis emerging from a ring of small rusty brown, velvet leaflets. The axis grows upright and to roughly 100 mm long and 15 mm diameter. Small green brown and yellow flower buds dot the axis. Over weeks the flower buds begin to elongate, growing out from the axis and the spike begins to look like a bright green bottle scrubber. As the elongated flower buds open they change from green to golden, then become darker, and eventually brown. Then over months they fade to grey and after any pollination has taken place the woody velvet brown seed pods begin to form. Not all flowers develop these hard, nut-like fruits - there would not be room for hundreds of them to form on a single flower spike - and some spikes produce no pods at all.

My plant flowers at various times throughout the year and there are usually a number of flowers in various stages of development and appearance. Birds seem to be most interested in the flower spikes when they are golden. Most. frequently I have seen Noisy Minors, but at other times there will be the occasional Wattlebird having a feed. There are over 20 old grey flower spikes on it, but only one has produced any seed pods.

I have a second Banksia robur planted in a drier area. It has not fared so well. In wetter periods it thrives, but during very dry spells it dies back to the lignotuber, remaining dormant until the next rain when it shoots again. My experience is that Banksia robur is a hardy plant and, if provided with sufficient moisture, it thrives into an attractive and open shrub that is small enough for most gardens but large enough make an interesting feature plant.



From the newsletter of the Sutherland Group of the Australian Plants Society, November 2003.



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