Nov 18, 2014
The gnarled little trees called wallum banksia thrive in the sandy heathlands along Australia's east coast, from Queensland down into northern New South Wales around Sydney. Tall spikes of yellow-green flowers linger for months on the branches, drying out and turning brown and then gray; the knobby fruits–seed follicles–may hang on the plant indefinitely, at least until a brush fire sweeps across the countryside, which is something that happens there about every seven to twelve years.
Wallum banksia are not harmed by fire, nor by salt spray or nutrient-starved sandy soil or extended drought. The species has evolved to thrive in extremely harsh conditions, in a habitat which, like the species itself, is known as wallum.
Fire may burn up the leaves and branches, but it also pops open the seed follicles, allowing new little wallum banksia to sprout up all around the old ones. Also, the roots often push up new growth after a fire, helping the species reclaim the territory from other opportunistic seeds that might be trying to spread thereabouts.
The specimen pictured here is not in Australia at all, but in the Australian garden area of Wellington Botanic Gardens in New Zealand. The climate in almost all of New Zealand is cooler and far moister than in most parts of Australia, and wallum banksia does not grow naturally in New Zealand. In fact, it is said that the healthiest, largest, fastest-growing specimens are in dry, sunny, fire-prone locations with poor soil comprised mostly of sand.