Grass Trees
A survivor from the age of dinosaurs, the unique Australian grasstree (Xanthorrhoea sp.) has tenaciously survived 200 million years of climate change (both ice ages and extreme aridity) and is amongst the oldest flowering plants in the world. These plants are superbly adapted to poor conditions, grow very slowly and are long-lived. The name is a misnomer
– it is neither a grass or a tree, but distantly related to the lilies. Like the grasses, however, its leaves are long and narrow.
Photograph by Neil Murphy.
There are many species of this endemic plant, fifteen of which occur in Queensland. They range in size from a tuft of leaves close to the ground to towering forms that may have a trunk 6 metres high (as seen in the Springbrook Ranges). Given well-drained soil and full sun, these plants will grow just about anywhere, as witnessed by their distribution from coastal regions to mountain tops. Their root system is fibrous and has a strong association with a fungus (mycorrhizae) that helps them take up nutrients. In addition, the roots can contract so that the apex of the plant can be 10 cm below the soil level. Even if it is a species that forms a trunk, it may exist as a rosette of leaves at ground level for up to 30 years before the trunk becomes visible. The trunk is also unique in that it is formed by leaf bases cemented together with an aromatic resinous gum which hardens into a protective jacket resistant to insect and fire damage. The plant usually produces one complete whorl of leaves each year so that its age can be determined by counting the rings of leaf bases that are a few centimetres apart.
This iconic species is worthy of a place in any garden with its lovely skirt of leaves from which tall flower spikes, holding thousands of small cream flowers, emerge. It provides an important wildlife habitat as both a source of food and shelter for a diverse range of animals. The nectar is a food source for lorikeets, honeyeaters, ants and butterflies. The latter attract insect-eating birds. Cockatoos thrive on the seeds. Some species of native bees, e.g. the green carpenter bee, in addition to harvesting pollen and nectar, make nests within the pithy stems of old, dry flower stalk. The dense leaf skirts are used as nesting sites for fairywrens, scrub wrens, lizards and small mammals such as the yellow-footed antechinus and common dunnart.
The nursery has both tube-stock and advanced grasstrees for sale.
Photograph by Neil Murphy.
