Edited 10 September 2011
Xanthorrhoea glauca subsp. glauca (Xanthorrhoea australis)
This lovely tree is one of the glories of Toowoomba, particularly in September when it attracts birds and a throbbing mob of insects with this incredible display of flowers.
You can see it on the corner of West and Herries Streets, opposite Laurel Bank Park.
I was delighted to have been able to hear the true story of the planting of this tree in 2011, from the man who planted it, Mr Ray Lamb.
The house, which is now a veterinary surgery,
was built (in 1924) by Herbert William (Bert) Lamb. Bert was a prominent Toowoomba businessman, and he and his wife Muriel had a strong interest in natural history. His son Ray was born there in 1926.
Ray found the grasstree during a visit home to his parents' house, very soon after the second world war. It originally grew near the beginning of the walking track to Tabletop. In those days the track would have started near the top of the Range, at the end of South Street. The grasstree was then only quite small. (Mr Lamb estimates that it was about 18 inches high.)
He dug it up and transplanted it into an old asparagus bed near the back gate of the house. The soil was extremely well prepared. His father had dug a hole about 3 feet square and 3 feet deep, and filled it with soil enriched with a large quantity of manure.
The plant obviously thrived in its new home, giving the lie to all those tales of grasstrees being extremely slow-growing. These tales are apparently based on measurements of the growth of an Australian grasstree taken back to Britain, and planted in the Edinburgh Botanic Garden - hardly the optimum environment for this largely sub-tropical species!
The plants were once common on the blacksoil of the Darling Downs. Ludwig Leichhardt commented on them, in the Journal he wrote in 1844. He found them remarkable as they grew on rich, heavy, clay soil, whereas most of Australia’s grasstrees (including other X. glauca subspecies) will only grow very well-drained hillsides where the soil is rather infertile. The trees he saw were growing out on the plains, often near creeks. There are still a very few of these original trees left, but as the flat land where they grew is also some of our richest agricultural land, most of them have gone to clearing.
The tree does also grow on our red and black basalt soil slopes, but it is worth knowing that this species is a hardy, drought and frost tolerant species which will happily grow on in the heavy black soil of our plains, tolerating occasional severe flooding.
The story of the planting in a heavily manured pit reinforces the fact that this grasstree subspecies responds well to rich soil and will tolerate poor drainage. I suspect the treatment would be just the way to kill most kinds of Xanthorrhoea!
Grasstrees are more closely related to lilies than to “proper” trees, and share the lily tendency to have the leaves and flowers all coming from a central point. They can take up to ten years to begin to develop a trunk, sitting on the ground like a giant pom-pom meanwhile. Even at this stage, they are ornamental in gardens, their elegant leaves stirring gently with every breeze. This movement is a significant part of their beauty.
As the trees gets older they a dry “grass skirt”, and people have varying opinions as to whether this looks good or not. Some of us think that the blackened stem of burned trees is a more natural and authentic look. In their original environment they would always have been subject to burning every few years.
People who feel they can safely do so might like to burn their trees every so often. There is a rumour that this practice hastens the growth of the trunk, but local experiments haven’t supported the theory. It may, however, promote flowering once the tree is old enough.
It is a pity that nurseries have a tendency to sell grasstrees without stating what species they are.
Our local species can be bought, but you might have to do a bit of work to source the right thing.