Xanthorrhoea species (Grass Trees)
Xanthorrhoea priessii is a Western Australian species. This species was one of the plants used by the winning garden at the Chelsea Flower Show. Xanthorrhoea quadrangulata and Xanthorrhoea semiplana are the South Australian species of Grass Tree.
At an Arboretum near here, Xanthorrhoea preissii and Xanthorrhoea semiplana have both been planted on deep sand. After four years of growth in the ground, the cluster of leaves is about 60cm tall and beginning to ‘vase’ out in a very graceful way. The width of the clump is larger than the reach of two hands joined finger tip to finger tip as if holding a large bunch of flowers.
It is certainly worth while growing these for the leaf display if this is what the growth is like after 4 years. Xanthorrhoea semiplana generally does not make a trunk although sometimes one up to a metre will appear, whereas the other does to about 3 metres tall. However to see a ‘decent’ trunk on Xanthorrhoea semiplana in one’s lifetime is probably only to be dreamed about!
Xanthorrhoea need a sunny well drained position. They look wonderful growing in a rockery and will also look great in a large pot as an impressive feature plant. Specimens have flowered after 7 years in Brisbane and 10 years at the Australian National Botanic Gardens.
It has been discovered that the Yellow Tailed Black Cockatoos love the seed pods that form along the flower stem which can be as much as 4-5 metres tall. They have been observed eating them soon after sunrise between Tintinara and Keith on the side of the road.