Is it a grass? Is it a tree? Actually it's closely related to a lily, but the Xanthorrhoea is in a class of its own. The particular species here is Xanthorrhoea semiplana,* and there are many hundreds on the block. This grass tree is widespread around the Lower South-east of the state wherever natural bush remains.
It took me a while to discover the true identity of what locals call 'yucca'. (Actual yuccas - of which there are 40+ species, are related to asparagus and native to southern USA and Mexico.) All 66 species of grass tree are endemic to (found only in Australia) and local Aboriginal people have traditionally used most parts of the plant. It's also an important plant for fauna - the 'cage' of drooping leaves provides protection for skinks, snakes, insects, small birds and mammals, while the flower spike is food for many parrots and honey-eaters, as are the insects it attracts. Last year some New Holland Honeyeaters successfully nested in a grass tree within the garden.
Several grass trees had to be removed before the house was delivered - and they don't go easily. A combination of hard and unyielding roots coupled with the densely compacted leaf bases made it hard yakka (sorry) for a person with a pick.
Roots around stem base
I've left quite a few in the garden area - they look good, especially after a tidy-up and provide a shady hideaway for all manner of small beings (including mozzies, unfortunately, who seem to live and breed quite happily in the moist centre of the plant). On the natural bush side of the fence the slow growing grass trees have the advantage of thriving in the poorest of soils so, with little competition they have amassed widely, and are particularly dense on the northern side, which is the most elevated.
The bees seem to be very excited, almost manic, when collecting pollen and nectar from grass tree flowers.
Grass trees provide food and habitat in the garden. This species doesn't always form a trunk and may be quite old if it does.*
Flowers emerge on the spike - they form a spiral pattern.
In come the insects, parrots and honeyeaters until...
You can see the black seeds centre left. The parrots are very fond of these.
I am about to have another attempt at growing a grass tree from seed to fulfil a friend's request. It's supposed to be easy, but the seeds didn't germinate the first time I tried.
If they do germinate I'll add some pics.
*SAM identified, from photographs, the grass trees here as X. semiplana. Because I hadn't seen one with a trunk I did further research and found a South Australian Government PDF - the conclusions and recommendations of a biological survey of the south east. It found eight major biological communities in the area - one being 'Low Woodland', characterised by the presence of Eucalyptus fasciculosa, Xanthorrhoea caespitosa. This made me wonder if that was the species here, however SAM confirmed it as semiplana from a photograph of a cross section of leaf. Since then I've discovered a semiplana sub-species that is trunkless - Xanthorrhoea semiplana ssp. semiplana*. I am now fairly positive that this is the species of grass tree here. Phew.
January - Grass Tree
February - Kangaroo Apple
March - Silver Banksia
April - Drooping Sheoak
May - Correa
June - Grevillea
July - Buddleja
August - Sundews
September - Native Hibiscus
October - Running Postman