Inland Spinifex a prickly and protective animal

When you grow Spinifex, or Porcupine Grass, in a botanic garden you want this hummock grass to hollow out in the middle to create a donut, or fairy-ring-like, structure. This one, on Howson Hill, in the Australian Garden at Cranbourne Gardens, is just a little bit curvy so far.

We label it Triodia irritans, which occurs naturally in Western Australia, Northern Territory and South Australia. Just one of 65 species of Triodia, all native to Australia, and nowhere else.

This name used to be what we called the sole species growing naturally in Victoria, but our populations - in the inland west of the State - are now called Triodia scariosa, which extends through to other mainland States (but not quite Northern Territory).

You and I can't tell these species apart so must rely on the labels in our botanic gardens. That said, grass flowers are fascinating and if you want to take a deep dive into their naming and classification, seek out Ian Clarke's Name Those Grasses: Identifying Grasses, Sedges and Rushes.

We can talk more generally about this particular grass. The hummock forming species of Triodia all get called Spinifex, a botanical name applied more correctly to a small group of coastal (sand dune) grasses.

That's why you often see Porcupine Grass provided as a common name instead.  You can see in this picture I took from near Fitzroy Crossing in northern Western Australia that when young, and separate, they do resemble something you might call a porcupine ... or hedgehog or echidna.

Still, I might stick to the botanical name Triodia from here on, just so I don't irritate or confuse any further.

Triodia spreads through stems, called stolons, creeping over the sand or clay. As the hummock spreads centrifugally, the roots and grassy bits die in the centre. Eventually you get a ring, or crescent, up to 3 metres or more in diameter.

Sometimes these hummocks join, resulting in wavy lines across the landscape. In gardens we can manipulate things a little by planting in a ring. Did we do that here in the Australian Garden? I can't say.

But I can show you this planting, where we have strung a few hummocks together, with no room to expand into anything like a wave or a donut.

In inland Australia these hummocks, no matter their final shape, are a good places for native animals to hide from wild cats and foxes. At Cranbourne they might do the same for our local bandicoots (the Southern Brown) although we do work hard at excluding feral animals (and grazing wallabies for that matter) from the Australian Garden.

It's a lovely site on an April morning, when these photographs were taken. And always these hummocks remind me of my childhood spent at least in part in Victoria's mallee.