The Grasstree

Just like a parent, a gardener shouldn’t have favourites. But you do, don’t you? Can’t help it. The grasstree Xanthorrea is one of three favourites in my garden that I can’t choose between, each of them achieving ‘Best in Garden’ status for completely different reasons. So what does the grasstree do to deserve this exalted status? Well firstly, with apologies to gums and wattles, I don’t think there is a more visually distinctive Australian plant. That mop of arching grey-green leaves, the collar of scruffy dead brown leaves, the squat, blackened and crooked trunk, and the spear of the flower spike, thrusting heavenwards, you see a grasstree in the landscape, and you know you are definitely not in Kansas anymore. You could only be in Oz. Those hoary, twisted, ancient trunks could not be from anywhere else.

Grasstrees are superbly adapted to the hungry soils and firestorms of this dry continent. With their ability to regrow after intense bushfires they can grow to be hundreds of years old and very big. In some heathland communities on particularly hungry soils, they are easily the tallest species of plant, standing head and shoulders above the rest. This outstanding specimen in the Royal Botanic Gardens of Victoria stands over six meters tall and has multiple crowns.

They will only flower and set seed after a good burn enriches the impoverished Australian soil with a bit of extra nutrient to assist new seedlings through that first difficult year out of the seed. They won’t flower unless they smell smoke in the air, which initiates the flowering process. Indeed, that’s how I get mine to flower so frequently… I set fire to that scruffy collar.

I am also fond of the Xanthorrhea because it’s such a slow grower. My garden is so small that most plants need to be regularly trimmed to size or completely removed when they get too big in order to maintain the scale and proportions of the garden, but not the Xanthorrhea.  The trunk on mine has managed to grow about 30 cm in 20 years. (This is an estimate because it is a bit hard to say exactly where trunk stops and leaves start.)

And mine was titchy to start with, a trunk of 40 cm with punky tuft of spiky leaves poking out the top. It didn’t look like it would ever amount to much. However I couldn’t afford the prices they were charging for the big ones being planted out at hip cafes and funky apartment developments in the mid-90s. Most of those died, or were replaced by cacti when the fad died. But that fashion and its aftermath gave Xanthorrheas a reputation for being tricky, which is unfair. They are dead easy to grow provided they get decent drainage. Most of the failures were planted into heavy clay soils.

I am unable to identify what species of Xanthorrea I have in the garden. It was purchased labelled as Xanthorrhea australis. However, this one seems to display some features of other species. I have heard that, like eucalypts, Xanthorrheas hybridise easily and I suspect that’s what I have.

I purchased this one on impulse, because I love the form, and to see if I could make a go of it. ‘Shouldn’t be too difficult,’ I rationalised. (The last words so many plants hear as they become impulse purchases.) But it wasn’t that long ago that Xanthorrheas were dotted through the coastal heath that clothed the sandstone plateau hereabouts. This time those famous last words weren’t a death sentence. It loved the sandy soil, didn’t mind the salty sea breezes, and survived the Millennial Drought without a drop of extra water, all the time growing at about 5cm a year. All I had to do was make sure when I augmented the rest of the garden soil with truckloads of organic matter (for the more sensitive little flowers), I didn’t add a scerrick to the ground where the grasstree would be planted.

Placing the grasstree at the end of the small mound behind the pond was definitely more arse than class. At the time I laid out the garden, our house was being renovated, so we didn’t know how we’d end up using the space. It turns out we spend a lot of time on the back deck or in the back room, and from there the grass tree is smack bang in the middle of the garden. As the focal point in the asymmetric design, the grasstree makes a strong visual statement, particularly as it ages. With thick black trunk and arching foliage that plays with sunlight like a fountain when sea-breezes blow, it makes for an eye-catching centrepiece.

Originally, I wanted a strong vertical element to contrast with the rounded and cascading forms that predominate visually. I planted a dwarf thuja for this effect,

but the conifer bolted like a frightened horse in this temperate Sydney climate

I had to pull it out after 10 years. All out of proportion!

But now the Xanthorrea gives us vertical in spades. In fact looking at the powerful upthrust of its flowering, you’d swear I’d been feeding it Viagra.

When the flowering spikes emerge they can grow 20cm in a day. It is an exciting time just to come home and see how much it grew today.

And right now it’s especially exciting. A couple of years ago I noticed that the plant appeared to be developing two crowns. But the arrangement of leaves is so crowded and jumbled up at their bases that it was impossible to tell for sure. A couple of weeks ago I noticed a flower spike emerging through this bowl of spaghetti. And then last week I noticed a second spike emerging. Two spikes! Yes. Now I can be sure that the grasstree has definitely branched. 


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