Grass Tree Xanthorrhoea glauca

A grass tree with a trunk is decades of growth you cannot hurry. The trunk is built from the bases of old leaves cemented together with resin, and it lengthens by something in the order of a centimetre or two a year, so a plant standing at waist height has been growing for a very long time. Xanthorrhoea glauca is the eastern species named for its blue grey colouring: a dense head of fine, stiff leaves fountains out from the crown, and the old ones fold down into a pale skirt over the trunk if they are left alone. Mature plants of this species often fork, carrying two or more heads on the one trunk, and that branched outline is what it is known for.

It comes from the slopes and ranges of eastern Australia, from south east Queensland through New South Wales into north east Victoria, so frost, cold winters and long dry spells are part of its normal life. What it does not tolerate is a wet, airless root zone, and nearly every grass tree lost in a garden is lost to that.

Plant it high, then leave it dry

The roots are fine, shallow and easily rotted by soil organisms such as Phytophthora, and a newly planted grass tree can hold a green crown for months on stored reserves, so trouble often shows long after the cause. Plant it at exactly the depth it sat in the pot, never deeper, in ground that drains freely: sand, gravel, a rocky bank or a raised mound. On clay, build the planting area up well above the surrounding soil with a gritty mix rather than digging down into it. Water it in thoroughly, then let the soil dry out between drinks, keep irrigation lines away from it, and aim water at the soil rather than into the crown, where it can rot the growing point. Fresh green leaves pushing from the centre are the sign it has taken; a crown that yellows and lets leaves pull out with a light tug has rotted. Skip fertiliser in the first year, and after that a light sprinkle of low phosphorus native fertiliser in spring is as much as it needs. Planting an advanced tree covers hole preparation for larger plants, though for this one the drainage rule outweighs everything else. Grass trees are protected plants in New South Wales, Queensland and Victoria, so a large trunked specimen should come with its state tag or salvage paperwork; keep it with the plant, because you may need it if the tree is ever moved or sold.

Where a grass tree earns its space

Give it full sun or the light, open shade of eucalypt woodland. Set against rock, gravel, a rendered wall or a low carpet of groundcover such as Creeping Boobialla, a single specimen reads as living sculpture, and a group of three at different heights makes a slope or a native garden look settled from the first day. It also suits a large, heavy pot filled with a coarse, very free draining mix, which is a good answer for a courtyard on clay. Keep it back from narrow paths and doorways: the leaf tips are stiff and sharp enough to scratch legs, and on a tall trunk they sit close to eye height.

Among the Australian Native Plants, few need less once settled, which is why it sits in the Low Maintenance Plants range, but that label applies after establishment, not before. The skirt of dead leaves can be trimmed off for a clean trunk or left on for a natural look and as shelter for lizards. Never burn it in a garden. Flowering is irregular: in the bush it is often triggered by fire, so a garden plant may go several years between spears. When one does come, the tall spike of small cream flowers is loaded with nectar and draws bees, other insects and honeyeaters for weeks.

Choosing a size

This plant is available in 5 sizes, from 300mm up to 800mm, priced from $309.00 to $4719.00 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. Every size here is established stock rather than a starter plant, so this line is intended for immediate effect rather than for growing on. Not sure which to choose? Read our guide to Australian native trees.