Spear Grass Austrostipa densiflora

Among the Australian spear grasses, Austrostipa densiflora is one of the more compact species, holding a tight tussock of fine, rolled leaves that stays upright instead of flopping open at the base. Flowering stems rise well clear of the foliage in a narrow, densely packed head, and each seed carries the long twisting awn typical of the genus, which is where the common name comes from. It is planted for mass planting, border texture and erosion control, most often in revegetation, dry meadow schemes and road verges.

Full sun, poor soil, and why not to spoil it

Full sun and free draining ground are the requirements, and once established it runs on low water, which makes it useful on banks and verges that never see irrigation. Growth is moderate, so a mass planting furnishes within a couple of seasons provided weeds are kept down early. Plant in drifts, closely enough that the tussocks touch as they mature, rather than dotting single plants through a bed. The failure mode is kindness. In rich, watered ground it grows soft, the tussock flops open from the centre and the crown rots, and no amount of trimming brings the tight upright form back. Poor soil, no fertiliser and no summer irrigation give a better plant. Two practical notes before you buy. Those awns are sharp and work their way into socks, laces and dog coats, so keep this species back from paths and play areas. And because Austrostipa closely resembles the declared weeds Nassella trichotoma and Nassella neesiana, hold on to your labels and paperwork, particularly on rural land where an inspector may need convincing.

Native tussock or turf

Nothing else here does what a tussock grass does, but two plants get cross-shopped with it. Korean velvet grass is turf: a surface you walk on, mown or left to mound, with a long establishment period. Austrostipa is not a surface at all. It is a plant you look at, in drifts, and it should never go where people walk. Morning iris is the alternative if you want a tufted native with a flower and no awns, and it is the better choice next to a path or a driveway edge where seed heads would otherwise catch on clothing. Put the spear grass on the bank, the zoysia on the flat and the morning iris along the edge, and each one is doing the job it is actually built for.

The late summer cut back

Cut clumps back hard in late summer once the seed has shed, taking the whole tussock down to a short stubble with shears or a brushcutter. It reshoots cleanly from the crown and comes back tighter than it went in, and cutting at that point also removes most of the seed before it travels. Do not cut it back repeatedly through the growing season. Feeding is not part of the routine; this is a species adapted to low fertility ground, and fertiliser produces exactly the soft, open growth that the late summer cut is meant to prevent. Water through the first summer only, while the crown takes hold.

Choosing a size

This plant is supplied in one size, 140mm, at $19.95 per plant. The size shown is the pot it arrives in, which is the rootball, not the height of the plant. Not sure which to choose? Read our guide to when to plant in Australia.