Creek Mat Rush Lomandra hystrix

Creek mat rush is the tall, full, soft looking one. Its leaf is glossier and brighter green than the other mat rushes here and it arches over at the tip instead of standing stiff, so a mature clump reads as a fountain rather than a fan. It comes from subtropical creek banks, which is where its usefulness lies: it sits in ground that stays damp far longer than its relatives will, and it is planted on batters above waterlines, in swale bases and through shaded courtyards.

Damp ground, shade, and the cold limit

Warm coastal and subtropical gardens are its home range, and it does well through Brisbane, the Sunshine and Gold Coasts, Sydney and coastal northern New South Wales. It handles full sun to part shade and keeps better form in shade than most strappy plants, which is why it ends up in dark side courtyards and under established trees where other tussocks thin out. Soil can be clay, loam or filter media, and periodic inundation is no problem. For mass planting use 600 to 700 millimetre centres, roughly two to three plants to the square metre, allowing for a clump that gets genuinely large. The failure mode is cold. This is the least frost hardy mat rush in the range, and in Canberra, Ballarat, Armidale or an inland frost hollow it comes through late winter with burnt tips and brown outer leaves that take until midsummer to grow out. In those districts plant its southern relative instead, since burnt hystrix leaf sits there looking bad for half a year while longifolia shrugs the same frost off. One siting note: the flower spikes are prickly, which is what hystrix means, so set it back from paths where children brush past.

Hystrix or longifolia

These two get swapped on site and they are not interchangeable. Lomandra longifolia is stiffer, duller and darker in the leaf, more rigidly upright and far tougher through frost and drought, and it is the one for exposed road batters in cold or dry country. Hystrix is taller, softer, brighter and better in damp shade, and it reads as a garden plant rather than a roadside one, which matters in a courtyard where people see it up close. Where the ground is actually waterlogged rather than merely damp, step down to Carex appressa, which handles standing water that will eventually rot a hystrix crown.

Cleaning out old leaf

Clean the clump by cutting it back hard, low and all at once in late winter, every three or four years, rather than shearing the tops flat. Flat shearing leaves cut brown ends sitting at eye level for months, which is the usual reason a planting looks worse after maintenance than before it. Between hard cuts, pull dead leaf out by hand and remove spent flower spikes. Feed with a slow release native fertiliser low in phosphorus in early spring, particularly in the season following a hard cut back, and water through the first summer while the clump establishes. More in natives.

Choosing a size

This plant is available in 5 sizes, from 125mm up to 300mm, priced from $16.95 to $88.95 per plant. The size shown is the pot the plant arrives in, which is the rootball, not the height of the plant. These are younger plants, priced for planting in quantity, and they establish quickly once in the ground. Not sure which to choose? Read our guide to low water gardens.