Sedge Carex appressa

Tall sedge forms a dense arching evergreen tussock of narrow leaves with a rough margin sharp enough to cut skin, topped in spring by brown to almost black flower spikes on stems that are triangular in cross section. Below ground it builds a heavy fibrous root mass, which is the real reason it gets specified. It turns up on more raingarden schedules than almost any other Australian tussock, holding batters, dam edges, swale bases and the corner of a block that never quite dries out while a site stabilises.

Site it wet and leave it wet

It grows across most of southern and eastern Australia, including Tasmania, and it is not fussy about climate, frost or soil type provided moisture is there. Full sun and part shade both work, and it performs in clay, in filter media and in heavy waterlogged ground that kills ordinary garden plants. Plant it at four to six per square metre for continuous cover on a batter, closer where the soil is actively moving and cover is needed before the next storm. The failure mode is dry ground. It survives there once established, which is why it keeps being planted in dry beds and then written off, but it never looks right: leaves brown off from the tips down, the tussock opens up through the middle and the whole planting goes grey and ragged by February. Either water it or site it where water collects. Wear long sleeves and gloves when handling it, and keep it back from paths where bare legs brush past, because the leaf margins genuinely cut.

Sedge or rush for a basin

The plant it competes with directly is Juncus usitatus. Juncus has round leafless stems, finer texture and a habit of seeding itself across a damp site, which suits revegetation and irritates anyone maintaining a formal basin. Carex stays where it is put, covers more ground per plant and binds soil harder, so it is the better pick for a bank that has to hold and for anything a client will inspect. For the drier upper part of the same batter, above the waterline, Lomandra hystrix takes over, since it handles damp ground without needing it and keeps its form through a dry summer.

The hard cut back in late winter

Every two to four years cut the entire clump back hard in late winter, close to the base, to clear accumulated dead leaf and thatch and force clean new growth for spring. Doing it before new leaf emerges means no cut ends left browning at the top of the tussock for the rest of the season. Gloves and long sleeves again, and a brushcutter rather than shears on anything larger than a garden bed. Feeding is optional on most sites, but a slow release fertiliser in the first spring after planting speeds the cover along, and a top up after a hard cut back helps the clump rebuild. See more native options in natives.

Choosing a size

This plant is available in 4 sizes, from 75mm up to 175mm Squat, priced from $16.95 to $32.95 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.