Carex Sedges

How to choose a carex

Start with the job. For wet ground, a pond edge, a rain garden or a swale, the native tall sedge (Carex appressa) forms a dense tussock to about 90cm that filters runoff and holds a bank, and it is the one revegetation projects use across south-eastern Australia. For a border or a pot in shade, the ornamental forms stay between 30cm and 40cm. Evergold has cream and gold striped leaves that light up a dark corner. Blue Wave and Blue Cascade are blue-grey, the second with longer, more arching leaves that spill over a pot rim. Frosted Curls is a fine, pale bronze-green tussock with curled leaf tips, and Belinda's Find and Moon Falls are compact, bright-edged forms for small spaces.

Where carex works

Part shade to full shade for the ornamental forms, with morning sun welcome; full sun is fine for Carex appressa if the soil stays moist. Carex suits the ground under established trees where little else grows, the shaded strip beside a house, pots and troughs on a south-facing balcony, mass planting along a path, and the margins of ponds and drains. It grows in every Australian capital. In Brisbane and the subtropics give the coloured forms the shadiest, most sheltered position; in Melbourne, Canberra and Hobart they take frost without damage. Pair them with the other grasses and strappy-leaved plants or the ferns and hostas of a shade garden.

Planting and spacing

Plant any time the ground is not frozen or baked, in soil improved with compost, and keep new plants watered through their first summer. For a mass planting of the small ornamental forms, space 30cm to 40cm apart; for tall sedge along a pond or a swale, 50cm to 60cm. In pots use a premium mix and a saucer in summer, since carex dislikes drying out. Our guide to grasses for planting under trees covers the drip-line situation in detail.

Care basics

Water in dry spells; unlike most ornamental grasses, carex wants steady moisture and will brown off if left dry in summer. Feed once in spring with a slow-release fertiliser. Comb out dead leaves with gloved fingers in late winter rather than cutting the clump back hard, which many carex resent; tall sedge can be cut to 15cm every few years to renew it. Divide crowded clumps in autumn or spring. Pests and diseases are rare. The coloured forms occasionally throw a plain green shoot: remove it at the base.

Common questions

Does carex grow in full shade?

Yes, better than almost any other grass-like plant. Growth is slower and the gold and blue forms colour a little less strongly in deep shade.

Can I cut carex back like an ornamental grass?

Better not. Comb out the dead leaves instead. Only the native tall sedge takes a hard cut, and only every few years.

Is carex native to Australia?

Carex appressa is, and it grows naturally in wetlands and along creeks from Queensland to Tasmania. The ornamental coloured forms are garden selections from New Zealand and Japanese species.

Will carex spread?

The forms here are clumping, not running. Clumps widen slowly and can be divided; none of them spreads by runners or seeds about as a weed.