Carex oshimensis ‘Evergold’

What is a sedge?

BBC Gardeners' World Magazine

Published: Wednesday, 3 November 2021 at 1:35 pm

We explain what a sedge is, and compare sedges to grasses and rushes.

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Sedges are grass-like plants, grouped alongside ornamental grasses and rushes, although all of these plant types are botanically different. Distinguishing one from another is useful for the purpose of siting and planning garden planting, as each type has different growing requirements. True grasses mostly originate from open sunny environments, while sedges tolerate shade and extremes of moist or dry soil. Rushes do best in moist soil, boggy ground, or shallow water.

Find out more about sedges, as well as grasses and rushes, below.

Sedges

Carex comans

Sedges are classified in the family Cyperaceae and are found worldwide. This is a vast and diverse family of plants, comprising several thousand species and varieties. Sedges can be identified by their stem shape, which is triangular when cut. The small flowers are brown or black and borne on slender stems.

Sedges for garden planting are predominantly from the genus Carex and are useful in the garden as many are evergreen, with foliage colours that range from bronze to gold, variegated and glaucous. The majority are clump-formers and are not invasive, although some sedges do spread by underground, running stems. Because of their diverse origins from around the world, growing requirements vary from moist to dry soils. Cyperus species are also sedges, and include moisture-loving Cyperus involucratus, a handsome pond plant.

Sedges include:

Carex flagellifera
Carex comans 'Bronze Form'
Carex oshimensis 'Evergold'
Carex buchananii 'Red Rooster'
Carex testacea
Cyperus papyrus

True grasses

Hakonechloa macra

Grasses belong to the family Poaceae and have hollow stems, which are known as culms, divided by nodes (leaf joints) from which the leaves grow. Most are perennial, dying back to the ground in autumn and regrowing in spring, with some annual species that complete their life cycle in one growing season. Their flowers are borne in spikelets and are often very showy. In the main, ornamental grasses do best in sun or light shade and, because of their origins from different countries, they have varying soil requirements.

True grasses include:

Hakonechloa macra
Miscanthus sinensis
Pennisetum orientale
Anemanthele lessoniana
Stipa tenuissima

Rushes

Pond in a pot with Equisetum scirpoides, Juncus ensifolius, and Cyperus involucratus

Pond in a pot with Equisetum scirpoides,
Juncus ensifolius, and
Cyperus involucratus

Rushes and woodrushes belong to the family Juncaceae. These are moisture-lovers, requiring pond or stream-side planting, bog gardens, or moist soil. In gardens they're represented by the genera Juncus and Luzula.

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