Many are valuable evergreen foliage plants, others subtle flowering types. Contrary to popular myth there are Carex for all soil types, from shallow water to pure sand!
Carex are not true grasses but are a genus in the Family Cyperaceae. The easiest (but not foolproof) way to tell them from true grasses is that most members of the Cyperaceae have flower stems with a more-or-less triangular cross-section. Most true grasses have flower stems with a round, hollow, cross section.
Many Carex are used as evergreen groundcover or edging plants and many of the low growing, variegated forms originate in Japan where they have been used alongside Ophiopogon and Liriope in traditional Japanese gardens. There are also numerous fresh to deep green leafed forms, including British native species, that can fulfil a similar roll.
At the other end of the spectrum there are the mostly brown leafed species and forms from New Zealand. These will mostly need full sun but can take quite moist through to fairly dry soils. The limiting factor with most of these "dead sedges" with their evergreen (brown) leaves is that they are vulnerable to extreme cold in winter with many only hardy to -10oC.
An excellent golden variegated evergreen sedge from Japan that makes neat clumps of arching leaves. Easy and hardy for ordinary soil in sun or light shade. 15cm.
A New Zealand native sedge forming clumps of relatively wide green leaves and upright stems with arching light green flowers in summer. From wet places but seems happy in most soils! 50cm here.
A colourful sedge from New Zealand making neat clumps to 30cm. Olive green strongly tinted with bright orange especially overwinter. Evergreen. Best in good (even damp) soil in sun.
Bright green mat forming sedge. Produces masses of equally bright green, dainty, flowers on delicate stems to 25cm in spring. A good edger for shady borders. Average soil.
A larger clump forming sedge from New Zealand with grey backed rich green leaves curling over to make an attractive evergeen. Heavy looking brown flowers in summer to 80cm. Good soil in sun.
Unmistakeable clumps of burnished mahogany red evergreen foliage on this stunning New Zealand sedge. Best in damp soil in some shade but tolerates less of both! Neat gorwer to 25cm.