In Praise of Carex
THEY LOOK LIKE GRASS, YOU SAY? Indeed sedges, rushes, and grasses superficially look alike. Look more closely, however, and you’ll notice the differences. Rushes (Juncus family) have rounded leaves like tall cylinders; grasses (family Poaceae) usually have hollow stems with conspicuous sheaths where the leaves meet the stems, also called nodes; and sedges (family Cyperaceae, including Carex) have solid, conspicuously triangular stems that lack nodes. The name Carex is derived from keiro, Greek for “to cut,” a reference to the sharp leaf edges that can cut your hand.
More than 2,000 Carex species grow wild in numerous habitats across the world, particularly in New Zealand, Japan, and the United States. This low-maintenance, deer-resistant group is well-suited for a wide range of garden sites including rock gardens and containers, perennial beds, borders, and native-plant gardens. They can also thrive in environments as different as dry shade and boggy areas alongside streams and ponds.
Foliage usually grows in tussocks or tufts of fine-textured or coarse blades, often upright and arching at the tips; some appear to have been tousled by a whirlwind. Leaf color varies from light to medium green, blue-grayish green, bronze, and caramel; many selections are rimmed or edged with contrasting white, silver, or yellow. Because the foliage is more or less evergreen, especially in mild climates, sedges provide much-needed winter interest where not covered by snow. Greenish sedge flowers are seldom large or striking individually (except for Gray’s sedge, C. grayi), but several of them cluster in showy spikes or dense heads to put on quite a display, such as black sedge (C. nigra). Others are inconspicuous, such as weeping brown sedge (C. flagellifera) and blue sedge (C. flacca). Plants either carry male flowers on a part of the plant separate from the females, or females may be separated on the same spike. Fruits that follow are called nutlets.
Cultivation: The recent explosion in popularity of Carex species is due to their great variability and adaptability to so many site conditions. Gardeners have finally realized how useful sedges can be. Planting time varies by species. Generally, cool-weather sedges are best planted in fall. Warm-weather species including New Zealand hair sedge (C. comans), Morrow’s sedge (C. morrowii), brown sedge (C. petriei), and plantain-leaved sedge (C. plantaginea) tolerate either fall or spring planting with success. Leatherleaf sedge (C. buchananii) prefers spring planting.
With more than 2,000 separate species and multiple selections and cultivars, sedges range in height from creeping or prostrate to 4 feet tall or more. Whether in sun or shade, wet or dry, or rocky or fertile soils, sedges adapt to most conditions. Most thrive in soil that remains moist and does not desiccate in the heat of summer. Average garden soil is usually fine, although incorporation of moisture retaining organic matter at planting time is beneficial, as is a summer mulch.
Propagation and maintenance: Increase sedges by dividing the plants in early spring. Usually small plants or plugs are available in local nurseries and garden centers for residential plants. Seed germination may be spotty and generally is only used on a large scale. Maintenance is confined to late spring, after frost is likely. Rake out the old dead leaves from the previous year or cut the tufts back to about 4 inches. Be aware that leatherleaf sedge does not like a haircut and is best just tidied up a bit to expose the new growth.
Appropriate species: Sedges are suitable for almost any place you need to furnish. Some species make excellent groundcover plants. For example, C. morrowii ‘Ice Dance’ seldom tops 15 inches in sun or part shade. For containers or as specimen plants, try eye-catching variegated Japanese sedge (C. oshimensis EverColor ‘Everillo’). Adaptable, easy-care sedges have earned their place in residential gardens. No longer considered substitutes for ubiquitous ornamental grasses, they are appreciated now for understated interest and contrast to showier companions.
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