The Sedge Alternative
Sedges are gaining increasing recognition as a native alternative to nonnative groundcovers such as English ivy (Hedera helix), wintercreeper (Euonymus fortunei), and periwinkle (Vinca minor and V. major). These commonly used nonnative groundcovers have escaped their intended confines and become invasive in many natural areas. Sedges are also an excellent substitute for turf as we struggle to maintain a green home landscape without the dependence on fertilizers, herbicides, and extra watering required for lawns. Properly selected native groundcovers (right plant, right place) require the least amount of maintenance because they establish quickly, are long-lived, suppress weeds, and require little mulch once established.
Although this article will concentrate on sedges, let’s first identify the broader categories of “grass-like” plants. We will look at the differences among sedges, rushes, and ornamental grasses. Lastly, we’ll consider liriope, a frequently used nonnative groundcover that could be confused with the above genera.
Even horticulturalists who specialize in grass-like plants point out the difficulties in identifying different species. A distinguishing characteristic is the stem structure. A common rhyme is useful: Sedges have edges; rushes are round; grasses have nodes all the way to the ground.
- Sedge, a grass-like perennial plant with triangular stems and inconspicuous flowers, grows in a variety of habitats (often moist to wet areas) throughout the world. Of the family Cyperaceae, there are over 1500 species of the genus Carex, which from Latin means “cutter” in reference to the sharp leaves and stem edges. Identification of individual species can be very difficult. Seed heads are located at the end of the stem and are wind pollinated. Sedges have fibrous root systems, and some produce rhizomes.
- Rush, a member of Juncaceae family, is an erect, tufted marsh or waterside plant with inconspicuous greenish or brownish flowers resembling a sedge or a grass. A few are annuals, but most are perennials. Rushes are slow-growing and spread by rhizomes. There are two main genera, Juncus (the largest genus) and Luzula (wood rushes). Juncus members have hairless, cylindrical stem-like leaves; Luzulu members have hairy, grass-like leaves. Widely distributed in temperate areas, some rushes are used for matting, chair seats, and baskets.
- Grasses are of the family Poaceae and have hollow cylindrical stems. The stems of sedges and rushes are generally solid. Grass stems also contain swollen nodes or joints; sedges and rushes do not. Grasses can be either annual or perennial. Grasses will tend to grow in two ways — as clumps that get thicker and wider, or as a spreading mass which sends out rhizomes (below ground) or stolons (above ground) to colonize any available ground. Some ornamental grasses, such as Northern Sea Oats, produce viable seed, but many do not. For more information on different types of grasses and their uses in the landscape, see “Ornamental grasses: easy, beautiful and – invasive?”
- Lirope, of the Liliaceae family, is native to China, Taiwan, and Japan. Often called lilyturf, this evergreen ground cover produces showy lavender, purple, pink or white flower spikes in July and August. Clusters of bluish-black, berry-like fruit follow the flowers. Liriope is remarkably tough and can grow in deep shade or full sun, in sandy or clay soils. Although it requires good drainage, it can endure heat, drought and salt spray. There are two major species: big blue lilyturf (Liriope muscari) and creeping lilyturf ( spicata). L. spicata spreads rapidly by underground stems (rhizomes). Both species form mounds of grass-like foliage. Usually the foliage is dark green, but in some varieties it is variegated. There are many different cultivars of liriope.
Sedges thrive in many different sunlight and soil conditions. Some can be grown in deep shade or full sun, on dry slopes or in standing water. Some are more grass-like in appearance while others have wider leaves (to 1”). They can be massed as lush green groundcovers, reducing the need for mulch. Some can be used in place of turf, reducing lawn maintenance. They can be used as specimen plants in ornamental gardens, or in rain gardens. Foliage comes in bright green, lime green, or blue green.
Native Host Plants
Using native plants in landscaping promotes biodiversity which supports plant and wildlife conservation. As noted in the Carex descriptions that follow, various native sedges act as caterpillar hosts plants for moths and butterflies.
Carex flowers are generally subdued spikes in shades of tan or green that appear in spring before dense foliage growth kicks in. Some flowers fade to become attractive tawny seed heads that billow above the foliage. In the following brief descriptions, I have noted only those flowers that seem to be considered “showier,” although even these sedges are generally grown for the foliage, not the flower.
- C. albicans, white-tinged sedge, used frequently because it tolerates part-shade/sun and dry-to-moist soils. This species tolerates dry soil conditions better than most species of Carex. Grows in clumps 15-20” tall with narrow, grass-like, upright-arching, bright green leaf blades. Best grown in groups or massed for foliage effect. Effective as a ground cover; can be used as a turf alternative. Plants spread slowly by rhizomes and will self-seed in optimal growing conditions. Not listed as deer resistant.
- C. cherokeensis, Cherokee sedge, grows in medium-to-wet soils in full sun to part shade. It thrives in moist soils, but also may do well in average garden soils. It forms attractive, slowly-spreading 6-12” tall clumps with fine-textured, narrow, grass-like, deep-green leaves. Wheat-like seed spikes mature in autumn. Mass or group in open woodland gardens, borders, or rock gardens. It is also an effective accent plant for smaller gardens. Deer resistant.
- C. flaccosperma, blue wood sedge, is easily grown in medium-to-wet soils in part-to-full shade. It thrives in moist soils, but also does well in average garden soils and will tolerate some drought. Forms attractive 6-10” tall clumps of fine-textured, narrow, grass-like, glaucous, blue-green leaves (to 3/8” wide). Tolerates deer and heavy shade.
- C. flaccosperma var. glaucodea, blue wood sedge, is more typically found in drier acidic soils of wooded slopes, upland ridges, ravines or wooded valleys along streams.
- C. grayi, gray sedge, grows best in moist fertile soil in full sun, but will tolerate light shade. It thrives at or near water. It grows 2-3’ tall with greenish yellow to brown seed heads that look like spiked clubs. The grass-like leaves, which are up to 1/2″ wide, are semi-evergreen. Deer resistant.
- C. laxiculmis, creeping sedge, is an evergreen sedge that grows in medium-to-wet soils in part-to-full shade. Soils should not be allowed to dry out, and this sedge needs consistent supplemental watering in hot summer. It typically grows in a dense rounded clump to 12” tall with grassy blue-green leaves up to 1/2” wide. Deer resistant.
- C. laxiculmis ‘Hobb’ BUNNY BLUE is a silvery-blue-leaved cultivar that typically grows in a dense rounded clump to 12” tall with grassy leaves to 1/2” wide. Deer resistant.
- C. lurida, sallow sedge, grows best in wet-to-moist soil in full sun to partial shade. Its grass-like leaves grow up to 3′ tall from short stout rhizomes. The seedheads resemble small sweetgum balls but do not grow above the foliage. Although this sedge does not go dormant in summer, it may require supplemental watering if planted in dry areas. Deer resistant.
- C. muskinomensis is commonly called palm sedge because the leaves superficially resemble miniature palm fronds. This dense, clump-forming sedge produces rigid, erect stems to 20″ tall with 8″ long, pointed, grass-like, light green leaves radiating from the stem tops. It is easily grown in average, medium-to-wet soil in full sun to part shade, although it tends to flop in too much shade. It prefers constantly moist, fertile soil, but will grow in shallow water (3-4″ deep). If grown away from water, soil must not be allowed to dry out. Plants slowly naturalize by rhizomes in optimal growing conditions and may also self-seed. Foliage promptly turns yellow after frost. Cut plants to the ground in winter. Deer resistant.
- C. pensylvanica, Pennsylvania sedge, is used as a lawn substitute for dry soils in shady areas. This low sedge grows in a clump to 8″ tall and is typically semi-evergreen in moderately cold winter climates. Soft, delicate, arching leaves to 1/8″ wide form a turf that never needs mowing, or can be mowed 2-3 times a year to 2″ tall. Often found in areas with oak trees, this plant is also known as oak sedge. It spreads by rhizomes and may sometimes self-seed in optimal growing conditions. It is not a low maintenance choice for garden beds because it tends to outgrow other herbaceous plants. It is a caterpillar host plant for skippers. Not listed as deer resistant.
C. plantaginea, seersucker sedge or plantain-leaf sedge, is a petite perennial woodland sedge with 1’ clumps of striking lime-green, somewhat puckered foliage. Its semi-evergreen leaves are broader (1”) than many other sedges, and they emerge from maroon-colored leaf sheaths. This sedge prefers partly shaded, moist, fertile woods but will tolerate dry, shaded sites. Plants slowly colonize from short rhizomes and produce occasional seedlings. When grouped, this sedge makes an effective ground cover or border for woodland trails. It is a caterpillar host plant for skippers. Deer resistant.
- C. stricta, tussock sedge, is easily grown in moist-to-wet soils including standing water in full sun to part shade. It grows well in wet low spots, water margins, and areas that experience some seasonal flooding. It spreads by rhizomes to form large colonies of dense clumps 1-3′ tall. Older leaves turn straw brown as they die, and build up around the base of each clump; newer leaves are yellowish-green. Flora of North America reports that plants grown in sites with seasonal flooding form distinctive large clumps, and plants grown in drier areas tend to spread more by rhizomes. This sedge is a caterpillar host plant for the Appalachian brown butterfly (Satyrodes Appalachia), Mulberry Wing, (Poanes massasoit), and Eyed Brown butterfly (Satyrodes eurydice). Deer resistant.
- C. vulpinoidea, fox sedge, grows well in damp to very wet soils in full sun to partial shade. Narrow grass-like leaf blades grow in clumps up to 3’ in height. The seedheads, which spray out attractively from the center of the clump, resemble a fox’s tail but are short-lived. This sedge may be weedy and spreads rapidly. It is useful for water gardens or for locations that remain moist near streams, springs, or ponds. Deer resistant.
Summary of Sedge Characteristics and Uses
- C. flaccosperma
- C. albicans
- C. pensylvatica
- C. plantaginea
Wet Soil or Rain Gardens:
- C. grayi
- C. laxiculmis
- C. lurida
- C. muskinomensis
- C. stricta
- C. vulpinoidea
- C. albicans
- C. pensylvanica
- C. albicans
- C. flaccosperma var. glaucodea
- C. pensylvanica
- C. plantaginea
Yellow nutsedge, Cyperus esculentus, is a common lawn and garden weed. The leaves are bright green and have a waxy appearance. It grows faster than many lawn grasses so it is often noticed when it outgrows the surrounding grass. The plant is perennial, reproducing by seed and underground tubers. The underground tubers or nutlets can remain dormant in the ground for several years.
Plant Finder, Missouri Botanical Garden, http://www.missouribotanicalgarden.org/plantfinder/plantfindersearch.aspx
“Ornamental Grasses,” https://extension.illinois.edu/grasses/understanding.cfm
“Ornamental Grasses: easy, beautiful and – invasive?” https://piedmontmastergardeners.org/article/ornamental-grasses-easy-beautiful-and-invasive/
“Ornamental Grasses,” https://web.extension.illinois.edu/dmp/palette/090215.html
“Comparison of grass structure with rushes and sedges,” http://www.countrysideinfo.co.uk/grass_id/intro.htm
Liriope, Clemson Cooperative Extension Home and Garden Information Center, https://hgic.clemson.edu/factsheet/liriope/
Landscaping With Native Plants, A Gardener’s Guide for Missouri, Chapter Four, p.11., Missouri Botanical Garden
Carex plantaginea, http://www.newmoonnursery.com/plant/Carex-plantaginea
Caterpillar host plants, Bringing Nature Home, Douglas W. Tallamy.
Caterpillar host plant for Mulberry Wing, https://www.butterfliesandmoths.org/species/Poanes-massasoit
Caterpillar host plant for Eyed Brown, https://www.butterfliesandmoths.org/species/Satyrodes-eurydice
Caterpillar host plants for skippers, The Living Landscape, Rick Darke and Douglas W. Tallamy.
Green Spring Gardens, www.fairfaxcounty.gov/parks/green-spring/gardening
Native Ornamental Grasses and Sedges for Gardens and Meadows in the Washington D.C. area, Green Springs Garden, Fairfax County, VA
Using Native Plants to Attract Butterflies, Moths, Bees, and other Pollinators in the Washington D.C. area, Green Springs Garden, Fairfax County, VA
“Native Sedges for the Home Garden,” Master Gardeners of Northern Virginia, https://mgnv.org/2018/03/08/native-sedges-for-the-home-garden/