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Knotsheath Sedge

Carex retrorsa

Knotsheath sedge is named for what its fruiting spikes do: the individual sacs bend sharply backward and downward as they ripen, so a mature head bristles in reverse — a reliable field character in a genus where identification usually turns on details this small. The spikes crowd together near the top of the stem, often with the lowest one held well below the rest on a long stalk of its own. It is a northern wetland plant, growing in marshes, alder swamps, wet ditches and beaver meadows from New England across the Great Lakes and into the Rockies. Its foliage is a soft yellow-green in a loose upright clump that stays presentable into winter. It is one of the sedges that colonizes disturbed wet ground quickly, turning up in new ditches and drawdown zones ahead of slower species. Sparrows and waterfowl take the seed, and it hosts satyr caterpillars.

Family

Cyperaceae

Type

grass

Lifespan

perennial

Height

1–3 ft

Spacing

1–1.5 ft apart

Light

part shade, shade

Soil moisture

moist

Soil pH

acidic, neutral

Bloom

June, July, August

Bloom colors

green, brown

Wildlife value

songbirds, larval host, mammals

Landscape uses

specimen, border, naturalizing

Native states

CO, CT, IA, ID, IL, IN, MA, ME, MI, MN, MT, ND, NH, NJ, NY, OH, OR, PA, RI, SD, UT, VT, WA, WI, WY