FIRST IMPRESSIONS: Carex bicknellii is a perennial sedge with a rounded form. In summer triangular leafy stems rise above the tufts of narrow grass-like foliage. The culms bear scaly green oval flower clusters that transition into coppery brown seed heads. This is an upland sedge and one of the few that grows in prairie habitats. Plants thrive in sunny sites with mesic to dry soil.
HABITAT & HARDINESS: Carex bicknellii is native to North America from Manitoba and Ontario south to Maine and Delaware and west to North Dakota and Kansas. The greatest distribution is in the Plains States.
Plants are indigenous to mesic to wet prairies and savannas, barrens, thinly wooded slopes, old fields and roadsides. Plants are usually found in high quality prairie remnants but sometimes occur in sunny disturbed sites.
Hardy from USDA Zones 3-7.
PLANT DESCRIPTION: Carex bicknellii grows from short creeping rhizomes eventually forming rounded clumps. The tufted basal growth is usually about 2’ tall. In summer multiple leafy culms rise to 3’.
The leaf blades are up to 10” long and about 1/8” wide. They are upright, lime green and smooth. Foliage turns green and initiates growth in early spring before the warm season grasses begin to grow.
In late spring each culm is topped by a several ovoid spikelets. The spikelets contain staminate florets on the bottom and pistillate florets at the top. Coppery brown seedheads form around mid-summer.
The flowers and seed-heads are not considered to be showy but the seed are relished by sparrows and gamebirds.
Plants are 1-3’ tall with an equal spread.
CULTURAL & MAINTENANCE NEEDS: This is an upland sedge that prospers in sunny sites with dry, average or moist soil.
Plants tolerate drought, controlled burns and soil disturbance. They should be cut or burned to the ground in late winter.
Like most sedges, this one is pest resistant and fairly unpalatable to deer and other herbivores.
Plants will decline if shaded by aggressive taller companions
LANDSCAPE USES: Carex bicknellii is a useful component of Prairies, Meadows and Rain Gardens. It provides Erosion Control and is appropriate for Groupings or Mass Plantings, Deer Resistant Plantings, Water Wise Landscapes, Low Maintenance Plantings, Restoration Projects and Wildlife Gardens.
COMPANION & UNDERSTUDY PLANTS: Try pairing plants with Eryngium yuccifolium, Rudbeckia subtomentosa, Veronicastrum virginicum, Sporobolus heterolepis and Andropogon gerardii.
Carex molesta.is similar in appearance and cultural needs and can be substituted if needed.
TRIVIA: Carex bicknellii along with the few other prairie dwelling sedges can make up as much as a quarter of the plant residents in a tallgrass prairie,
The perigynium is a distinguishing feature of Carex spp. This is a bag-like bract that encloses the pistillate flower. The sac-like structure persists after fertilization and surrounds the resulting achene seed. The size and surface characteristics of the perigynium are important identification characteristics. Compared to its close relatives (C. molesta & C. brevior), Carex bicknellii has the largest perigynium (about ¼” long and over 1/8” wide), unique brown perigynium margins and translucent epidermis that may allow the dark achene inside to be visible.