Robert H. Mohlenbrock. USDA SCS. 1989. Midwest wetland flora: Field office illustrated guide to plant species. Midwest National Technical Center, Lincoln. Courtesy of USDA NRCS Wetland Science Institute, USDA-NRCS PLANTS Database
FIRST IMPRESSIONS: Carex molesta is a versatile perennial sedge of prairies, disturbed areas and wetlands. In summer triangular leafy stems rise above low tufts of narrow grass-like foliage. The culms bear prickly green spherical spikelets that transition into golden brown seed clusters. This sedge flourishes in sunny wet sites.
HABITAT & HARDINESS: Carex molesta is native to Ontario, Quebec and in most of the eastern United States. Plants occur from New York to Virginia and from North Dakota to Kansas
Plants are indigenous to wet or mesic prairies, open woodlands, swamps, wet fields, ditches and other disturbed sites.
Hardiness exends from USDA Zones 3-8.
PLANT DESCRIPTION: Carex molesta grows in low bunches from short creeping rhizomes. Leaf blades are usually about 1’ long and 1/8” wide.
In late spring multiple leafy culms rise above the foliage to 2-3’. Each culm bears 2-5 rounded flower spikelets that are clustered closely together. Each of the green spikelets contains upper pistillate and lower staminate florets. The spikelets are rounded at top and base and contain many perigynia. The flowers transition into reddish brown summer seed spikes.
Plants are 2' tall with an equal spread.
CULTURAL & MAINTENANCE NEEDS: Carex molesta prospers in sunny or partly sunny sites with average to wet soil. Plants tolerate drought and soil disturbance.
This sedge seems to tolerate difficult disturbed sites better than closely related native sedges. Plants conquer adversity as their short rhizomes expand to form colonies and seed successfully germinate.
In garden or prairie situations, plants can be cut or burned to the ground in late winter.
This sedge is pest resistant and fairly unpalatable to deer and other herbivores.
LANDSCAPE USES: Carex molesta is a useful component of Prairies, Meadows and Rain Gardens. It provides Erosion Control and Stormwater Management and is appropriate for Groundcover or Mass Plantings, Deer Resistant Plantings, Water Wise Landscapes, Low Maintenance Plantings, Roadsides, Restoration Projects and Wildlife Gardens.
COMPANION & UNDERSTUDY PLANTS: Try pairing plants with Asclepias syriaca, Aster oblongifolius, Eryngium yuccifolium, Sporobolus heterolepis and Andropogon gerardii.
Carex brevior is similar in appearance and can be substituted if needed.
TRIVIA: Carex molesta 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 peculiar specific epithet molesta means troublesome. Some say the name was attached to this plant due to its invasive nature. Others say that the name is due to the difficulty in sorting out the Ovales group of sedges to which this one belongs.
Carex molesta is very similar to the closely related Carex brevior. To differentiate between the two, examine the shape and arrangement of the spikes. C. brevior has oval spikes with a tapered base that are arranged on the culm with space between while C. molesta has globular spikes with a rounded base that are packed close together. The perigynia are sacs that enclose the pistillate flowers and seed. C. brevior has flat rounded perigynia with nerves or veins and C. molesta has rounded perigynia without nerves.