FIRST IMPRESSIONS: Carex radiata is a diminutive perennial sedge that forms dense tufts of narrow foliage. The leaves are light green and semi-evergreen. In late spring green star-shaped clusters of flower spikelets are displayed above the foliage. This sedge occurs in part shade to partly sunny woods in moist to mesic soil. It also has great landscape potential as a woodland groundcover or lawn substitute.
HABITAT & HARDINESS: Carex radiata is native to eastern North America from Nova Scotia to Georgia and west to Manitoba and Arkansas.
Plants are indigenous to moist to mesic deciduous forests, moist oak woods, slopes of shady ravines, edges of shaded seeps, seasonally wet woods and disturbed woods.
Hardy from USDA Zones 4-8.
PLANT DESCRIPTION: Carex radiata grows in compact clumps of delicate arching foliage. The crown expands to form larger clumps but this sedge is not noticeably rhizomatous.
Leaves are medium green and about 1/16” wide. The narrow blades are evergreen through most of the range.
In spring upright culms bear 4-8 rounded star-like spikelets that are widely spaced rather than clustered. The terminal spikelet contains both staminate and pistillate florets. The lower spikelets have only pistillate florets.
The spikelets look somewhat like green starbursts due to the presence of 3-8 spreading perigynia. Each pistillate floret within the perigynium has two threadlike rosy pink straight or slightly twisted stigmas that protrude from the top.
This sedge is 1-2’ tall with an equal spread.
CULTURAL & MAINTENANCE NEEDS: Carex radiata prospers in moist or average woodlands. The preferred exposure is dappled sunlight or part shade. Plants will tolerate full shade but may flop and be slow to cover the ground.
Established plants are drought tolerant, pest resistant and unpalatable to deer and other herbivores.
In garden situations, plants should be cut to the ground during late winter before new growth is initiated.
LANDSCAPE USES: Carex radiata is a valuable Groundcover or Edging Plant for a Shade Garden. This sedge is lovely when Grouped or Massed with spring wildflowers and is reported to be a good Lawn Substitute. The unique leaf texture allows this sedge to serve as an eye catching Accent. Plants provide Erosion Control and Winter Interest and are appropriate for Deer Resistant Plantings, Low Maintenance Plantings, Rain Gardens and Wildlife Gardens.
This sedge is an excellent native substitute for the popular Asian groundcovers Liriope muscari and Ophiopogon japonicus.
COMPANION & UNDERSTUDY PLANTS: Suitable garden companions for Carex radiata could include woodland wildflowers and ferns like Antennaria neglecta, Chrysogonum virginianum, Heuchera americana ‘Dale’s Strain’, Iris cristata, Phlox divaricata, Spigelia marilandica, and Polystichum acrostichoides.
This species is similar in appearance and cultural needs to Carex roseq, Carex appalachica and Carex pensylvanica.
TRIVIA: Carex rosea is very similar to Carex radiata. The two often grow in the same woodlands but C. rosea is found in drier sites with Quercus alba, Q. rubra or Q. macrocarpa. Carex radiata is found in wetter sites often with Quercus bicolor. C. rosea has thicker red coiled stigmas. C. radiata has slender straighter red stigmas.