Sedges for the Landscape

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Noteworthy plants in natural areas can be the superstars of landscaping when gardeners learn to harness their natural tendencies and display their most virtuous attributes.  One group of plants that I have often underestimated are sedges (Carex spp.). 

These tough native perennials have a grass-like appearance and interesting flower structures from tiny tufts to spikey balls.  While they appear similar to grasses, there are several differences between each group of plants, with the main distinction being the sedge’s angular stems which contrast with the rounded stems of grass species.  And thus, many apply the common identification mantra “sedges have edges” in reference to the shape of their stems. 

Rosy sedge paired with tulips and other spring wildflowers
Rosy sedge is native woodland plant with thin, narrow leaves. It creates a spectacular display when grouped with spring wildflowers as pictured here in the Red Oak Rain Garden on UIUC Campus. Photo by Layne Knoche, Illinois Extension.

When I think of sedges in nature, I usually think of wetland ecosystems, but the genus Carex is incredibly diverse with species inhabiting nearly all ecosystems on earth.  In fact, over 150 species are native to Illinois.  So, there truly is a sedge for any situation. 

As landscape plants, sedges thrive in an equally diverse array of site conditions.  Many of the species commonly employed in the built environment are hardworking generalists in nature.  They’re plants that thrive in a range of conditions, which lends well to meet the demands of urban plantings.

Pennsylvania sedge (C. pennsylvanica) is one of the most common species that I see in cultivation.  Its claim to fame is the ability to handle dry soil conditions with full shade.  With a shorter stature, rarely exceeding 1 ft tall, this hardy perennial is an excellent plant for shade gardens, interspersed with ferns.   It’s incredibly fine texture accents the more coarse foliage of ferns and it can tolerate very heavy shade.  It can be a wonderful ground cover, spreading by rhizomes to create a carpet of thin, feathery leaves.  I have also seen it used a low-maintenance alternative to turf grass, only requiring mowing 2-3 times per year. 

Rosy sedge (C. rosea) is another shorter species that boasts great versatility in the landscape.  It’s best suited to shade, but I have seen it growing in full sun out in nature.  It can tolerate just about any soil conditions from dry to very wet.  Foliage is a deep green color and very fine-textured making it another wonderful accent plant to be placed among other more coarse-textured or taller perennials.  Across most of its native range, this plant is evergreen, maintaining green foliage throughout the winter season.  When combined with plantings of spring wildflowers, rosy sedge provides wispy carpet of green to frame the emerging, early-season blooms.

For wetter sites or rain gardens, I have really come to appreciate swamp oval sedge, also known as palm sedge (C. muckingumensis).  This plant does well in sun or shade and can reach heights of almost 3 ft when allowed full sun exposure.  It tolerates soil compaction and clay soils very well, making it a great addition to problematic wet areas.  The attractive, bright green foliage has a more coarse appearance with larger leaves that are densely arranged along its triangular stems to create its unique texture.  This plant also offers fall color as it transitions to golden yellow.

I have really enjoyed plantings of palm sedge at the edge of ponds or stream banks.  It works wonderfully in rain gardens where its unique arching foliage can help to accentuate hardscaping such as drainageways or rock-lined inlets.  Its stiff stems also help to slow down incoming runoff and reduce its erosive energy.         

If you are interested in adding native plants like sedges to your landscape this year, Grand Prairie Friends is once again hosting their annual native plant sale.  The plant list for this year’s sale has over 50 species of native plants offering a plethora of interesting foliage and beautiful blooms.   In addition, all the plants on this list support our native wildlife species and help to diversify both plant and animal life in your neighborhood.  All sales will be handled online this year, with the online store scheduled to open at 8am on May 1st and plant pick up the week of May 16 in Urbana.  Please visit the Grand Prairie Friends website for more information at: www.grandprairiefriends.org.