Sedgescaping: they share the space unselfishly

“They share the space unselfishly.” “Sedges give you the opportunity to outsmart weeds.”

Roy Diblik
Image result for It is in a subordinate plant amid showier blooms and specimens that sedges get their power, tying a landscape together. Here Pennsylvania sedge is planted with violet wood sorrel. (George Coombs/Mount Cuba Center)
Pennsylvania sedge with violet wood sorrel (George Coombs/Mount Cuba Center)

Why create a sedgescape

Roy Diblik, through his nursery Northwind Perennial Farm, is a strong advocate for using sedges.

Think of the sedge or carex family as an early-season grass that looks good all summer. Not only do carex look good, they’re durable, adaptable plants that enhance the health of an entire plant community. 

  • Dense, fibrous root systems hold a lot water. Up to 1/3 of these roots die every year, decomposing to add moisture and nutrients to the soil and storing carbon
  • Drought tolerant if you choose the right sedge for the right place
  • Provide cover, nesting sites and nesting material for birds and small mammals
  • Nectar and pollen source, larval host for some pollinators (Pennsylvania sedge, feeds as many as three dozen species of caterpillars)
  • Many kinds of wildlife (including birds) eat the seeds
  • Disease and pest issues rare
  • Many are evergreen, offering winter colour
  • Green in early spring when other perennials are still dormant
  • Some have interesting seedheads
  • No need to fertilize
  • Hundreds of native sedges, one for every soil type and site condition
  • No need to mow 
  • Deer don’t eat them (though rabbits enjoy a few varieties)

How to design using sedges

With over 2,000 varieties of sedge (200+ native to Ontario), there is a sedge for almost every ecosystem and design. Some are tiny. Others are over a metre tall. Some creep. Others clump. Some like it wet. Others like it dry. Many prefer shade, but some like sun and others thrive in either sun or shade.

Edging with sedges (thriving despite almost two months of drought). Over time wild strawberry, barren strawberry and violets will fill in the gaps. This unidentified non-native sedge will also slowly spread by rhizomes.

Underplanting trees and shrubs with carex

Instead of mulching trees and shrubs with shredded bark, underplant with sedges as a living green mulch to cover bare soil and fill gaps. Sedges have a dense root system that holds water like a sponge, helping to keep the tree hydrated. And each year, as some of their roots die, they improve the moisture holding capacity of the soil. 

Common Wood Sedge (Carex blanda) with Virginia Bluebells (Mertensia virginiana), Jacob’s Ladder (Polemonium reptans), and Red Trillium (Trillium recurvatum) growing under a Hackberry (Celtis occidentalis) at the Chicago Botanic Garden

Replacing a lawn with a carex matrix 

George Weigel, Pennsylvania sedge (Carex pensylvanica) makes a good no mow lawn substitute

Sedges make a great lawn alternative, especially in tough spots like dry shade. While a few sedges such Pennsylvania Sedge (Carex pennsylvania) and Appalachian sedge (Carex appalachica) work as a lawn-like groundcover (how to plant a sedge lawn), most sedges aren’t aggressive enough to out compete weeds.

For great biodiversity and resilience consider combining different sedges in a matrix design. You can experiment with a Carex community composed of several compatible sedges or interplant sedges with perennials. For more background on designing a carex community, get a copy of Roy Diblik’s wonderful book Know Maintenance Perennial Garden

Roy Diblik, Northwind Perennial Farm

Carex matrix, foundation or base layer

In a diverse plant community or meadowscape, you can use sedges in a design that weaves in between other plants to tie everything together. This creates a more resilient design that keeps out weeds. – creating a more resilient design. This use of sedge is known as matrix, foundation or base planting.


Roy Diblik, Know Maintenance Perennial Garden, fern and carex matrix with bulbs for early spring colour

Sedges for every situation

Two unidentified varieties of sedges seeded themselves beside a black walnut

According to the National Heritage Information Centre species list, there are 248 species belonging to the Carex genus– the sedges, in Ontario. Here are some you may find at local or mail order nurseries. Two useful resource for choosing sedges to match site conditions are the comparison charts from Hoffman Nurseryand Prairie Moon Nursery.

Carex appalachicaAppalachian sedgeDrought tolerant lawn substitute, native to dry woods, dense mounded tufts
Carex aureaGolden sedgeNative to moist to wet shores, pale green to yellow foliage, small green blooms in June ripen to edible light brown seeds mid summer, 10-15 cm, moist to wet soil
Carex bicknellibicknell’s sedgeNative to dry prairies and slopes, drought tolerant sedge, good vertical accent, 60-90 cm
Carex bromoidesBrome sedgeGraceful native sedge, but not drought tolerant
Carex breviorfescue sedgeNative sedge, Roy Diblik pairs with Stachys officinalis ‘hummelo’
Carex flaccaBlue sedgeNaturalized, drought tolerant, grows in diverse habitats, spreads by rhizomes, good ground cover
Carex greyiGray’s sedgeShort (5 cm) native sedge prefers light shade, bold texture, chestnut sized, green flowered spiked seedheads resemble a mace
Carex griseawood sedgeNative sedge, foliage lasts throughout winter, reseeds itself, tolerates wide range of soil
Carex laxifloraLoose-flowered sedgeNative to rich, deciduous woods & meadows, 60-90 cm, distinctive, wide-leaved, tussock-forming sedge with pale green leaves and seed heads makes a good companion to many spring-blooming woodland wildflowers
Carex muskingumensswamp sedgeNative to low woods and wet meadows, tall (60-90 cm) sedge resembles a small palm tree, drought tolerant if in partial shade. Large dense root system makes it great for rain gardens.
Carex pennsylvaniaPennsylvannia sedgeNative to open woodlands, colony forming drought tolerant sedge makes a good lawn substitute, good under ferns and low growing shade perennials
Carex plantagineaPlaintain sedgeNative, semi-evergreen woodland sedge, great companion for native ground covers, works well in a sedge matrix
Carex shortiaShort’s sedgeNative architectural sedge, flower spikes stand throughout summer
Carex sprengeliiLong-beaked sedgeNative to moist deciduous woods, upright slightly arching, 60-90 cm, dense clumps, messy looking in June
Carex swaniiDowny green sedgeNative to dry to wet mesic forests, 30-90 cm, prefers consistent moisture, Roy Diblik says pairs well with salvia

Caring for sedgescapes

Unlike traditional lawns, sedgescapes need little maintenance. In late spring, once overwintering insects have emerged from hibernation, you can cut the tufts back if you’d like. If you do, leave the cuttings beside the plants to decompose and feed the soil. You can also divide your sedgesif you want to make more plants. 

References

Sources