The Perennial Matchmaker

Sedges (Carex) are excellent plants to consider when you’d like the look of an ornamental grass in a site that’s too shady for most true grasses to thrive. They’re useful in many other situations, too: Quite a few can grow in sun, and some are ideal for wet sites. Sedges also offer some outstanding foliage effects that you can’t get from most other perennials.

There are well over 1,000 species of sedges, though only a small fraction of them are readily available to gardeners. That still leaves plenty of options, however. One feature to keep in mind when choosing among them for combinations is whether they are primarily clump forming or creeping.

Clump-forming sedges work well singly as accent plants in combinations, or in groups to fill in larger areas. Some of the most widely available clump formers are 6- to 12-inch-tall plantainleaf sedge (C. plantaginea), for Zones 3 to 8; 6- to 12-inch-tall blue wood sedge (C. flaccosperma), for Zones 5 to 8; and 1-foot-tall Bunny Blue sedge (C. laxiculmis ‘Hobb’), Gold Fountains sedge (C. dolichostachya ‘Kaganishiki’), and Japanese sedge (C. oshimensis; also sold as C. hachijoensis or C. morrowii), for Zones 5 to 9. The 1- to 2-foot-tall Bowles’ golden sedge (C. elata ‘Aurea’) grows in Zones 5 to 9, while the 2- to 3-foot-tall palm sedge (C. muskingumensis) is for Zones 3 to 9. New Zealand sedge species—such as 1-foot-tall New Zealand hair sedge (C. comans), 12- to 18-inch-tall weeping brown sedge (C. flagellifera), and 1- to 2-foot-tall leatherleaf sedge (C. buchananii)—are all for Zones 6 or 7 to 9. They tend to stay in distinct clumps, as does 1- to 2-foot-tall sparkler sedge (C. phyllocephala ‘Sparkler’), for Zones 7 to 9.

Creeping sedges may be a bit too vigorous to pair well with delicate companions but are great co-stars for sturdy perennials, such as medium-size and large hostas, in larger borders. Some sedges that are more likely to spread than to stay in tidy clumps are 6- to 12-inch-tall broadleaf sedge (C. siderosticha) and ‘Ice Ballet’ and ‘Ice Dance’ sedge (often listed under C. morrowii), as well as 10- to 16-inch-tall blue sedge (C. flacca or C. glauca), all for Zones 4 to 9.

The flowers of most sedges are small and not especially interesting, so foliage is the key feature to consider for combinations. Some sedges with solid green leaves include ‘Everdi’ Japanese sedge, palm sedge, and plantainleaf sedge. These and other all-green sedges are easy to combine with any flower color and are excellent as “neutral” additions to combinations that already include bright yellow or showily variegated foliage.

There are many variegated sedges, too. Some are on the subtle side: ‘Ice Dance’, for instance, has thin white leaf edges, and ‘Island Brocade’ sedge is narrowly edged with yellow. They’re elegant up close, but you may not notice their understated markings from a distance. The pinstriping on the superslender leaves of Japanese sedge selections, such as Everest (‘Carfit01’), with bright white edges, and ‘Evergold’, with creamy yellow centers, and on Gold Fountains sedge, with yellow edging, also shows up best in combinations that you see at close range. For more dramatic markings, consider sparkler sedge, ‘Spark Plug’ (its more-compact version), or ‘Snow Cap’ broadleaf sedge, all with white edging, or bright-yellow-and-green ‘Banana Boat’ broadleaf sedge. All of these are ideal for repeating the variegated foliage of hostas and other larger-leaved or taller partners, for echoing the blooms of white- or yellow-flowered companions, and for adding a bit of zip among ferns and other green-leaved bedmates.

Sedges with bright yellow leaves are especially striking color accents in combinations. Bowles’ golden sedge is actually variegated, because its foliage has a thin green edge, but it looks solid yellow even at fairly close range. Some other particularly good choices here are solid yellow ‘Everillo’ Japanese sedge and ‘Lemon Zest broadleaf sedge. All of these are terrific with flowering partners in shades of blue and purple, such as ‘Big Blue’ and ‘Caesar’s Brother’ Siberian irises (Iris sibirica). The yellow sedges pair well with pinks, such as ‘Ostrich Plume’ astilbe (Astilbe); reds, such as ‘Ruby Wedding’ masterwort (Astrantia major); and oranges, such as candelabra primrose (Primula bulleyana).

For foliage companions to yellow sedges, consider dark green partners, such as Lenten roses (Helleborus × hybridus); deep purples to blacks, like those of black mondo grass (Ophiopogon planiscapus ‘Nigrescens’) and ‘Ravenswing’ cow parsley (Anthriscus sylvestris); yellow variegates, such as variegated meadowsweet (Filipendula ulmaria ‘Variegata’); and blues, such as ‘Blue Mouse Ears’ or ‘Love Pat’ hostas.

Speaking of blues: There are some splendid blue-leaved sedges, including blue wood sedge, ‘Blue Zinger’ blue sedge, and Bunny Blue sedge. Pair them with white or pastel blooms, like those of columbines (Aquilegia), or with other blue, gray, or silver leaves, like those of ‘Halcyon’ hosta or ‘Majeste’ pulmonaria (Pulmonaria). They also partner with rich green foliage, like that of bergenias (Bergenia) or European wild ginger (Asarum europaeum), or with bright yellows, such as ‘Sun King’ Japanese spikenard (Aralia racemosa).

The leaves of New Zealand sedges offer some particularly distinctive color options: shades of copper and bronze, often with some touches of pink, if you look closely. They make a great front-of-the-border echo for the seed heads (and winter color, too) of many ornamental grasses, including feather reed grasses (Calamagrostis). Use them to pick up the colors in orangey-leaved heucheras, such as ‘Caramel’, or peachy to bronzy blooms, like those of ‘Copper Classic’ bearded iris, Lady of Shalott rose (Rosa ‘Ausnyson’), ‘Milk Chocolate’ daylily (Hemerocallis), or sunset hyssop (Agastache rupestris). Or make intriguing combinations by pairing them with purples, like the leaves of ‘Purple Emperor’ sedum (Sedum) or the blooms of ‘Wood’s Purple’ aster, or with partners that have bright yellow foliage, such as ‘Angelina’ sedum (Sedum rupestre) or ‘Aztec Gold’ prostrate speedwell (Veronica prostrata).

Most common sedges have a mounded or tufted form. For contrast, set them among even shorter, carpet- or mat-forming companions, such as spotted deadnettle (Lamium maculatum) or woodland sedum (S. ternatum), or in front of taller, upright perennials, such as ‘Ghost’ lady fern (Athyrium).

Sedge leaves are typically long and narrow, giving the plants a fine, grassy texture that’s excellent for adding visual variety to combinations with larger leaves, like those of hostas and ligularias (Ligularia). Sedges with arching leaves, such as Japanese sedge, New Zealand hair sedge, and plantainleaf sedge, contrast with irises and other spiky partners. Those that are spiky themselves, such as broadleaf sedge, palm sedge, and sparkler sedge, contrast with companions that have broad or rounded foliage, such as heucheras (Heuchera) and Siberian bugloss (Brunnera macrophylla).

Sedges are valuable for foliage texture and color all through the growing season, or even longer. For early color around deciduous species—those that die back to the ground over winter, such as Bowles’ golden sedge, broadleaf sedge, and palm sedge—use early-blooming bulbs, such as snowdrops (Galanthus) and winter aconite (Eranthis hyemalis).

Many other sedges can be ideal for four-season interest, depending on where you live. The New Zealand sedges tend to keep their color all year long, for instance, as do ‘Ice Ballet’ and ‘Ice Dance’, Japanese sedge, Gold Fountains sedge, and the blue-leaved species and selections, so they can be superb with other perennials that have persistent foliage, such as Allegheny pachysandra (Pachysandra procumbens), bergenias, and hellebores (Helleborus). These “evergreen” sedges may get winter damaged in the cooler parts of their growing ranges, though, especially when snow cover is lacking, so you may end up needing to trim off the browned tips or shear them an inch or two above the ground in early spring to make room for fresh new leaves.

Bloom Buddies

Marvelous Matches for Flowering Combos

Sedges (Carex) have a reputation for liking shade and moisture, but that doesn’t apply to all species, so it’s important to check their preferences before choosing companions. Below is just a sampling of the many terrific flowering partners that can pair well with these top-notch foliage perennials.

Companions for full sun to light shade and average to moist but well-drained soil (with New Zealand sedges, such as C. buchananii, C. comans, and C. flagellifera):

Agastaches (Agastache)

Asters (Aster)

Carolina phlox (Phlox carolina)

Coreopsis (Coreopsis)

Heleniums (Helenium)

Heucheras (Heuchera)

Irises (Iris)

Meadow phlox (Phlox maculata)

Purple coneflower (Echinacea purpurea)

Sedums (Sedum)

Summer phlox (Phlox paniculata)

Yarrows (Achillea)

Companions for full sun and moist soil or partial shade and average, well-drained soil (with blue sedge [C. flacca], Bowles’ golden sedge [C. elata ‘Aurea’], Gold Fountains sedge [C. dolichostachya ‘Kaga-Nishiki’], and palm sedge [C. muskingumensis]):

Astilbes (Astilbe)

Candelabra primrose (Primula bulleyana)

Hostas (Hosta)

Japanese iris (Iris ensata)

Japanese primrose (Primula japonica)

Ligularias (Ligularia)

Meadowsweet (Filipendula ulmaria)

Perennial lobelias (Lobelia)

Rodgersias (Rodgersia)

Siberian iris (Iris sibirica)

Turtleheads (Chelone)

Companions for partial to full shade with average to moist but well-drained soil (with blue wood sedge [C. flaccosperma], broadleaf sedge [C. siderosticha], Bunny Blue sedge [C. laxiculmis ‘Hobb’], ‘Ice Dance’ and ‘Ice Ballet’ sedge, Japanese sedge [C. oshimensis], plantainleaf sedge [C. plantaginea], and sparkler sedge [C. phyllocephala ‘Sparkler’]):

Bleeding hearts (Dicentra)

Columbines (Aquilegia)

Epimediums (Epimedium)

Foamflowers (Tiarella)

Foamy bells (× Heucherella)

Pulmonarias (Pulmonaria)

Spotted deadnettle (Lamium maculatum)