How to Plant and Grow Sedge

Sedge is a grass-like plant that sways in the wind and pairs nicely with coarse-texture plants such as hostas. This tough and versatile plant acts as a groundcover, filling in around other perennials and eliminating the need for mulch. Some native sedges can even be used as lawn replacement.

It grows in silvers, soft blues, golds, reds, and everything in between, even an attractive brownish bronze. Many of the straight species of sedge are a light green color, which works well as a backdrop plant. Along with the attractive foliage, many sedges have small, spiny seed heads lending even more textural interest. Sedge provides shelter and food for small animals and pollinators.

Where to Plant Sedge

Given the huge variety of sedges and their adaptability to different light and soil conditions, there are very few locations where you cannot plant sedges. Soggy, water-logged soil is one of them. Also, let the growth habit of the sedge guide your selection of the planting site. Many of the native sedges growing in the United States are great for filling in between other plants because they can be fairly vigorous spreaders by underground rhizomes. Other types are clump-forming and will stay put no matter where they are.

How and When to Plant Sedge

The planting time varies by species. Generally, cool-season sedges, which include many of the native sedges, are best planted in the fall. Warm-season species including New Zealand hair sedge, Morrow's sedge, brown sedge, and plantain-leaved sedge tolerate either fall or spring planting with success. Leatherleaf sedge prefers spring planting.

Dig a hole about 6 inches wider than the nursery container and no deeper than the depth of the container. Place the plant in the hole and make sure the root crown is slightly above soil level. Backfill the hole with soil and gently tamp it down. The top of the root ball should still be visible and slightly higher than soil level.

Sedge Care Tips

Light

There are sedges for all light conditions, from full sun to partial shade and shade. Some types can handle both sun and shade.

Soil and Water

Some sedges like evenly moist soil while others handle droughts well. One thing all sedges have in common is that they don't tolerate wet soil. Waterlogged soil can cause sedges to rot. Be consistent with your watering, whether it's on the dry side or the wet side because sedges can become stressed from constant fluctuations of moisture. In terms of soil acidity, sedges are unfussy; they tolerate both acidic, neutral, and alkaline soil (pH between 5.5 and 7.5).

Temperature and Humidity

Sedges comprise one of the largest groups of plants with close to 2,000 species. They can be found in almost every part of the world, thriving in different climate conditions. Native sedges are generally hardy in zone 3 to 9 and non-native sedges in zone 6 to 9 but always read the plant tag to make sure the sedge you pick will fit your climate. If you live in an area with hot and muggy summers, select a native warm-season sedge that is tolerant of these conditions, such as catlin sedge (Carex texensis).

Fertilizer

Most sedges do not require any fertilization. At the maximum, feed them with a balanced slow-release fertilizer early in the spring, following to product label directions.

Pruning

Sedges should be cut back infrequently and only if they start to look ragged. Keep in mind that they don't grow nearly as fast as grasses, which makes up part of their appeal as a turf alternative.

Potting and Repotting Sedge

If you want to plant sedges in a container, select a compact variety. You can plant it in a container by itself or combine it with other plants that have similar watering and light requirements. Fill a container of at least 6 inches in diameter with a well-draining potting mix. Make sure it has large drainage holes. Unlike sedge planted in the landscape, container plants need frequent watering and monthly fertilizer during the growing season.

When the roots have filled the container, repot the sedge in a container at least 2 inches larger and with fresh potting mix.

Pests and Problems 

Sedges can be affected by different fungal diseases such as smut, rust, and leaf spot, and you might find aphids as well as fungus gnat larvae on them, the latter a sign that the soil is too wet. On the bright side, deer and herbivore critters leave the plant alone.

How to Propagate Sedge

While you can buy seeds, germination may be erratic so the easiest way to propagate sedges is by dividing the plants. In the early spring, dig up a dense clump, divide it into smaller sections, and replant them at the same depth in new locations.

Types of Sedge

'Bowles Golden' Tufted Sedge

Carex elata 'Bowles Golden' has slender, bright golden-green foliage. Plants form fountains of golden yellow that are 30 inches tall. Zones 5-8

'Fox Red' Curly Sedge

Carex buchananii 'Fox Red' has upright, arching bronze foliage that reaches 30 inches. Its unique foliage color is an attention-grabber. Zones 5-9

Golden Sedge

This selection of Carex elata lights up dark corners with its yellow-edged bright green leaves. It grows about 2 feet tall. Zones 5-9

Island Brocade Sedge

Carex ciliatomarginata 'Shima-nishiki' (sometimes also called Island Brocade Carex siderosticha), forms a dense groundcover with variegated leaves 6 to 9 inches long. Zones 5-8

Japanese Grass Sedge

This cultivar of Carex morrowii forms 18-inch-tall clumps with ½-inch-wide glistening green leaves. Zones 5-9

Variegated Japanese Grass Sedge

Carex morrowii 'Variegata' differs from the species in having a broad white stripe down the center of each leaf. Zones 5-9

Variegated Japanese Sedge

Carex oshimensis 'Evergold', sometimes called Carex hachijoensis, is a low-growing plant with creamy yellow variegation. It is hardy in Zones 6-9.

Sedge Companion Plants

Hosta

Hosta is among the easiest plants to grow, as long as you have some shade and ample rainfall. Hostas vary from tiny plants suitable for troughs or rock gardens to massive 4-foot clumps with heart-shaped leaves almost 2 feet long that can be puckered, wavy-edged, white or green variegated, blue-gray, chartreuse, emerald-edged—the variations are virtually endless. This tough, shade-loving perennial blooms with white or purplish lavender funnel-shape or flared flowers in summer. Some are intensely fragrant. Hostas are a favorite of slugs and deer.

Iris

Named for the Greek goddess of the rainbow, iris indeed comes in a rainbow of colors and in many heights. All have the classic, impossibly intricate flowers. The flowers are constructed with three upright "standard" petals and three drooping "fall" petals, which are often different colors. The falls may be "bearded" or not. Some cultivars bloom a second time in late summer. Some species prefer alkaline soil, while others prefer acidic soil.

Phlox

Just as diverse as the sedges, phlox comes in many different varieties so you can find one that fits well with your sedges. Phlox needs moist soil with excellent drainage that is slightly acid, neutral, or alkaline.