Japanese sedge—also known as Morrow's sedge or evergold carex—is a semi-deciduous rhizomatous evergreen native to Central and Southern Japan. It forms a densely tufted tussock of slender foliage that shimmers in the breeze, with flat, dark green leaves that are 12 inches long and 1/4- to 1/2-inch wide.
Best planted in spring or fall, the growth habit of Japanese sedge is dense, clumping, and mounding. The plant will grow at a moderate pace, reaching its mature height and spread within about two years' time. Flowering spikes emerge on the plant in mid-to-late spring, with each flower comprised of four to five petals.
|Common Name||Japanese sedge, evergold carex, Kan suge, Morrow's sedge|
|Botanical Name||Carex morrowii|
|Mature Size||12–18 in. tall, 18–24 in. wide|
|Sun Exposure||Partial shade, full shade|
|Soil Type||Moist but well-drained|
|Soil pH||Neutral to acidic|
|Bloom Time||Spring, summer|
|Hardiness Zones||5–9 (USDA)|
Japanese Sedge Care
Japanese sedge is a very versatile plant—it mingles attractively with flowering bulbs and perennials and is a great way to create texture in your landscape. It can be used in garden beds or as a border plant and is excellent for growing around ponds or water gardens due to its love of moist soil. In addition to growing well in containers, it also looks good in rock and cottage gardens, and it will thrive in shadier spots, like beneath trees and shrubs.
Mass plantings of Japanese sedge will attract a slew of pollinators to your yard, including butterflies and bees. Similar to tussock and foothill sedges, Japanese sedge is deer tolerant and low-maintenance, offering year-round interest, and can even thrive through the winter as long as it doesn't get too cold. Additionally, issues with pests or diseases are fairly rare.
Japanese sedge plants are unique in that they thrive in shady areas, like under a canopy of trees or in spots shaded by your house or other structure. They can also do well with a little dappled sunlight, though it should be minimal (no more than four to five hours of partial sunlight a day). If exposed to too much sun, the plant's foliage will bleach and its green color will fade significantly.
Plant your Japanese sedge in any soil blend that is moderately moist, fertile, and well-draining. The plant adapts well to a variety of different soil types (like chalk, clay, loam, or sand) and pH levels but is not keen on dry soil.
Japanese sedge plants should be watered consistently, especially as they're getting established in your landscape. A good rule of thumb is to drench the plant when the top layer of soil has dried out, and you should never let the ground dry out entirely if you can help it. Once the plant is established in your landscape, it will be moderately drought-tolerant. When watering Japanese sedge plants, aim your hose or watering can at the base of the plant instead of into the dense foliage—this will help reduce the risk of fungal diseases.
Temperature and Humidity
Japanese sedge plants are cool-weather lovers and experience their most significant growth when temperatures are below 75 degrees Fahrenheit. That said, they tolerate a wide range of temperatures and have no special humidity requirements. To protect the plant during especially cold winters, you can cover it with a thick layer of organic mulch around the root zone.
You do not need to worry about fertilizing your Japanese sedge plants—they establish themselves quite easily and will grow just fine without the help of additional nutrients.
Types of Japanese Sedge
More than 1500 species of Carex grow in moist-to-wet areas around the world, making it challenging to identify individual species. There are a variety of common grass types in the Carex genus that are sometimes confused with Japanese sedge, including foothill sedge and tussock sedge. However, there are a number of well-known varietals of Japanese sedge as well, many of which differ only slightly in color or appearance but not care. They include:
- Carex morrowii 'Variegata': This varietal looks largely the same as Japanese sedge, but boasts leaves that have bright white margins on either side.
- Carex oshimensis 'Evergold': This varietal is characterized by creamy yellow leaves that have bright green margins. It grows in a low, grass-like mounded clump similar to Japanese sedge.
- Carex morrowii 'Silk Tassel': Perhaps the most unique of the bunch, this varietal has leaves that are thin, whispy, and green-silver in color. The fine texture of the leaves lends the plant a fountain or mop-like effect.
Pruning Japanese Sedge
It's not necessary to prune your Japanese sedge throughout its growing season. Shaping the plant is also unnecessary, as long as you like its free form and it's not infringing on any nearby plants. However, if you do not live in an area that promotes its health all year long, Japanese sedge can (and should) be cut down before winter so it's ready to welcome fresh foliage the following spring.
To prepare it properly, trim back the leaves to ground level, being careful not to prune too aggressively and rip out the plant's roots. Remove any debris from the area around the plant and mulch over the trimmed foliage if desired.
Propagating Japanese Sedge
Division is the recommended means of propagation for Japanese sedge. Plan to divide your plant every three to four years, which is around the time that the center of your mature plants will see a reduction in the number of new leaves they produce. Divide the plant in the spring, gently breaking apart clumps of rhizomes and planting each one separately.
How to Grow Japanese Sedge From Seed
Sow sedge seeds in a good seed-starter mix and keep the containers in a warm area with dappled light. Add water whenever the topsoil feels dry. The seeds should establish roots in a few months and when they've done so, it is safe to plant them outdoors, a project that is best done in the spring or fall.
If you live in an area that experiences mild winters, there is no need to take special precautions with your sedges when the seasons change. You may want to put a thick layer of organic mulch around the base of the plants before the temperatures drop and suspend your watering schedule in the late fall and through the winter.
However, if your winters deliver chilly temperatures and freezes are a normal occurrence, then it is probably best to cut your sedges to the ground, mulch around the base of the plants, and wait for them to grow again in the spring.
How fast does sedge grow?
Given the right environment, Japanese sedge grass should reach its maximum size in about two years.
Does Japanese sedge self-seed?
Yes. The plant will drop its seeds regularly, helping it to fill your garden with its striking foliage. Because the plant is relatively slow growing, invasiveness tends not to be a problem, as you can simply dig up new growth if you don't want more grasses.
How long does Japanese sedge live?
Given the right care and planted in the right location, Japanese sedge grasses can live about 10 years.