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Carex morrowii

Japanese sedge

Cyperaceae Japan

Deer Resistant Container Friendly

SunPart Shade – Full Shade

WaterMedium

HardinessZones 5–9

Overview

Carex morrowii is an evergreen sedge in the Cyperaceae forming dense tufted clumps 12–18 inches (30–45 cm) tall and 12–24 inches (30–60 cm) across. Leaves are stiff and arching, 8–16 inches (20–40 cm) long and 0.25–0.5 inch (6–12 mm) wide, glossy dark green above with a keeled midrib and minutely toothed margins that abrade skin drawn along them. Clumps expand slowly from short rhizomes, adding 2–4 inches (5–10 cm) in diameter a year, while selections such as C. morrowii 'Ice Dance' run more widely. Flowering culms are triangular in cross-section, rise 12–20 inches (30–50 cm), and carry a terminal male spike above 2–4 lateral female spikes, all green-brown and 0.5–1.5 inches (13–38 mm) long. Foliage holds green through winter in zones 7 and warmer, but in zones 5 and 6 the blades bleach, tatter, and shred by February and are removed before new growth. Leaf tips brown and growth slows where plants sit in full afternoon sun or in soil that dries below field capacity for more than a week.

Native Range

Carex morrowii is native to Japan, occurring on Honshu, Shikoku, and Kyushu in the understorey of broadleaf and mixed woodland and on shaded rocky slopes. It grows from near sea level to about 3,300 feet (1,000 m), often on humus-rich soil over rock. Populations also occur in coastal woodland where salt-laden wind is filtered by the canopy.

Suggested Uses

Planted as evergreen edging and groundcover in shaded borders, spaced 12–18 inches (30–45 cm) apart for continuous cover within two seasons. Also grown in containers of 2 gallons (7.5 L) or larger and in shaded courtyard plantings, where the arching form persists through winter. Massed beneath deciduous trees the clumps persist under root competition, though supplementary water is needed through the first two years.

How to Identify

Flowering stems are triangular in cross-section, separating sedges from the rounded stems of true grasses. Leaf blades are 0.25–0.5 inch (6–12 mm) wide, stiff, glossy on the upper surface, and carry minutely toothed margins that feel abrasive when drawn between the fingers. Each culm holds one narrow male spike at the tip above 2–4 shorter female spikes spaced along the upper stem. Clumps stay green through winter, unlike the deciduous Carex spp. species that die back to the crown in autumn.

Appearance

Size & Dimensions

Height1' - 1'6"

Width/Spread1' - 2'

Reaches mature size in approximately 3 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~3 weeks

Spring

Flower spikes appear in April and May, standing 12–20 inches (30–50 cm) on triangular culms held just above or within the foliage. The terminal spike is male and 0.8–1.5 inches (20–38 mm) long, with 2–4 female spikes below it, all green-brown and without petals. Pollination is by wind, and the spikes persist 3–4 weeks before the culms brown and bend. Seed set is light in cultivation and self-sown seedlings are uncommon in garden conditions.

Detailed Descriptions

Foliage Description

Glossy dark green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 2-6 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.0(Neutral)

357912

Soil Types

loam clay silt

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2-3 years to mature clump size

Care & Maintenance

Care Guide

Two to six hours of direct sun daily, with shade through the afternoon, keeps the blades dark green; more than about six hours in zones 7–9 scorches the leaf tips. Evenly moist, free-draining soil with a pH of 5.5 to 7.0 supports steady growth, and clumps in dry soil thin from the centre outward. Watering to keep the root zone damp during dry spells longer than 10 days sustains the foliage. The plant is hardy in USDA zones 5–9 and survives winter lows near -20°F (-29°C), though blades above the crown are killed at around 5°F (-15°C). A single spring application of balanced fertiliser at 1 pound per 100 square feet (0.5 kg per 9 m²) covers the season. Crown rot follows planting in soil that stays saturated, and slugs graze new blades in wet springs.

Pruning

Cutting the clump back to 3–4 inches (7.5–10 cm) in late February or early March removes winter-damaged blades before new leaves emerge. Where foliage stays intact through winter, running gloved hands through the clump strips dead blades without shearing living ones. Cuts made after new growth has started leave blunt brown tips on the new leaves for the rest of the season. Division every 3–4 years in early spring restores clumps that have opened at the centre.

Pruning Schedule

early spring