Japanese sedge

Japanese sedge: how do you recognise it?

Habit

Dense, arching clump about 30 cm tall and 40 cm wide.

Leaves

Narrow, stiff, leathery and glossy; green or with white to cream edges.

Flower

Small brownish spikes on short stems in April–May; they are barely noticeable.

Stem

Three-sided, as in most sedges.

Roots

A dense clump; some varieties form short runners.

Flowering: April–May · Plants: March–May and September–October · Pruning: March

Why grow it?

• Evergreen: fresh foliage all year, winter included.
• One of the few grass-like plants that really thrive in partial shade and shade.
• The white-edged leaves bring light to dark corners under trees and shrubs.
• Low maintenance: no cutting back, just remove a few dead leaves in spring.
• Also attractive in pots and troughs, even in winter.

Japanese sedge: where does it grow best?

• Partial shade or shade; avoid fierce afternoon sun, which scorches the leaves.
• Humus-rich sandy, loamy or clay soil, acid to chalky.
• Normally moist: do not let it dry out, but avoid soil where water stands.
• Plant 30–40 cm apart, in groups of three or more for the best effect.

Light

Partial shade and shade

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Normal

Size

0.3 m tall, 0.4 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Hosta: Large leaves next to the fine, white-edged clumps, in the same shade.
• Ferns: Finely cut fronds that contrast beautifully with the narrow, grass-like leaves.
• Christmas rose: Evergreen and flowering in winter: together they brighten a shady corner.
• Barrenwort: A tough ground cover for the same partial shade, with delicate spring flowers.
• Lungwort: Spotted leaves and blue or pink flowers in spring.

Japanese sedge: when and how to plant it?

Plant in March–May and September–October.

1. Plant in March–May or September–October, when the soil is not frozen or waterlogged.
2. Dig a hole twice as wide as the root ball and mix in some compost or leaf mould.
3. Set the clump at the same depth as in its pot, no deeper.
4. Plant 30–40 cm apart.
5. Water in well and keep the soil moist during the first year.
6. Spread a layer of leaf mould around the plants.

Care

Water

In the first year, water weekly in dry weather. After that, only in long dry spells; in a pot, regularly.

Feeding

Needs little: a layer of compost in March or April is enough.

Tidying

In March, comb dead leaves out of the clump with your fingers; wear gloves. Do not cut the clump back.

In a pot

Use good potting compost and a pot with a drainage hole. Repot or divide every two to three years.

Tip: Never cut Japanese sedge back like an ornamental grass: in March, just comb the dead leaves out of the clump. Plant white-edged varieties such as ‘Ice Dance’ and ‘Variegata’ in a dark corner, where they stand out most.

Japanese sedge: when to prune it?

Pruning months: March.

When: Do not cut back. In March, just remove dead and damaged leaves before new growth starts.

How:

• Comb through the clump with your fingers or a small rake to remove loose, dead leaves.
• Cut brown or damaged leaves off one by one at the base.
• Never cut the whole clump short: an evergreen sedge regrows only slowly afterwards.

Caution: Do not cut it to the ground like an ornamental grass: it is evergreen and recovers only slowly.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or September, lift the clump and split it with a spade or knife into pieces with roots and leaves. Replant at once and water.

Runners

With spreading varieties such as ‘Ice Dance’, you can detach a young rooted plant from the edge in spring.

Japanese sedge: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C: no protection is needed in Belgian winters.
• The leaves stay green all winter; in severe frost or cold wind the tips may turn a little brown.
• In a pot: place it in a sheltered spot against a wall and wrap the pot in hessian in hard frost. Water occasionally in dry winter weather.
• Lovely in winter troughs and pots by the front door, together with Christmas roses.

Diseases and pests

• Brown leaf tips: Caused by drought, fierce sun or cold wind. Water in dry spells, choose a sheltered, shady spot and trim off the brown tips in spring.
• Scorched leaves: Pale to brown patches on the leaves in full sun. Move it to partial shade or shade.
• Bare centre: Old clumps go bare in the middle. Lift them in spring, divide them and replant the young pieces from the edge.
• Root rot: On soil that stays wet in winter, the clump may rot. Make sure the soil drains well.

Through the year

• March: Comb out dead leaves. Add compost. Plant.
• April: Small brown flower spikes. Plant or divide.
• May: Still time to plant. Water in dry spells.
• June: Water in dry spells, especially young plants and pots.
• July: Water in dry spells.
• September: Plant or divide.
• October: Plant. A good time for winter containers.
• December: The evergreen leaves brighten the winter garden.

Did you know?

• Sedges are not true grasses. You can recognise them by their three-sided stems, hence the saying: sedges have edges.
• With some 2000 species, Carex is one of the largest plant genera. Belgium, too, has dozens of native sedges, often in wet places.
• The species name honours James Morrow, an American agriculturist who travelled to Japan with Commodore Perry’s expedition in 1853–1854 and collected plants there.