Corkscrew rush

Sun

Full sun to partial shade; strongest growth usually occurs in full sun where moisture is plentiful.

Water

High; keep the root zone constantly moist or wet. Established plants tolerate shallow standing water.

Soil

Moisture-retentive loam or clay, preferably acidic to neutral; tolerates poorly drained soil.

Height

1-2 ft (0.3-0.6 m)

Spread

1-2 ft (0.3-0.6 m)

Flowers

Summer; small, inconspicuous greenish-brown flower clusters appear near the stem tips.

Foliage

Evergreen. Smooth, cylindrical green stems twist into spirals and loops; the true leaves are reduced to small basal sheaths.

Growth

Moderate; faster in warm weather with constant moisture.

Care needed

Low

• Deer resistant
• Cold hardy
• Heat tolerant
• Wildlife

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   1.2 ft (0.36 m)

3. After 2 years

   1.4 ft (0.42 m)

4. After 3 years

   1.5 ft (0.45 m)

   full size

About 2 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Native to

the US, Canada and the UK

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Fast

• Keep the soil wet throughout active growth; do not let container compost dry out.
• For pond planting, position the crown at water level or no more than 2 in (0.05 m) below it.
• Feed container plants lightly in spring; plants in fertile garden soil usually need no extra fertilizer.
• Divide congested clumps in spring, retaining healthy roots and several growing points in each division.
• Remove any straight-growing shoots at their base to preserve the curled appearance.
• In cold regions, sink pots into the ground or protect their root balls from prolonged freezing.

Pruning. In late winter or early spring, cut brown or damaged stems close to the base before new growth starts. Leave healthy green stems intact unless the whole clump needs renovation.

Late winter

Remove dead stems and check that container roots have not dried out.

Spring

Plant or divide clumps as growth resumes, keeping divisions wet while they establish.

Late spring

Give container plants a light feed and check that pond baskets sit in shallow water.

Summer

Check containers frequently and top up water during hot or windy weather.

Early autumn

Remove unwanted seedlings and straight-growing shoots.

Late autumn

Protect exposed containers in cold climates; leave healthy stems for winter structure.

• Use a single clump in a simple, watertight container where the curled stems can be seen close up.
• Plant along shallow pond margins with Japanese iris for contrasting upright and curled shapes.
• Repeat small groups through a bog garden to give continuity among broad-leaved plants.
• Combine with ferns and moisture-loving sedges in a damp courtyard with partial shade.

Garden styles it suits: Bog garden, Architectural minimal, Contemporary minimal, Modern courtyard, Japanese and Small-space.

Plant it with: Japanese iris, Marsh marigold, Astilbe and Royal fern.

Wildlife: Dense stems provide shelter for small invertebrates around water. Flowers are wind-pollinated and offer little nectar value.

• Brown, brittle stems often indicate drying out: restore constant moisture and remove dead growth.
• Weak, sparse growth can result from deep shade: move to a brighter position while keeping the roots wet.
• Straight shoots can outgrow the curled stems: remove them at their point of origin, dividing the clump if necessary.
• Winter damage is more likely in exposed pots: insulate the container or sink it into the ground before severe frost.

Not known to be toxic to cats, dogs, horses or people. No particular part is established as poisonous, but information specific to this cultivar is limited; it is not an edible plant.

Where it spreads. The species, Juncus effusus, can spread strongly in wet ground and is a troublesome introduced weed of wet pasture in New Zealand. 'Spiralis' is generally more restrained, but can expand by short rhizomes and produce seedlings that may have straight stems; contain it where spread would be a problem.

• Soft rush (Juncus effusus)

  The ordinary species has predominantly straight, upright stems rather than tight curls.

• Corkscrew rush 'Big Twister' (Juncus effusus 'Big Twister')

  Usually has thicker stems and larger, more open coils; young plants can be difficult to distinguish without a reliable label.

• Corkscrew albuca (Albuca spiralis)

  Has curled leaves arising from a bulb and produces yellow-green flowers; unlike corkscrew rush, it needs freely draining soil and a dry resting period.

The Latin effusus means spreading or loosely arranged, referring to the flower clusters, while 'Spiralis' describes the spiralling stems.

Propagation. Divide in spring to retain the curled stems. Seed-grown plants are variable and may not resemble the parent cultivar.

Accepted botanical name

Juncus effusus

In the US and Canada

Native in Alaska, Canada, the lower 48 states and St. Pierre and Miquelon. Introduced in Hawaii.

Native range

Afghanistan, Alabama, Alaska, Albania, Algeria, Altay, Arizona, Arkansas, Austria, Azores, Baleares and Baltic States.

Measured

Soil pH 5.5 to 8.8. Average height 66 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.