Soft rush

How to recognise it

Habit

Dense, upright clump of 40–100 cm, with dozens to hundreds of stems.

Stem

Round, smooth and glossy bright green, very finely lined; filled with continuous white pith. Soft and flexible.

Leaf

No true leaves: only brown, glossy sheaths at the base of the stems.

Flower

Loose or sometimes compact cluster of small brownish-green flowers with six tepals, apparently on the side of the stem, from June to August.

Fruit/Seed

Small egg-shaped capsules full of tiny seeds that become sticky in wet weather and so travel on animals and shoes.

Confusion with

Hard rush is blue-green and dull, with strongly ridged stems and interrupted pith, in compartments. Compact rush has a dense, ball-shaped flower cluster and a ridged stem, especially just below the flowers.

Flowering: June–August · Pruning: March

Why grow it?

• Stays largely green in winter and gives structure to a wet corner or pond edge.
• Insects and spiders overwinter in the dense clumps, and in wet pastures birds such as snipe use them for cover.
• Tough and easy: grows on wet, poor or compacted soil where little else will grow.
• Ideal for a swale or rain garden: it tolerates both wet feet and short dry spells.
• Once used for weaving mats and baskets, and its pith served as a wick.

Soft rush: where does it grow best?

• In the wild: wet and damp pastures, ditch banks, drainage channels, wet heath, clearings and paths in damp woodland.
• Sun to partial shade.
• Wet to moist, preferably somewhat acid soil; tolerates compacted clay and temporary standing water.
• In the garden: a pond edge in up to 10 cm of water, a swale, a wet ditch or a bog bed.

Goes well with

• Ragged robin: Pink, ragged flowers in May–June in the same wet soil.
• Meadowsweet: Creamy, fragrant plumes in summer.
• Marsh thistle: Purple thistle flowers for butterflies and bees.
• Yellow iris: Yellow flowers at the pond edge next to the green clumps.
• Water mint: Low, fragrant ground cover on wet soil.

Soft rush: when and how to plant it?

1. Buy soft rush from a nursery for aquatic or native plants; never dig up clumps from the wild.
2. Plant from April to September in wet soil or in shallow water up to 10 cm deep.
3. Space plants 40–50 cm apart as individual clumps, or use 3–5 per m² for dense cover.
4. You can also sow: in spring, scatter the fine seed on wet, bare soil and press it in without covering it, because it germinates in the light.
5. Keep the soil really wet in the first year, including summer.

Care

Watering

Never let it dry out; it will survive a dry summer, but turns brown.

Feeding

Not needed: it actually does well on poor soil.

Tidying

In March, pull the dead brown stems out of the clump or cut the clump back.

Seedlings

It self-seeds on wet, bare soil. Pull out unwanted seedlings while they are young.

Rejuvenating

Old clumps go bare in the middle: divide them every 3–4 years.

Tip: Put soft rush in a swale or a low spot in the garden where rainwater collects: it tolerates both wet feet and short dry spells, and its clumps hold the soil together.

Pruning and mowing

Pruning months: March.

When: In March, before the new stems appear.

How:

• Cut the clump back to 5–10 cm above the ground, or just pull out the dead stems.
• Leave the clumps standing all winter: insects and spiders overwinter in them.
• Use sharp secateurs or shears: the tough stems bend rather than snap.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In April–May, split a clump into pieces with a spade and replant them straight away in wet soil. Quick and reliable.

Seed

Ripe in August–September. Sow in spring on wet soil without covering: the fine seed germinates in the light.

Soft rush: how does it get through the winter?

Hardy to −30 °C.

• The stems stay largely green; only the oldest turn brown.
• Fully hardy, to about −30 °C.
• The dense clumps shelter overwintering insects, spiders and small creatures.
• The seed remains viable in the soil for decades.

Diseases and pests

• Self-seeding: On wet, bare soil it can seed itself heavily and take over a meadow. Pull up seedlings and keep the turf closed.
• Bare clumps: Old clumps die out in the middle. Divide them and replant the young pieces from the edge.
• Brown stems: A sign of drought or of a clump full of dead stems. Water, and tidy up in March.
• Cuckoo spit: Froth on the stems in May–June comes from froghopper larvae. Harmless, leave them alone.

Through the year

• March: Remove dead stems or cut the clump back.
• April: Plant, divide or sow on wet soil.
• May: New stems grow. Leave the cuckoo spit alone.
• June: Flowering starts: brownish-green clusters on the stems.
• July: Flowering. Keep the soil wet in dry weather.
• August: Seed ripens. Pull up unwanted seedlings.
• September: Still time to plant. Collect seed.
• November: Leave clumps standing as winter shelter.
• December: Largely green through the winter.

Did you know?

• The white pith was once dried, dipped in fat and burned as a simple rushlight, or used as a wick in oil lamps.
• In Japan, a cultivated form of this rush is used to weave the top layer of tatami mats.
• The seed can survive in the soil for decades and germinates as soon as light reaches wet, bare soil, for example after a pond has been dug.