Soft rush: identification, planting, care and price

Soft rush (Juncus effusus) is a native rush, not a grass. It forms dense tufts of smooth, glossy green stems 20 centimetres to 1 metre tall. Small brown flowers appear on the side of the stems in summer. Plant soft rush in wet, acid soil, at the edge of a pond or in a waterlogged corner.

Soft rush at a glance

Leaf

all year

Flower

June to August

Fruit

August to January

JanFebMarAprMayJunJulAugSepOctNovDec

How do you recognise soft rush?

Look at the stems first. They are round, smooth and a glossy bright green. Pinch one open and you find white, spongy pith that runs through without a break. Soft rush usually has no leaf blade. At the base there are only red-brown to black-brown sheaths, small tubes wrapped around the stem.

The flowers are small, with six brown petals and usually three stamens. They sit in a loose cluster that seems to grow out of the side of the stem. The green part above it is a bract that carries on exactly like the stem. Small seed capsules follow the flowers, glossy brown to greenish.

Two plants look like it. Compact rush (Juncus conglomeratus) has grooved, dull blue-green stems, and you can feel the grooves with a fingernail. Its flowers sit in a tight little knob. Garden centres also sell corkscrew rush, a cultivated form with stems that twist like a corkscrew. Wild soft rush has straight stems.

Where does soft rush grow best?

Soft rush grows in full sun and in partial shade. Partial shade means three to six hours of direct sun a day around midsummer. The soil must stay moist at all times, preferably acid and fairly heavy, such as clay or loam. In the wild, soft rush grows along ditches, in marshes, in wet meadows and beside woodland paths. It also comes up in gardens and between paving stones.

Soft rush struggles in these places:

• A border that dries out in summer. The roots need to stay wet all the time, and a dry border does not hold on to that moisture.
• The deep middle of a pond. This rush belongs on the shallow edge, not in deep water.

Soft rush stays green through winter. In January a clump is still a green tuft at the water's edge.

The app puts your own plot on a plan to scale, with the buildings around it. On that plan you measure for yourself whether the pond edge has room for a clump a metre wide.

Planting and caring for soft rush

Nurseries sell soft rush as a young plant in a small pot, sometimes in a pond basket. Take off the nursery pot and plant the root ball as it is. Put it on the edge of the pond, with at most 10 centimetres of water above the roots, or in wet ground right beside it.

For separate clumps, leave half a metre to a metre between plants. That is how wide a full-grown clump gets. On planting day the gaps look bare, but the space fills in on its own. For a dense bank, nurseries plant nine per square metre. Keep the soil from drying out in the first summer.

Many bird species breed from March through July. Before you work on a clump in those months, check for a nest between the stems.

What goes wrong with soft rush?

The stems turn brown and limp. The soil has become too dry. Water thoroughly, or move the plant closer to the water.

Young soft rush plants come up everywhere. The plant seeds itself. Its seed travels on the wind, or sticks to animals like a burr. Pull out the seedlings young wherever you do not want them.

In winter part of the clump turns the colour of straw. Those are old stems. Cut them away in spring, and the green heart stays.

You see hardly any flowers. The flowers are small and inconspicuous. That is normal for soft rush, and nothing needs doing.

There are spots or small creatures on it. Soft rush rarely suffers from pests or diseases. Usually you can leave it alone.

Which insects and birds use soft rush?

The caterpillar of the red sword-grass (Xylena vetusta), a moth, feeds on soft rush among other plants. Its other food plants include bog myrtle, yellow iris and heather. This moth is rare in the Netherlands and only turns up now and then. The provisional Dutch Red List classes it as critically endangered. Which birds and other insects use soft rush is not well described for this species.

Is soft rush poisonous or edible?

Soft rush is not known to be poisonous. That does not mean the plant is edible.