Juncus rigidus Seeds | Spiky Rush

Spiky rush with stiff leafless pointed stems standing in shallow marsh water — Spiky Rush (*Juncus rigidus*): Juncaceae, the salt-tolerant marsh rush of North Africa and the Middle East.

LATIN NAME: Juncus rigidus

COMMON NAME: Spiky Rush

Plant Profile

Spiky rush is a plant of salt flats and brackish marsh, and it is built to look uncomfortable. It grows fifty centimetres to a metre and a half, in dense, dark clumps of stiff, cylindrical, leafless stems that end in a sharp point, with the true leaves reduced to sheaths at the base. The inflorescence appears to come out of the side of the stem rather than the top, because the bract above it continues the line of the stem and looks like a continuation of it.

The whole plant is grey-green and rigid, and the clumps stand upright through wind and flood. It is native to the Mediterranean, North Africa, the Middle East and parts of India, where it grows in saline wetlands, around salt pans and along the margins of brackish water. It tolerates salt concentrations that would kill most rushes, which is why it is one of the few plants that will grow on a salt flat.

Science & Biotechnology

The species is a halophyte, and its tolerance comes from the usual suite of adaptations: it excludes some salt at the root, sequesters what gets through in vacuoles, and sheds the excess in old tissue. That makes it useful in studies of saline agriculture and of phytoremediation, and it has been tested for the rehabilitation of salt-affected land. It is also a species of brackish wetlands that are under pressure from drainage and development, so its ecology is documented more in the context of habitat loss than of crop improvement.

The genus Juncus is distinguished from the sedges by having round stems rather than triangular ones, and by flowers with six tepals rather than scales. Spiky rush is one of the larger and more robust members of the genus, and its rigid stems and sharp points are a defence against grazing as well as a consequence of growing in exposed, windy places.

Uses & Benefits

The stems have been used for mats, baskets and coarse matting in North Africa and the Middle East, where the plant grows in sufficient quantity to be harvested, and the pith was used for lamp wicks in the way that other rushes were. It should be said clearly that the classical Chinese drug Deng Xin Cao, the pith of the rush used as a wick and as a calming herb, comes from Juncus effusus and not from this species, and the two should not be substituted.

In the garden it is a plant for a saline or brackish spot, a wildlife pond margin, or a coastal garden where other marginals fail, and its stiff, architectural clumps look well against water and gravel. It is also useful in a reed bed or a constructed wetland treating saline water. It spreads slowly by rhizome and is not invasive in the way of the soft rushes.

Growing from Seed

The seed is very small and should be surface-sown onto wet compost, pressed in but not covered, and kept standing in water at about twenty degrees. Light and constant moisture are both required, and germination is usually within three to five weeks.

Prick the seedlings out into small pots of wet loam and grow them on with the pots standing in two centimetres of water. Plant out at the water’s edge, in full sun, in soil that stays wet; the plant tolerates brackish water and occasional inundation with sea water. Cut the old stems back in early spring before the new ones emerge, and divide clumps every few years to keep them open.

Our Take

A salt-marsh rush for wet, brackish ground, with useful stems and a clear identity worth respecting. Tidal margins and salt flats suit it better than a tidy border.

Herb Seeds