Stipa capillata Seeds | Needle Grass
LATIN NAME: Stipa capillata
COMMON NAME: Needle Grass
Plant Profile
Needle grass is a plant of the Eurasian steppe, and its whole strategy is packed into the seed. The clump is dense and upright, forty to eighty centimetres, with narrow, tightly rolled leaves that are grey-green in summer and straw in autumn. The panicles are narrow and contracted, and each spikelet ends in a long, bare awn, fifteen to twenty-five centimetres of it, which is the part that matters. In dry weather the awn is straight; when it rains or the air is damp, it twists, and as it dries it untwists, and the alternating movement walks the seed down into the soil, where the sharp callus anchors it. That mechanism is why the plant can colonise bare steppe and overgrazed ground, and why the same awns get into the wool, eyes and mouths of sheep. It is a grass of dry, calcareous, open ground from central Europe to Siberia and China.
Science & Biotechnology
The awn of Stipa capillata is a hygroscopic structure made of two bands of cells that swell differently as humidity changes, generating torque rather than simple bending. The result is a ratchet: the seed moves in one direction only, into the ground, and the backward-pointing hairs on the callus stop it coming out again. This is one of the classic examples used in teaching biomechanics of seed dispersal, alongside Erodium and Geranium. The species is a perennial bunchgrass with a deep fibrous root system and is one of the dominants of the dry Stipa steppes that run from Hungary to Mongolia, communities that are now fragmented by ploughing and overgrazing. It is a C3 grass, unlike the C4 grasses of the hot season, and it does most of its growth in spring before the soil dries.
Uses & Benefits
Its agricultural role is double-edged. On the steppe it is valuable spring grazing, and hay cut before the awns harden is decent fodder. Once the seed is ripe, though, the awns injure livestock: they work into fleece, into the skin between the toes and into the mouth, and in some years they cause real losses in sheep. It is also a useful species for stabilising dry, eroded slopes, since it establishes on poor ground and holds it with a dense root mass. In gardens it is grown in steppe and gravel plantings for the upright habit and the silvery awns, though it needs a dry summer to look right and flops in rich or humid conditions. The fibre has been used for brushes and rough cordage in eastern Europe, and the decoction of the whole plant has a minor folk record as a diuretic.
Growing from Seed
Sow in late winter or early spring, on the surface of a gritty, low-fertility mix, and press the seed in without covering it deeply, since it needs light. Cold stratification for four to six weeks improves the percentage, but fresh seed will often germinate without it at 18 to 22 degrees in two to four weeks. Keep the seedlings on the dry side and in full sun; damp compost at this stage is the usual cause of failure. Pot on individually, since the plants resent root disturbance once established. Plant out in autumn into poor, well-drained, preferably calcareous soil in the open, and do not add compost to the planting hole. Water only in the first summer. Leave the seed heads standing for winter interest, but cut them before they shed if you do not want seedlings.
Our Take
A steppe grass for poor, dry, sunny ground, with seed that drills itself into the soil. Keep it away from sheep, and do not feed it.
Related Reading
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