Astragalus onobrychis Seeds | Sainfoin Milkvetch
LATIN NAME: Astragalus onobrychis
COMMON NAME: Sainfoin Milkvetch
Plant Profile
Sainfoin milkvetch is a low, tufted perennial of twenty to forty centimetres with silvery pinnate leaves of many small leaflets and spikes of purple-pink pea flowers in early summer. It grows on dry grassland and on steppe from Austria to the Caucasus.
It is a member of the largest genus of flowering plants, with more than two thousand five hundred species, most of them in the dry mountains of Central Asia. This one is a plant of the European steppe, and it is grown in rock gardens and in wildflower meadows for its early flower. The leaflets are silvery beneath and the whole plant has a soft grey look, even in full flower.
Science & Biotechnology
The genus is famous among plant chemists for selenium accumulation: a few species take up selenium from the soil and store it in their tissues at concentrations that kill livestock, and the poisoning of range cattle in the American west was traced to them. This species is not one of the accumulators, but the genus as a whole needs care when it is grazed.
The plant fixes nitrogen through rhizobia, and its deep taproot allows it to survive a summer drought that kills shallow-rooted legumes. The seed coat is hard and a proportion of every batch stays dormant for years, which is why a stand can reappear after a gap of cultivation.
Uses & Benefits
The plant is grown in rock gardens, in gravel beds and in meadow plantings, where its silver foliage and its early flower are the attraction. It is also used in a wildflower mix for poor, dry soil, and it is one of the few legumes that will grow in a thin calcareous turf.
In the steppe it is grazed by sheep and cut for hay, though it is not sown as a crop in the way that sainfoin or lucerne are. It has no medicinal use in modern practice, and it is not sold as a herb. The dried flowers are also used in a folk tea in the Balkans, though the genus is not one to experiment with given its relatives.
Growing from Seed
Scarify the seed lightly, since the coat is hard, and sow in spring at fifteen to eighteen degrees. Germination is slow and uneven, and the seedlings should be pricked out before the taproot reaches the bottom of the tray.
Plant out in full sun on poor, sharply drained soil, and do not enrich the ground, which produces soft growth and few flowers. The plant resents transplanting once established, so choose the site carefully. Cut the flower spikes after they fade if seed is not wanted, and leave the foliage to die back naturally. In a wet winter the crown rots, so plant it on a slope or in a raised bed of grit and limestone.
Our Take
A silver-leaved steppe legume for a gravel bed or a wild meadow, and one that asks for poor soil and no kindness. Grow it dry.
Related Reading
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