Iris sibirica aka Siberian Iris

Iris sibirica, or Siberian iris, belongs to the iris family. Its native range runs from central Europe to Mongolia. It grows in temperate regions, including damp woods, pastures and heaths. This herbaceous perennial grows from spreading rhizomes and forms clumps. It loses its leaves in winter and returns each year.

Garden plants reach about 2–4 feet [0.6–1.2 metres] tall. The RHS gives an upper height of 4.9 feet [1.5 metres]. Its listed spread reaches 1.6 feet [0.5 metres]. Narrow, blue-green leaves give the plant a grass-like look. The leaves turn brown or copper in autumn. Branched stems carry up to five violet-blue flowers in early summer. Each flower spans about 0.2 feet [0.06–0.07 metres]. Purple veins mark a white patch near each fall's base. The fruit forms a capsule, and the seed pods add interest.

Grow this iris in sun, with shelter from hot afternoon rays in southeastern gardens. Too much shade can reduce bloom and make stems lean. It accepts many soils, including clay, loam, sand and chalk. Acid, neutral and alkaline soils all suit it. Moist, fertile soil rich in organic matter gives good results. The soil should drain well rather than stay waterlogged. Young plants need steady moisture while their roots settle in. Established clumps can withstand some drought after one or two seasons. The RHS rates its cold hardiness as H7. Warm winters can reduce flowering, since a cold spell supports bloom.

Use it beside a stream or pond where soil stays moist. It also suits flower beds, informal gardens and courtyard plantings. Its flowers work well in cut arrangements. Divide crowded clumps when they begin to flower less. Seed and rhizome division both offer ways to raise more plants. Remove dead leaves in autumn and spent stems after flowering. Slugs, snails and thrips may attack it. Other risks include bacterial soft rot, grey mould and viruses carried by aphids.

Do not eat the rhizomes; they can cause stomach pain and vomiting. The plant can also harm pets that eat it. Sap may irritate skin, so wear gloves when handling it. One source reports starch extraction from roots, but questions its safety. This uncertain use does not make the raw roots safe food.