Iris ensata Yezo-nishiki - Japanese Water Iris

They like a damp and marshy soil, without limestone. They also accept a fresh soil, even if it is not waterlogged, provided it does not dry out in summer. On the other hand, they prefer a rather dry soil in winter. At Le Clos, we have planted them near an artificial stream, with the water level kept high during the summer. In winter, we let the level drop by about 15cm (6in), so that the stumps are above the water, as in nature where the level of rivers drops in winter and rises again in spring with the melting snow. Their cold resistance is excellent up to about -12°C (10.4°F). It is further increased if the soil is dry.