Iris ensata Carnival Prince - Japanese Water Iris

They like damp and marshy soil, without limestone. They also tolerate a cool soil, even if it is not waterlogged, as long as it does not dry out in summer. On the other hand, they prefer a rather dry soil in winter. We have planted them near an artificial stream, the water level of which is 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 decreases in winter and rises in spring with the melting of snow. Their cold resistance is excellent up to about -18°C (-0.4°F). It is even increased if the soil is dry.