These are hardy, damp-loving irises, widespread in the Northern Hemisphere. They make spreading mats of rhizomes, and flower best if planted in sunny places, so long as the dampness, or even wetness, is ensured. They include our British native flag iris.

Iris versicolor is a species from north-east America, keeping its foliage throughout the winter. It has clusters of a few violet flowers with darker veins and a downy, yellow spot on the falls.