It performs best in sun or partial shade in a rich, moist, acid soil. Do not use lime or other pH raising materials around Japanese Iris. Cut the plants back to a height of 6 inches in the fall. Japanese Iris are useful near water and can be divided every 3-4 years as plants become crowded. Replant the rhizomes about 2 inches deep and 18 inches apart. This Iris is happy in shallow standing water and cannot tolerate hot, dry conditions. Cold hardy to 10-15° F.

Iris ensata is grows in the wet land throughout the Japanese archipelago. The genus Iris gets its name from the Greek goddess Iris, who was goddess of the rainbow. In Greek mythology, Hera, who was Queen of Olympia, was impressed by Iris' purity and honored her with a flower that bloomed with all of the colors in her robe. The specific epithet is from the Latin word 'ensatus' meaning "sword" in reference to the shape of the leaves. We grew this plant when we were growing many other aquatic plants from 2004 until 2012 as part of our Aquatic Plants Program. 

The information displayed on this page about Iris ensata 'Blue' is based on our research conducted about this plant from books in our nursery library as well as from information that is provided by reliable online resources. We also have included our own observations made about it as it grew in the nursery gardens and other gardens visited, as well how the crops of this plant performed in the containers when we had them in our nursery field. We also include comments received from others and welcome hearing from anyone who has information about this plant, particularly if it includes cultural information aiding others to better grow it.