The leaves of the Japanese iris are dark green, sword-shaped and about 2 feet long. Japanese irises require moist, organic-rich, acid soils. However, many garden soils in Iowa are alkaline. Gardeners with alkaline soils should incorporate Canadian sphagnum peat into the soil before planting. Canadian sphagnum peat will lower the soil pH and also adds organic matter.
Japanese irises do well in partial shade to full sun.
They are excellent plants for moist soils near streams and ponds. Japanese irises, hardy in zones 4 to 9, don't have any serious pest problems. Plants can be left undisturbed for many years. Flowers are pale blue to violet with white or yellow crests on their falls. Plants bloom in mid-spring.