Blue/Purple Water Iris

Blue/Purple Water Iris, is a water iris. It grows from the water's surface to about three or four inches deep, with horizontal rhizomes absorbing high nutrient levels from the soil and water. It can be planted at the edge of an earth pond or in a wide pot near the surface of a lined pond in loam soil (like what you find beneath grass). 

Fertilize before and after blooming in spring. Divide more than a month after flowering until about 8 weeks before frost never in spring.