Blue Flag Iris blooms in May and June with beautiful blue-violet flowers that have yellow throats. The flower petals and sepals provide a bee-sized landing strip and the markings are like runway signs guiding numerous pollinators to the plant. Iris versicolor is visited by numerous bumblebees, mason bees, sweat bees digger bees and by syrphid flies. Although it will grow happily in regular gardens, it is indispensable for bog gardens, wet meadows and streamsides. Iris versicolor's nutrient filtering ability makes it particularly useful in retention basins and bioswales restoration projects because of its ability to decontaminate the soil by absorbing and storing harmful pollutants. Blue Flag Iris is a good native alternative to the invasive Yellow Flag Iris (I. pseudacorus).