Most iris flowers bloom in the late spring or early summer, though some hybrid varieties are remontant and may bloom again in late summer. The Old Farmer's Almanac recommends planting irises in mid- to late summer.
Irises, named after the Greek goddess who rode rainbows, are unfussy, hearty flowers that come in over 300 varieties and are easy to grow. Iris flowers also attract hummingbirds and butterflies. The flowers grow to a height of approximately 28 inches and come in many different colors, including pink, orange, yellow, blue and purple. In order to thrive, an iris needs approximately six hours of sun per day and must be watered thoroughly and placed in an area with well-drained soil.