It is hardy in zones 3 to 9. Because of its small size, crested iris can be grown in front of the perennial bed or border. It also can be naturalized in the woodland garden. Plants bloom in late spring. The flowers are yellow with brown blotches on their falls.
Yellow flag performs best in moist to wet soils in partial shade to full sun.
It is an excellent plant for wet areas along streams and ponds. In spring, the newly emerged leaves of 'Variegata' have yellow stripes. However, this variegation disappears by mid-summer. Yellow flag is hardy in zones 4 to 9. The flowers appear in late spring.