The flowers often have veins, stripes, or blotches of a contrasting color. Japanese iris requires moist, acid soils. It grows in partial to full sun. Compared to bearded iris, Japanese iris has few insect or disease problems. The light yellow flowers have brown blotches on their falls.
Yellow flag is an excellent plant for wet areas along streams and ponds.
It performs best in moist to wet soils in partial shade to full sun. Plants may grow 3 to 4 feet tall when provided ideal growing conditions. In spring, the newly emerged leaves of 'Variegata' have yellow stripes. The variegation gradually disappears by mid-summer. It is a tall, warm-season, perennial grass which is usually found in wet prairies.