Iris tectorum has wide, lilac-blue to purple flowers with white crests and dark veins in early midsummer. Its dense fans of broad, ribbed, glossy green, sword-like leaves are 12″ long. The foliage may become a bit floppy with age. A perennial, Iris tectorum spreads rapidly to form a medium-height ground cover.

Also known as Japanese Roof Iris, Iris tectorum prefers part sun to sun with some afternoon protection and moist to average, well-drained soil. It is drought tolerant, once established, but maintains its best appearance with consistent moisture. Japanese Roof Iris responds well to fertilization during the growing season.