Iris tectorum Japanese Roof Iris
A very beautiful, evergreen species that is native to forest margins, sunny banks, meadows and damp places in Burma, China and Japan (where it has historically been planted on thatched roofs). Produces low fans of clump-forming, broad leaves and beautifully patterned, violet-blue flowers in summer. Height 60 cm. Sun to part shade in a moist but well-drained soil.