Cultivars
'Alba'
This rhizomatous perennial produces white flowers.

'Exception'
This rhizomatous perennial produces deep purple flowers with large falls.

'Jodlesong'
This has upright long linear, dark green leaves and forms a dense clump up to 1.2 m (4 ft) tall. It produces deep purple flowers that are marked in bright yellow at the base of the petals.

'Mystic'
This rhizomatous perennial produces purple-blue flowers that have red margins.

'Peter Blue'
This rhizomatous perennial produces mid blue flowers.

'Moonlight Waves'
This rhizomatous perennial produces white flowers with lime green centres.

'Tsuyu-No-Gyokusho'