Cultivars
'Allenii'
This rhizomatous perennial has divided dark green foliage and forms a clump. From mid to late spring produces large pale lavender-blue flowers that are suffused in purple on the outside up to 40 mm (1? in) wide. It is suitable for coastal and inland regions and grows in USDA zones 5-9.

'Flore Pleno'
This rhizomatous perennial has divided dark green foliage and forms a clump. From mid to late spring produces small double white flowers up to 30 mm (1? in) wide. It is suitable for coastal and inland regions and grows in USDA zones 5-9.

'Latvian Pink'
This rhizomatous perennial has divided dark green foliage and forms a clump. From mid to late spring produces large single pale rose flowers that deepen in colour as they mature. It is suitable for coastal and inland regions and grows in USDA zones 5-9.

'Maret'
This rhizomatous perennial has divided dark green foliage and forms a clump. From mid to late spring produces double white flowers and with apples that are suffused in green. It is suitable for coastal and inland regions and grows in USDA zones 5-9.

'Pleaniflora'
This rhizomatous perennial has divided dark green foliage and forms a clump. From mid to late spring produces small double flowers with white inner tepals that are tipped in green and the outer tepals are green. It is suitable for coastal and inland regions and grows in USDA zones 5-9.

'Robinsoniana'
This rhizomatous perennial has divided dark green foliage and forms a clump. From mid to late spring produces large pale lavender-blue flowers up to 40 mm (1? in) wide and is accompanied by creamy-grey bracts. It is suitable for coastal and inland regions and grows in USDA zones 5-9.

'Royal Blue'
This rhizomatous perennial has divided dark green foliage and forms a clump. From mid to late spring produces small deep blue flowers that are rosy purple on the outside up to 25 mm (1 in) wide. It is suitable for coastal and inland regions and grows in USDA zones 5-9.

'Vestal'
This rhizomatous perennial has divided dark green foliage and forms a clump. From mid to late spring produces double white flowers up to 25 mm (1 in) wide with a central pom-pom like cluster of tepals. It is suitable for coastal and inland regions and grows in USDA zones 5-9.

'Wilks' Giant'
This rhizomatous perennial has divided dark green foliage and forms a clump. From mid to late spring produces very large single white flowers that are up to 50 mm (2 in) in diameter. It is suitable for coastal and inland regions and grows in USDA zones 5-9.