Also known as Mariesii Grandiflora, White Wave is a small, compact deciduous shrub. It's foliage is deep green, which make a lovely backdrop for the flowers. These appear in summer. on large, lace-cap flower heads. Depending on your soil type the flowers will be either blue or pink. 

At a glance:

Deciduous foliage

Blue or pink flowers appear in summer

Full sun/partial shade

Well drained fertile soil

Hardy

Will reach a height of 1.5m and a spread of 1.5m over 5-10 years