Winner of the RHS Plant of the Centenary at Chelsea Flower Show 2013
Large (up to 5cm across), saucer-shaped, violet-blue flowers with white centres appear throughout the summer above the mounds of slightly-marbled, deep green foliage. Perfect for underplanting roses, or filling a few gaps in the front of a border, it copes well in full sun or partial shade.
Garden care: In midsummer rejuvenate plants that are beginning to look jaded, by removing old flowered stems and leaves. Lift and divide large colonies in spring.