|The cultivar, 'Dark Knight' pairs very deep blue-violet flowers to dark silvery leaves.
C. clandonensis is a deciduous shrub that has bright blue to purple, late summer flowers that attracts butterflies. Flowers appear on new growth, so cut back hard to the ground early each spring. Foliage is narrow and grey-green and is mildly fragrant as are the flowers and stems. Thrives in moderately fertile, well-drained soil, in full sun or part shade. Grows to 3' wide and 5' tall.