H4 in. x W12 in. From a mound of deep green, birch-like leaves, lax stems reach out in early summer, tipped with reddish buds that open to large white bells. This species from Armenia is good tucked into rock walls; sun or partial shade. Hardy to Zone 6.

These justly popular rockery plants have differing needs, but are always rewarding. Most spread readily with underground runners or creeping stems; others are saxatile alpines, best grown in deep grit with a gravel collar. In general, they prefer gritty, well-drained soil and full sun to partial shade.