Set plants 15 to 18 inches apart in full sun or light, dappled shade, choosing a moisture- retentive, slightly acid soil high in humus. Firm soil down thoroughly around the roots and water in well.
Keep plants well-watered for the first few weeks after planting. When centers of the clump begin to die out and flower production goes down, clumps should be divided. This may occur every 6 to 8 years. When flowers have finished blooming, cut off bloom stalks. Remove dead foliage in fall.