Set plants 10 to 12 inches apart, or more for larger cultivars. Choose a location in full sun or very light shade; any reasonable soil, so long as it is well-drained, will do.
Periodically removing spent flowers will lengthen the blooming season. We recommend a mulch of humus or compost. Dividing every 2 or 3 years as it becomes necessary will induce stronger growth. Otherwise, plants are pest- and disease-free, requiring no special care.