|Tolerant of either wet or dry soil, this easily grown perennial has loads of double white flowers in summer. Good in naturalized settings or rock gardens. Plant in full sun. Grows to an average height of 1 to 2 feet tall and wide. Keep moist until completely established and then the plant will need only average moisture. Fertilize in spring before new growth begins. Very little pruning is needed, but you should divide every 2 to 3 years.