|Clump forming perennial with light blue, star-shaped flowers are present from May through June. Requires very little care in moist, fertile soils. Grows to 2 feet tall and 18 inches wide. A wonderful border plant. When using this plant in flower arrangements,sear end. Take care, as sap is poisonous. This is one of few perennials that has fall color; leaves turn yellow. The American Horticulture Society ranks this as one of their top 75 great plants for the garden.