Wide spacings help control disease problems and maintain maximum flower size. Full sun is preferred but light shade is acceptable. Cut back old flower stems to prolong the blooming period. Dieback occurs if plants are not divided often enough. Removal of weak shoots enhances flowering on stronger shoots.
Propagation is by seed, root cuttings, division and softwood cuttings.
The seed germinates in 3 to 4 weeks at 70 degrees but needs darkness. Seed sown in the fall germinate the following year. Collected seed may produce off types. Root cuttings be are obtained by digging up the clump in fall and removing large roots to within 2 inches of the crown. Cut them into 2 inch lengths and place them a half inch deep in sandy soil.