Perennial types are best planted during cooler months in spring or fall. For biennials and annuals, plant nursery starts outside in spring, or sow seed indoors 6 to 8 weeks before your last frost date for bloom the same year. Seeds sown directly in the garden in late spring or summer will bloom the following year.
Where to plant
Choose a site with rich, well-draining soil in full to part sun. Plants will bloom best in full sun; too much shade can result in fewer flowers and crown rot.
How to plant
Place plants 6 to 12 inches apart, depending on the variety. Loosen soil to a depth of 12 inches and mix in 2 to 4 inches of compost. Dig a hole twice the diameter of the root ball and place the plant in the hole so the top of the root ball is level with the soil. Gently tamp soil around the base of the plant and water well.