Michigan State University Extension
Ornamental Plants plus Version 2.0 - 00002102
01/01/98
Hardiness Zones: 3 to 7 Height: 5 ft Spacing: 3 ft Type: perennial or biennial Flowers: Blue
Comments: This is another short-lived perennial that can be treated as a biennial. Because the plant will self- seed it will give the appearance of a perennial. If volunteer plants are not wanted, be sure to prune off flower stalks before seeds can form and disperse. The flowers borne along the top part of a stem that can reach 6 feet. To keep the stalks upright, staking will be needed.
Propagation: Division may be done in spring or fall. Seed may be planted outdoors in late spring or early summer with flowering occurring the following year. The seed is fine and may be hard to handle. Seed planted indoors germinates in 2 to 3 weeks.
Cultivars: 'Alba' - White flowers.
References for Cultivars: White Flower Farm 1997.