Perennial. Pink flowers appear in mid to late Summer. 
To germinate, needs 30 days cold, moist stratification. 
Full to partial sun.
Medium to wet soil. 
Grows 2' - 4' when fully mature. May or may not bloom first year. 
Space plants 1 1/2' to 3 feet apart. 
USDA zones 3 to 9
Host plant for monarch butterfly larvae.