May not bloom for several years after planting. Staking plants before they bloom is a good idea because flower heads are heavy. Plants bloom in late spring. Use balanced fertilizer after bloom. Foliage is very attractive and resembles a shrub from spring until late fall.
Clumps get bigger each year.
No particular growing problems. A wildflower is a plant which is a native American species. Wildflower plantings utilize native species, whether annual, perennial or biennial, from various areas of the country to create a natural-looking garden effect. Wildflowers have to be, since they have to take care of themselves. They bloom, go to seed, and disperse their seed onto the surrounding ground, where it takes hold and begins the cycle over again.