Prepare the planting site in the spring, after the last frost. Remove the weeds and turn a 3-inch layer of organic compost into the site. The site should get partial sun (four to six hours daily) and have a neutral pH.
Insert the seeds into the soil until they are totally covered. Space the seeds 16 inches apart or farther. Water until the soil settles.
Continue watering frequently enough to keep the soil moist during the growing season. Reduce watering in the winter. Cover the root zone with a 3-inch layer of compost or mulch in the fall to keep the roots warm.
Cut off any frost-damaged or dead foliage in the spring. Deadhead the flowers during the growing season by pulling off the blooms as they fade.