Buy cardinal flower at nurseries throughout the year in mild climates and in spring through summer in colder regions. Choose plants that show active new growth in spring. Plant cardinal flower in full sun or, in hot areas, in partial shade. Plant in soil that stays moist. Plant cardinal flower in back of lower-growing perennials and ground covers on the border with shrubs and other perennials.
Cardinal flowers make a flashy contrast to purple and yellow flowers.
Make sure the planting area does not dry out. Fertilize each spring with a light application of organic fertilizer. Cut back the old stems to the ground in fall or late winter using bypass pruners. Be careful of any new growth that shows. Cardinal flowers prefer to grow in constantly moist conditions, and so they are a perfect choice for near a bog or in a wildflower garden.