Cardinal flower is a herbaceous perennial that may grow four- to five-feet tall. It is easily grown in rich, medium to wet soil in full sun to part shade. The soil should never be allowed to dry out, and It will tolerate brief flooding. Although it will tolerate full sun in northern climates, it appreciates partial afternoon shade in hot summer climates of the lower Midwest and South. Root mulch should be applied in cold winter climates to protect the root system and to prevent root heaving. Mulch will also help retain soil moisture.