Sweet Flag is a tall perennial grass with foliage similar to that of an iris. It is best grown in a damp setting with exposure to both sun and shade. Propagation is done by division in spring and fall. Leaves are harvested and dried in the fall, at which time the fragrance becomes more intense.
Sweet Flag makes a good edging or groundcover and works well in mass plantings, especially near ponds. Smaller varieties grow well in containers, as long as soil is never allowed to dry out. Leaves can be placed in a jar with sugar for a vanilla flavoring. They also make a nice potpourri. The rhizome is used to relieve acidy stomachs.