Indigo plants (Baptisia) are often called False Indigo or Wild Indigo. They are perennial plants that are hardy in zones 3 to 9 and grow from 3 to 6 feet tall and just as wide. Indigo are well-placed in the back of a border or garden or in a wild, naturalized setting. There are two varieties: Baptisia australis, which has pea-like blue flowers; and Baptisia alba, which has white flowers.
Place these plants in a relatively permanent location as transplanting is not advised, due to the abundant taproots. Flowers bloom in early summer, and the dried seed pods are attractive in arrangements. Historically, the indigo plant was used to make blue dye.
Caring for Indigo plants
Choose a location that has full sun and well-drained fertile soil. If planting seeds, soak them overnight. Seeds can be planted in spring or fall. Spacing should be about 3 feet apart. Water the seeds often until
For container-grown plants, spring is the best time to plant, after the last frost. Spacing is the same as in Step 1. Water after planting.
To encourage another bloom, deadhead the spent flowers before the seed pods form.
Taller varieties, such as B. australis, may need to be staked, especially after a heavy rain.
Flowers of indigo plants can be used in floral arrangements. When the seed pods form in late summer, they can be dried and used in dried flower arrangements as well.
Pruning is not necessary with these plants, but they may be cut back in the fall to promote a healthy start in the spring.