The Blue False Indigo Plant

by Ed Barnett

The blue false indigo, Baptisia australis, has been in my garden for about six years and has been one of the most reliable and beautiful herbaceous perennials of them all. The leaves are unique and handsome, the flowers are purplish blue with a touch of gray, and the seed pods, Wallowed to mature, are jet black and can be used in flower arrangements.

A native of the south central and eastern United States, this plant will grow in zones three to nine in average, dry, to medium wet soil in either full sun to partial shade. However, it prefers fill sun and moist, rich soil. The blue false indigo plant features indigo colored flowers that in form resemble the lupine and annual sweet pea, but are not fragrant. The flowers are held in erect racemes atop flower spikes that extend well above the clover-like, bluish green leaves. The leaves can be two and one half inches long but are often shorter. The seedpods, up to two and one half inches long, possess great ornamental interest. Pioneer children once used the seedpods as rattles, as the black hard seeds will clatter noticeably inside the seed covering. The early Americans also used the purplish flower as a dye for clothing in lieu of the true indigo plant of the West Indies.

I acquired my plant in an unusual way. While visiting a herbarium in Ohio in the autumn, I saw the Baptisia for the first time and stole about a dozen of the seedpods. The seeds, after having been soaked for a day, readily germinated in a pot but grew very slowly. One year later in the fall, the plants were a few inches tall but had developed a good root system. It was then planted in a location that received about eighty percent sunlight. In the early spring, it bolted and produced a few flowers. As of this Mother’s Day 2003, it is fifty-four inches tall and about forty-eight inches wide. The stems bear the foliage in great density, from the very base of the plant, about fifteen inches in diameter, to the top. I counted at least sixty flower spires that ranged in length from twelve inches to twenty inches! If cared for properly, the flowers have a vase life of about six days. Additionally, the plants attract bumblebees and the seeds will feed the birds in winter. The plants tend to sprawl in the summer but this can be handled by permanently erecting a heavy decorative metal stake at the initial planting. The stems will grow naturally through the tines of the stake. The stake will also mark the location of the plants in the winter so they will not be trampled upon. In the summer, the stems can be tied around with strong twine so that annuals can be planted underneath. Alternatively, a little of the excessive foliage can be sheared oft’, much as one might prune an unruly shrub, to allow the sunlight to penetrate to the ground. In December, after a heavy frost, the stems will collapse like the peony. The dead foliage should then be removed and disposed of. The Baptisia is deep rooted, long lived, slow growing, and will never invade the garden. The plants can be divided in the late fall or winter but deeply resent this treatment. If a new plant is desired, it might be best to replace the old planting with a new one. The foliage is remarkably pest free and disease resistant.