Wild indigo, false indigo, or Baptisia (Baptisia spp.) is a long-lived U.S. native perennial (USDA hardiness zones 4-9). Plants are deeply tap-rooted and will reward you for many years of multi-seasonal beauty. They’re sometimes mistaken for Carolina lupine (Thermopsis caroliniana).

Modern day cultivars are hybrids of 8 Baptisia species. Top four species are purple (B. australis), lavender blue (B. minor), white (B. alba), bright yellow (B. sphaerocarpa). Several bicolors are also available. Baptisias are in the Pea family (Fabaceae). Long-blooming baptisias last for 3 to 4 weeks in the spring garden. Their blue-gray foliage and sturdy upright shrubby habit are pluses in the summer garden.

Long-lived baptisias perform at their best in full sun. In the shade they bloom less and stems are weak and frequently require staking. Tough deep-rooted wild indigos do not like their soils disturbed. Baptisias prefer a deep humus-rich well-drained soil but tolerate most average soils. Mulch with organic matter to keep the soil cool and weed-free.

Vigorous plants grow 3 to 4 feet high and 4 to 5 feet wide after 3 to 5 years. Do not overcrowd. Newly planted baptisias should be watered until established, usually within 1-2 year. Plants are slow to establish and begin blooming with only a few flowers in their first year and are heavily flowered within 3 to 4 years. 

In early spring add 1-2 handfuls of a slow-release fertilizer around new plants. Older well-established plants require little to no fertilizer as they produce their own nitrogen. Yellowing of leaves in the summer is a symptom of iron deficiency or high soil pH. In such cases, feed with chelated iron or an acid-based fertilizer like Schultz™ or Miracid™. Established plants are heat and drought tolerant and are almost invincible to disease and insect problems.

Stunning stalks of colorful pea-like, non-fragrant flowers appear in mid-spring. Cut blooms last 3-4 days indoors. Flowers stalks give way to black seedpods by late July. Black capped chickadee, finches, and sparrows will feed on seeds. Gardeners may opt to remove the seed pods before they mature. Flower arrangers utilize the ripe blacken seedpods in arrangements.

Cultivars with the deeper shades of blue and yellow blooms stand out in a garden. Popular cultivars from North Carolina sources and Chicago Botanical Garden breeders include: ‘Purple Smoke’ (lavender flowers), ‘Solar Flare’ (yellow), ‘Alba’ (white), and ‘Twilight Prairie Blues’. Walters Gardens in Michigan developed the Decadence™ Series which are pictured above.

Further reading: view the MT. Cuba Baptisia Trial Report