Every plant has a story and false indigo (Baptisia australis) is no exception.

A long-lived, sun-loving perennial of the legume or pea family, false indigo is the most common of 35 species of the genus Baptisia. It is native to the prairies, meadows, open woods and stream sides of the eastern and central United States. Plants graced early American gardens, including Thomas Jefferson’s Monticello.

Colonists grew baptisia in their gardens as an inexpensive indigo substitute after Cherokee Indians taught them to extract a blue dye from its roots. Southern colonial farmers produced it to make up for a shortfall in the supply of true indigo when trade routes to Asia were inaccessible. These farmers were paid incentives by the British government, the first example of an American agricultural subsidy.

Named the 2010 Perennial of the Year by the Perennial Plant Association and one of the top 200 plants of the last 200 years by the Royal Horticultural Society, false indigo is sadly underused in today’s gardens.

Its foliage emerges in early spring, followed by deep purple-blue lupine-like flowers blooming on foot-long stems for three or four weeks in May and early June. Its compound foliage is a gray-green and attractive all season long. Established plants soon become a sturdy bush 3-4 feet tall and 4-5 feet wide, so make room for their strong presence in the garden.

By early summer, brownish-purple seed pods appear and remain until the plant dies back in autumn. Pods will dry and their seeds can be heard rattling in summer breezes. The seedpods also are popular in dried floral arrangements. Seeds may be collected and sown, although any resulting plants from hybrid species will have variations in bloom color. Remove the pods if you don’t want seedlings. Plants are herbaceous (non-woody) and will blacken and collapse after hard autumn frosts. Debris can be removed during the end-of-season garden cleanup.

Hardy to USDA zones 4a-8 and tolerant of most soils, false indigo spreads by rhizomes. Plants are anchored by thick taproots extending deep into the soil, making mature plants drought tolerant. Like other legumes, it fixes atmospheric nitrogen into the soil, lessening the need for fertilizer applications. Baptisia should be sited in sun and is best left undisturbed. They may be relocated in summer, taking care to preserve their extensive root system.

Deer- and rabbit-resistant, the flowers attract bees and butterflies and host caterpillars of several butterfly and moth species. The plants can be used as specimens or massed for effect and make a great foliar background for other plants in a perennial border.

Plant breeders became aware that baptisias hybridize across their species and saw an opportunity to develop plants with altered growth habits, flower color and, perhaps, bloom time. In 1997, Tony Avent, owner of Plant Delights Nursery at the Juniper Level Botanic Garden in North Carolina, and Hans Hansen, owner of Shady Oaks Nursery in Minnesota and director of new plant development at Walters Gardens in Michigan, traveled to several states of the Great Plains to collect specimens of wild baptisia species.

Avent was focused on breeding for taller varieties with vase-shaped growth and long flower stalks. Hansen’s goal was to develop shorter, compact varieties with long flower stalks in a range of colors. Specimens from their trip also were shared with Jim Ault at the Chicago Botanic Garden.

After more than a decade of crossing and back crossing selected seedlings and in-ground trialing at their nurseries and botanic gardens, Avent, Hansen and Ault introduced named hybrids that resemble B. australis in size and culture but can stand without staking, have more prolific flower spikes and bloom in a Crayola box of colors.

Avent has introduced the Tower series; Hansen’s selections are sold under the trademarked brands Decadence and Decadence Deluxe and Ault’s Prairieblue plants are marketed through Chicagoland Grows.

Cultivars are varied, including ‘White Gold’ with chartreuse foliage and creamy white flowers; ‘Grape Taffy’ with reddish-purple blooms; and ‘Pink Truffles’ with clear pink flowers. Bi-colors include the mahogany and yellow flowering ‘Honey Roasted’ and ‘Lunar Eclipse’, whose lemon-cream flowers age to a medium to dark violet. Now, the only decision a gardener has to make is which color to choose.

The research team at Mt. Cuba Center, a nonprofit botanical garden in Delaware, evaluates native plants and cultivars in its trial gardens for horticultural and ecological value and issues reports about those deserving of greater use in home gardens. From 2012-2015, 46 selections of baptisia were evaluated to determine which plants performed best in the Mid-Atlantic region. The report may be read online at mtcubacenter.org.

False indigo plants can be found at local garden centers, particularly during their bloom times of May to early June.

Online sources

Bluestone Perennials: www.bluestoneperennials.com

Plant Delights Nursery: www.plantdelights.com

White Flower Farm: www.whiteflowerfarm.com

Elise Ford is a Penn State Master Gardener. This volunteer program supports the outreach mission of Penn State Extension and provides research-based information on best practices in sustainable horticulture and environmental stewardship. Information: alleghenymg@psu.edu 412-482-3476.

First Published: June 16, 2023, 9:30 a.m.