Baptisia tinctoria - False indigo

Baptisia tinctoria, the dyer's baptisia, is a wild false indigo with yellow flowers, lighter and shorter than many hybrids. Its rounded habit, blue-green dissected foliage and small luminous clusters give a natural look to dry borders, flower meadows and large sunny borders. This perennial takes its time to establish, but lives for many years without requiring much care, even in very cold regions and poor soil.

This species belongs to the family Fabaceae, like peas, brooms and clovers. Its official vernacular name is dyer's baptisia; one also finds false lupin, false indigo, wild indigo and indigo lupin in horticulture. Its main botanical synonyms are Podalyria tinctoria, Sophora tinctoria, Baptisia gibbesii and Baptisia tinctoria var. crebra. Baptisia tinctoria is native to North America, from southeastern Canada to the north-central and eastern United States. In the wild, this species grows in open woods, dry woodland edges, fields, savannas, sandy heathlands, open pine forests and stony or poor ground. It is a herbaceous deciduous perennial: its stems die back in winter, then regrow from the stump in spring. It forms a branched, rounded clump, 60 to 90 cm tall in flower. In poor soil, it remains more compact; in deep, well-drained soil, an older plant can spread further. Its growth is slow in the first few years, as the plant develops a deep, fleshy and fragile taproot. This root gives it good drought resistance, but makes established plants difficult to move. The leaves are formed of three small entire leaflets, medium green to blue-green, with fine texture. Flowering occurs from May to June, sometimes until July depending on the climate. The flowers, bright yellow to cream-yellow, typical of Fabaceae, show a banner, two wings and a keel. They are small, around 1 to 1.5 cm, but numerous, gathered in short clusters and erect above the foliage. This flowering attracts especially bumblebees and wild bees. After flowering, the flowers produce small swollen pods, first green, then blackish when ripe.
The name Baptisia comes from a Greek word related to dyeing, and the epithet tinctoria refers to the same use: this plant was used as a substitute for true indigo, but the dye obtained was a less intense blue-black.

In the garden, Baptisia tinctoria is planted in full sun, in lime-free soil that does not retain water in winter. It is used to vegetate dry slopes, sunny borders and meadows, particularly in poor or sandy soils. It can be paired with the grasses Schizachyrium scoparium 'Standing Ovation' and Sporobolus heterolepis 'Cloud' as well as the Aster ericoides f. prostratus 'Snow Flurry' which flowers at the end of the season.