Indigofera is a large genus of over 750 species of flowering plants belonging to the family Fabaceae. They are widely distributed throughout the tropical and subtropical regions of the world. Species of Indigofera are mostly shrubs, though some are small trees or annual or perennial herbs. Most have pinnate leaves. Racemes of flowers grow in the leaf axils. Most species have flowers in shades of red, but there are a few white- and yellow-flowered species. The fruit is a legume pod of varying size and shape.

Indigofera frutescens or River indigo as it is commonly known is an evergreen tree, naturally occurring along forest margins and other protected areas like gullies in and amongst grasslands. This profuse flowering shrub or small tree will reach a height of 1-2 meters and is therefore well suited to small gardens in temperate areas or large pots in areas where winters are severe.