Northern Prairie Wildlife Research Center
Also called "fragrant false indigo", dwarf wild indigo is found throughout North Dakota, and is especially common in the eastern two thirds of the state. Elsewhere, the plant ranges from western Minnesota to southern Saskatchewan south to New Mexico and Kansas at elevations up to 7,200 feet.
Dwarf wild indigo is a smooth, much-branched perennial from a woody rootcrown. Plants are usually about 12-18 inches tall. Leaves are found on the upper half of the plant and are about two inches long. Each leaf is comprised of 8-15 pairs of small, oval leaflets arranged along a midrib. Several dozen violet-to-purple flowers are crowded into spikes about one half inch wide that form in the upper branches. The tiny pods (legumes) are smooth and glandular.
Look for dwarf wild indigo during late June in native prairie on gentle slopes at middle or low elevations. Plants are usually more abundant where grazing is light or moderate. Some of the larger wild indigoes were used by Amerindians for bedding and to keep butchered meat clean, but I found no references to uses for the small species discussed here.
Dwarf wild indigo is a member of the bean family (Fabaceae) which contains about 10,000 species of herbs, shrubs, and trees of which many are of great economic importance. Fab means "bean" in Latin. The generic name Amorpha is from the Greek amorphos, "deformed", in reference to the absence of four of the normally five petals in members of this family. There are about 20 species in this genus and most are found in the southern states. Nana means "dwarf" in botanical Latin. Dwarf wild indigo was first described for science by the English botanist-naturalist Thomas Nuttall in 1813. He visited the Mandan villages in what is now North Dakota in 1810-1811.