Rising 2-4 ft. high from a woody base, blue wild indigo is a bushy, robust perennial. Flowers are blue-purple and pea-like, congested in dense, upright, terminal spikes, 4-16 in. long. Leaves are divided into three leaflets. In late fall the plant turns silvery-gray, sometimes breaking off at ground level and tumbling about in the wind.
Like other members of the pea family, this plant requires the presence of microorganisms that inhabit nodules on the plant’s root system and produce nitrogen compounds necessary for the plant’s survival.