Slender Indigo is a small shrub growing to 1.5 m tall. The branchlets are grooved and covered with silky hairs. Leaves are pinnate with elliptic-oblong blunt leaflets, with the tip sometimes notched. The leaves are covered with prostrate hairs. Flower are tiny, purple-pink, typically 1 cm long, in long slender clusters. Sepals are brown-hairy. Pod is straight, swollen and hairless. Slender Indigo is found in the Himalayas at an altitude of 1300-2100 m. Flowering: May-August.