This beautiful perennial native wildflower is a member of the phlox family. It grows in moist woods and along stream bottoms in much of eastern United States, but is most abundant west of the Appalachians. It is restricted to the mountains in the South.  The plants seem to prefer dappled shade conditions with moist high quality soil under deciduous trees.

The bell-shaped flowers bloom from April to August. They are light blue to purple, forming loose clusters with weak, slender stalks. The individual flowers are about 2/3 inch long and have 5 petals forming a corolla with flared lobes. The single stigma is long and protruding, making self-pollination difficult. The flowers persist for about 3 weeks. Both nectar and pollen are provided to pollinating insects. The fruit is a brown capsule with three seed chambers.

The plant grows to a height of 8-15 inches, though the stems have a tendency to lean to one side or sprawl across the ground. It has fibrous roots and spreads only by reseeding.

This species is sometimes mistaken for bog Jacob's-ladder (P. vanbruntiae).  Spreading Jacob's-ladder has fewer leaflets on its pinnately compound leaves (5-15), and is a smaller plant with a more delicate stem. Also the five stamens of the plant's flowers do not project beyond the corolla of the flower.