This introduced perennial plant has a vine-like habit, producing stems up to 3' long that sprawl across the ground. The slender stems are hairless and become somewhat woody with age. The opposite leaves are up to 1¼" long and ½" across and evergreen, rather than deciduous. They are hairless, ovate, blunt-tipped, and smooth along the margins. Their upper surface is dark green and shiny, and their texture is rather leathery. The slender petioles are shorter than the blades of the leaves. From the axils of the upper leaves, there occasionally develops individual flowers on slender stalks up to 6" long. There is only a single stalk (peduncle) per leaf axil, which is slender, hairless, and leafless. Each flower is about ¾1" across, consisting of a corolla with 5 spreading lobes that are truncate or slightly notched along their outer margins. The length of the lobes on each side is slightly asymmetrical, providing the flowers with a pin-wheel appearance. The color of the corolla is lavender or light blue-violet. The throat of the flower has the shape of a 5-angled star that is white along the edges. The tubular green calyx has 5 slender teeth. It is hairless and much smaller than the corolla. The blooming period usually occurs during late spring and lasts about a month. The flowers are sparingly produced. From each flower that is fertilized, there can develop a pair of follicles (seedpods that split open along one side) that are long and slender. However, follicles rarely develop from flowers in Illinois. When they occur, each follicle contains several tiny black seeds that can be blown about in the wind. These seeds are without tufts of hair. The root system produces woody rhizomes and slender secondary roots. This plant can reproduce vegetatively through underground runners, or the stems above ground can form rootlets at the leaf nodes. It often forms dense colonies that exclude other species of plants.