Clematis terniflora (Sweet Autumn Clematis) is a plant in the buttercup family, Ranunculaceae. It is native to Asia (China, Japan, Korea, Mongolia, Russia (Siberia), Taiwan), but is cultivated in gardens and has naturalized in parts of North America. It is considered an invasive plant in some locations.
Clematis terniflora is a vine with opposite, pinnately compound leaves, on climbing stems. The flowers are white, borne in fall. They usually bloom in September in the Northern hemisphere. The blooms are nicely fragrant and visited by bees. Source