'Prolific' is a vigorous, nitrogen-fixing deciduous climber up to 9m high with stems twining anticlockwise, pinnate leaves of 9-13 elliptic or ovate leaflets, and many very fragrant, soft blue-violet flowers in dense, hanging racemes 25-30cm long in late spring and early summer, often followed by bean-like seed pods; it often flowers from a young age, and the flowers are visited by bees in bright or warm weather