Argyreia nervosa 

Argyreia nervosa is a perennial climbing plant, native to the East Indies and Bangladesh, now widely cultivated in Hawaii.
It reaches up to 10 meters in length.
Leaves are green, large, heart-shaped, pale green underneath.
Due to its beautiful appearance, the plant is used for ornamental purposes.
Flowers are pink-purple-white, inside the calyx red-pink.
Requires rich, airy soil. Prefers a sunny position.