Moonflower Seeds. Moonflower is a robust climber that produces beautiful, fragrant, pure white flowers up to 12.5 cm (5″) across The flowers open quickly during the night and last through to mid to late morning. Each flower only lasts for a short time, but once flowering starts it continues right through to very late summer and even well into fall in milder zones. Numerous decorative heart shaped leaves make this variety suitable for use as a screen. Quick growing vines will readily wrap themselves around any decent support.