Pure white flowers, the size of a dinner plate, open as soon as the sun goes down and stay open all night, then close in the morning. This wondrous sight is also a heady experience because of the intoxicating fragrance. Night Blooming Cereus blooms in waves during the summer months, with sometimes as many as 15 flowers open at once. Nature's ability to manifest such a magnificent creation leaves us in awe of this wonderful epiphyllum. As for all members of the Orchid Cactus family, a period of dryness and cool nighttime temperatures in the winter ensures summer bloom.