The night blooming cereus is a name shared by several members of the cactus family, primarily Hylocereus undatus and Selenicereus grandiflorus. Each of these cacti is notable for its briefly spectacular flowers. These plants are also known by such wildly descriptive names such as the moon flower, lunar flower and the queen of the night. A night blooming cereus blossoms for only a single evening, but in that time, the flowers spread 1 foot (about 30 cm) or more in diameter. By morning, they are withered and do not revive.
Different varieties of the night blooming cereus all flower in a similar fashion. Buds begin to sprout along the stem in summer. These buds grow quickly, and as they mature, gardeners will have to watch closely for a hint of white at the tip of the bud. This is a sign that the flower is nearly ready to open.
The flowers open in the evening, fast enough that the motion can be seen. Most varieties produce large, white flowers, but some hybrids have been cultivated to produce colored petals. Like other plants that flower at night, the night blooming cereus is a fragrant flower, with a scent similar to vanilla. This scent helps to attract nighttime insects for pollination.
By morning, the flowers wilt and wither. The flowers do not regenerate, and after the buds have blossomed, the plant will not flower until new buds grow during the following year. Some gardeners report cutting and chilling these flowers to delay wilting, but even refrigeration will postpone withering by only a day or so.
Hylocereus undatus is originally native to tropical regions of Central and South America. During most of the year, the night blooming cereus is described in terms ranging from unremarkable to just plain ugly. The fleshy stems have a triangular cross-section, with spines growing from the ridges. The plant is likely to cling to surfaces and climb like ivy if given the chance.
Selenicereus grandiflorus comes from the Caribbean and Central America. This plant has slender, round stems covered in vertical ridges and slender spines. These stems initially are green but turn slightly purple as they mature.
Most often, night blooming cereus plants are grown from clippings rather than seeds. These are fast growing plants, and trimmings can be taken without causing harm. Cuttings take root quickly and are easy to grow. A 2-4 inch (5–10 cm) length of mature stem can be cut, put it in sandy soil and moistened. The plant should take root within three to six weeks.
These plants are native to tropical regions and do not tolerate cold weather. In regions that experience annual frost, these cacti should be grown as indoor potted plants. Indoors or out, the night blooming cereus does best in full sunlight. It requires very little attention, and in fact, it is likely to do better with less attention, and care should be taken to avoid over-watering it.