"Queen of the Night" is the nickname given to a species of Selenicereus, a family of tropical cacti. The species, S. grandiflora, is notable for its huge (up to a foot long), trumpet-shaped flowers. The flowers are heavily fragrant and bloom at night, when they are pollinated by bats, according to New Zealand Gardens. Although the flowers live for just one night, a healthy plant can bloom numerous times during the growing season.
Queen of the Night are tropical plants native to Cuba and Jamaica. In the United States, they only grow on the Hawaiian islands, according to the U.S. Department of Agriculture. They are also found in the Virgin Islands and Puerto Rico. In cooler climates, they must be grown indoors.
These cacti cannot grow in rich, loamy potting soil, warns the Plant Care website. They need very loose, well-draining soil. A commercial potting mix works well, as long as it is high in perlite or coarse sand, humus and crushed rock. Queen of the Night grown in containers need pots that have drainage holes in the bottom. These plants thrive when pot-bound.
Light and Temperature
These plants need plenty of sunlight. Indoor plants should be placed where they are exposed to sunlight from the south or west. Normal indoor temperatures are fine for these plants, but keep them away from cold or hot drafts.
Selenicereus grandiflorus, as a tropical plant, should be watered with lukewarm water. Rainwater is best, as tap water may contain fluoride and other minerals that can cause salt to build up in the soil. Distilled water may also be used. The soil should dry out between each watering. Watering should be reduced greatly at the start of fall, and the plant placed in a cool, dark location so it can go dormant during the fall and winter (October through early March). These plants can then be brought back into sunlight in the spring, when they will begin to grow again with regular care.
Plants grown indoors can be bothered by the same insect pests that plague all houseplants, such as spider mites, scale and mealy bugs. Inspect your Queen of the Night plant often and rinse off these pests with a strong stream of water. Stem rot can occur if the planting medium is kept overly wet.