Night blooming cereus plants (Epiphyllum oxypetallum and Hylocereus undatus) are epiphytic plants with flowers that open for only about 12 hours at night. Each flower opens for a few nights in a row before fading. The long, flat, succulent leaves provide a tropical flair during the day while the fragrant flowers offer a special treat to enjoy while unwinding alone or with that special someone after the kids are tucked in for the night.
Night blooming cereus are tropical plants that are hardy only in U.S. Department of Agriculture plant hardiness zones 10 and 11. They are OK if the temperatures drop down near 30 degrees Fahrenheit for only a few hours but are seriously damaged if the cold temperatures last any longer. For this reason, they are usually grown as houseplants. They can be grown outdoors during the summer, though. Temperatures that stay between 50 and 100 degrees Fahrenheit are ideal.
Due to their long stems, night blooming cereus are grown in hanging containers. Indoors, they should be hung in an area with very bright, indirect light or in an east-facing window where they will be exposed to cool morning sunlight. Outdoors, they can be hung from tree branches, porch roofs or overhangs where they get bright or dappled shade, although brief early morning direct sunlight is fine. While they can be planted on a tree crotch in mild climates, they should be left in their containers so they can be quickly moved indoors if the temperature drops unexpectedly or if strong winds suddenly kick up.
Night blooming cereus potting mix should not be allowed to dry out completely. When they are hung outdoors in the summer, they may need to be watered every day. Indoors and in cooler temperatures, they may only need to be watered once or twice each week or only once or twice each month. Check the soil often and pour room-temperature water over the potting mix until it drains from the bottom when the top one-third of the mix becomes dry. Increase the humidity by running a humidifier or setting a shallow baking dish with pebbles and water in it if the air is dry. Misting the plant with room-temperature water each morning can also help.
Fertilizer and Re-Potting
Give the night blooming cereus a weak solution of water-soluble fertilizer every two weeks. In the winter and spring, give it a 2-10-10 or 0-10-10 fertilizer to encourage blooming. When it finishes blooming, switch to a 5-5-5 or 10-10-10 fertilizer for the summer and fall. Mix only 1/4 teaspoon of fertilizer into 1 gallon of water or dilute it to half the recommended strength. Re-pot only after the night blooming cereus becomes pot bound. This usually happens every seven years or so. When the potting mix dries unusually quickly, roots are growing out of the bottom and the plant looks top-heavy, it is pot bound. Re-pot it into a container that is one size larger and use a fast-draining potting mix. A mixture of two-thirds sphagnum peat moss and one-third perlite with 2 tablespoons of orchid bark and bone meal mixed in is ideal.
Night blooming cereus are sometimes bothered by aphids, mealybugs and scale insects. Set the plant in a tub or sink or set it outdoors and hose aphids and mealybugs off the plant with water if they become a problem. Scrape scale insects off with a thumbnail or wipe them off with a cotton ball soaked in rubbing alcohol. Mealybugs can also be removed with a cotton ball and rubbing alcohol. Caterpillars, slugs and snails may also try to make a meal out of a night blooming cereus. Remove them by hand if they appear. Fungus gnats will also sometimes attack these plants. Remove broken leaf segments and other debris from the top of the container to help prevent them. Letting the potting mix dry a little more before watering will usually eliminate the fungus gnats if they become a problem. Check the plant carefully for insects and pests before taking it into the house if it has been hanging outdoors.