The Christmas cactus is one of those plants that triggers fierce arguments over its botanical name and whether it is a Christmas cactus or a Thanksgiving cactus.
This group of showy succulents called Holiday Cacti bloom during popular American holidays. Schlumbergera bridgesii, Christmas cactus, has notched edges but they are not pointed or toothed. Schlumbergera truncata has more notched stems (like a serrated edge) and blooms earlier, closer to Thanksgiving. Aside from the leaf differences between holiday cactus, both have tubular, brightly colored flowers. There is also the Easter cactus (Rhipsalidopsis gaertneri, formerly Schlumbergera gaertneri), which have smoother leaf edges with no notches, and need a much longer cool and low light period to form flowers. Easter cactus plants have flat, star shaped flowers, easy to set apart from the other holiday cacti’s elongated blooms. This plant blooms from March until May. There are around 300 hybrid varieties of these cacti, leading to even more species names. None of them are true cactus; they are succulents that grow wild in South American jungles.
About Holiday Cactus
Before you buy plants from local outlets, check them carefully to be certain they appear healthy and free of pests such as mites, mealybugs, and scale insects. There are many internet sources for buying plants by mail—simply do a search for holiday cactus or Christmas cactus. With proper care this houseplant can flower for thirty years or more.
Keeping your plant blooming
Do not place your Christmas cactus houseplant near a bright window. In their native habitat these plants grow in tree branches and rock crevasses as understory plants, so they prefer mostly filtered sunlight. Indoors, a bright window with a sheer curtain can provide optimal light. Morning sun is ideal. The plant favors temperatures between 60 and 70 degrees F (15–21 C), with average to high humidity levels. Keep the soil evenly moist during flowering. Placing a tray of pebbles filled with water beneath the Christmas cactus container is a good way to add more humidity to the home. Avoid exposing the plant to cold drafts, unvented heaters, or rough handling. Night temperatures above 70 F (21 C) may inhibit its bud development.
Displaying your plant
To encourage more stems, grow your Christmas cactus as a hanging plant or place it where it has room to drape. You won’t need to worry about touching thorny spikes as you do with other types of cacti.
Keeping a Holiday Cactus for next year
Moisture is important to the health of a Christmas cactus. The plant requires frequent and thorough watering during its active growth in spring and summer, with the soil staying slightly moist. Allow the plant’s moisture levels to drop and dry out some between watering intervals, but don’t let it dry completely. Never let the Christmas cactus sit in water, as this will lead to stem and root rot.
From June to August, feed your Christmas cactus using a good quality, balanced, soluble or granular fertilizer, such as a 10-10-10. If using full strength according to label directions, fertilize monthly. Otherwise, cut the fertilizer rate to about 25 percent of what is recommended on the label and fertilize with each watering. This will fuel the flower development and prompt your Christmas cactus to bloom by holiday time. The root system of the Christmas cactus is fine and shallow and can be damaged by overfertilization. Stop fertilizing in September to reduce vegetative growth and help stimulate bud formation on strong stems; resume fertilizing after the blossom period.
Outside, the plants will thrive on the north side of the home or on the north side of a fence or other building. This will provide the light screening necessary to keep the plant from burning. The Schlumbergera, or Christmas cactus, does not grow in special cactus soil. Instead, it needs well-draining soil that retains a bit of moisture. A mixture of one part potting soil to two parts peat moss and one part perlite is ideal. Alternately, potting soil mixed with orchid mixture or pine bark will provide a good medium.
Re-pot the plant when it’s really needed, but the cactus actually flowers best when it is pot bound. There are tell-tale signs of stress that include (1) reduced flower bud formation, (2) flower bud abortion, (3) reduced new stem growth, (4) shriveling of the younger stems even when well-watered, (5) “self-pruning” or dropping of younger stem segments, and (6) development of small, hair-like adventitious roots at the bases of many stem segments. Another sign of possible root loss is abnormally prolonged moisture in the soil because of the lack of healthy roots to extract soil moisture during normal transpiration. When repotting, choose a container that is only 1 to 2 inches bigger in diameter than the current one. A pot larger than that can retain too much moisture or invite insects and plant diseases. Pruning a Christmas cactus after it blooms may promote more blooms the following season. Cut sections with a sharp, sterile implement at the section joint. This will promote more branching at the cut.
