Christmas or Thanksgiving cactus the Christmas cactus and the Thanksgiving cactus (Zygocactus or Schlumbergera) have been popular holiday plants for over 100 years. The original species have been hybridized so that now, growers bring them into bloom as needed, thus the name “Holiday Cactus”. Control of day-length and night temperatures is used to induce flowering at the appropriate time. They may live for 20 years or more, and are often passed down from one generation to another.
These beautiful plants come in a wide variety of flower colors, from white to gold or yellow, salmon, pinks, red, fuchsia, and bi-colors. True cacti, they are composed of short, leaf-like segments forming gracefully arching stems, with the unusual flowers borne at the ends of the “branches.” These epiphytes (plants that live up in trees) are native to the humid tropical rain forests of South America, and thus need more moisture than a desert cactus, as well as protection from mid-day sun. Care varies with the seasons.
When in bloom, flowers will last longer if the plant is kept in a cool, bright location, away from drafts or heat vents. Allow the soil to dry moderately (up to ¼ the depth of the root ball) between thorough waterings. Do not let roots stand in water.
After flowering, allow the plant to rest for a few weeks; that is, cool temperatures (50°F to 65°F) and less water. Over the spring and summer, keep the soil evenly moist, not wet, and provide good drainage. Fertilize with a flowering formula every two to three weeks. Plants can benefit from the higher humidity of a summer outside under the trees. While bright light promotes good flower bud development, strong midday sun can burn the leaves.
In the fall, keep plants drier and cooler. If your plant is a true Thanksgiving cactus, it will probably bloom sometime in November, and a true Christmas cactus will bloom in December or early January. To induce flowering for a specific holiday, begin a short-day, cool night regimen six weeks before you wish to see buds. For example, you might start the treatment in mid-September for Thanksgiving flowering and in mid-October for Christmas. Buds take a few weeks to open. A cool window sill, away from a heat source, can also induce flowering. Most holiday cacti will flower on their own, eventually, so if you don’t care when they bloom, just sit back and let nature take its course.
Like many flowering plants, Zygocactus will flower best if moderately pot-bound. Repotting is usually only required every two to three years, and should be done in the spring. To promote more branching, prune the plant in the spring, removing a few leaf segments from longer stems. These leaf-segments can be used to start new plants by rooting them in a light, well-draining potting medium, such as vermiculite, coarse sand, or seed-starter mix. Bud drop is usually caused by over-water or very dry air. Consider placing the plant on a saucer filled with damp pebbles to increase the humidity immediately around the plant.