Among the wide array of blooming houseplants, the Christmas cactus is one that stands out as weirdly exotic, with its spiny, fleshy foliage and dozens of delicate blooms that appear at the tips of the segmented stems once every year. If you’ve had any variety of Schlumbergera (the plant’s botanical name), you already know it’s an easy-care plant that stays quietly green most of the year, but really puts on a show during the fall or winter holidays. If you’re experiencing your first Christmas cactus, here are tips to help you enjoy this unique plant.
First, a clarification: a common name is Christmas cactus, or you may hear of Thanksgiving cactus or the more generic “holiday cactus.” And what you think of as a plant that blooms at Christmas may actually surprise you by showing off at Thanksgiving or earlier.
They are actually two different types of plants. Schlumbergera bridgesii is the botanical name for Christmas cactus, and it usually does flower around Christmas. But there is also S. truncata, or Thanksgiving cactus, which normally blooms about a month earlier.
How do you tell the difference? Look at the stem segments. If the margins have two to four sharp serrations along each edge, the plant is Schlumbergera truncata, the botanical name for Thanksgiving cactus, which blooms slightly earlier. If the segments are more rounded, the plant is S. bridgesii, Christmas cactus. That’s the one more likely to bloom in December or later. And one other distinguishing factor: When the flowers open, look at the pollen-bearing anthers. The anthers of Thanksgiving cactus are yellow; those on Christmas cactus are purplish-brown, according to plant experts.
Both are photoperiodic plants – they respond to the change in proportions of light and dark, and begin to form buds as days shorten and nights begin to get longer. Blooms open a few weeks later.
In general, both types of cacti thrive indoors in bright light and a moderate amount of water, so allow the soil to dry out a little between waterings. A plant that stays too dry for too long will suffer, though, so don’t neglect it completely. In the book The Complete Houseplant Survival Manual, houseplant expert Barbara Pleasant suggests once-a-month feeding with an all-purpose fertilizer in winter.
This tropical species is native to Brazil, and they grow as epiphytes in tree branches in shady rain forests. In our four-seasons region, they enjoy being outdoors in summer, but bring them indoors when nighttime temperatures get down to 40 to 50 degrees – and certainly before frost. Place them in a cool, dark room, and bring them out into bright light when buds begin to develop.
Schlumbergera is a long-lived plant that you can enjoy for many years, even a decade or two. It also propagates easily from stem cuttings – or from stem segments that have accidently been knocked off the plant: Place the segments in a small pot of soil, burying at least one segment, and care for the cutting as you would a mature plant, with regular watering. It should take root in four to six weeks.
One other thing to know about Thanksgiving/Christmas/Holiday cactus: when the plant is full of buds, it sometimes seems to resent being moved, so once it’s placed in a good spot for winter, try to avoid moving it. “Once plants begin blooming, they may drop their blossoms if exposed to any kind of stress,” Barbara Pleasant writes. A stable environment should keep those blooms going longer.
Check out the variety of tropical houseplants in the Garden Center at Gardens of Babylon.