During the Holiday Season, Christmas Cactus are on display in garden centers. David Graper, SDSU Extension Horticulture Specialist and Director of McCrory Gardens, shared some information about these beautiful plants as well as tips for extending their beauty beyond the season.
Although it is often sold labeled as Christmas Cactus or Holiday Cactus, Graper said there is actually a difference between the true Thanksgiving Cactus and the true Christmas Cactus.
“Often times we will see hybrids of these two different plants. Both of these plants have flattened specialized stems that are actually part stem and part leaf, called cladodes. Here is where some of the differences show up,” he said, going on to explain that the Thanksgiving Cactus, Zygocactus (Schlumbergera) truncatus, has wider flattened stems with a few pointed projections or serrations to the tip of the cladodes.
“The flowers are usually bright pink, purple, white – often edged in pink or a golden yellow color. The true Christmas Cactus, usually Schlumbergera bridgesii have somewhat narrower stem segments with more rounded tips to the cladodes,” Graper said, adding that there is also an Easter Cactus, Rhipsalidopsis gaetneri, with wider cladodes, tipped with a fringe of several hairs.
Graper said all of these plants are photoperiodic, which means that they perceive the length of the night.
“When the night or dark period gets long enough, they initiate flower buds and bloom,” he said.
According to Graper, the Thanksgiving cactus usually flowers earlier than the Christmas Cactus followed later by the Easter Cactus, as the nights start to get shorter again. In order to have them ready in time for the holidays each year, Graper explained that producers of these plants control the length of the dark period using either lights to shorten or shade cloth to extend the length of night.
“These holiday plants are members of the Cactus family, but they usually are associated with habitats that are more like jungles than deserts,” he said. “They are native to South America where they are often found growing on rocks or tree trunks and branches.”
He went onto explain that jungle cacti like these prefer to have regular watering as opposed to long periods of drought. However, probably the most common problem in growing these plants, Graper said is watering too frequently or letting the plants sit in water.
“This will usually result in bacterial or fungal infections of the roots which will essentially shut down the flow of water from the roots to the rest of the plant. Grow them in a well-drained potting soil and let the soil dry out slightly before watering thoroughly,” he said.
Graper said that unlike some holiday plants, like the poinsettia, which are best recycled in the compost pile after its done flowering; the Schlumbergera, like these, can be long-lived plants that are quite easy to bring back into bloom for many holidays to come.
“I have relatives that have very large Christmas Cacti that are up to 4 feet across that they have had in the family for decades,” Graper said. “These large plants can be covered with hundreds of flowers when they come into bloom.”
For best results, Graper said the plants grow best in bright, indirect light or morning sun but should not be grown in full sun all day long.
“Some people will move these large plants outside during the summer but they can easily be kept on a sunny windowsill all year long,” he said. “The key to getting them to bloom again is to place them in a cool location, maybe down to 60 degrees at night, and let them be exposed to the normal day/night cycle of light and dark. This way they will perceive the lengthening dark period and come into bloom, right on time for Thanksgiving or Christmas.”
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Propagation is quite easy with all of these plants, especially in the spring, Graper said.
“Select healthy stem segments about 3 to 4-inches long. Use a sharp knife or just break them off the main plant. Let them sit out for a day or so, to allow the wound to callus a bit, then stick them into your potting soil, about an inch deep,” he said.
Then he added to be careful not to water too much until the plant shows signs of new leaves growing out of the tips or there is resistance when gently tugging them out of the soil.
“It is usually best to plant multiple cuttings in a single pot to provide a fuller look and more flowers to enjoy for each plant. Fertilize your new plants with a half-strength houseplant fertilizer about once a month from spring until fall, then hold off on fertilizing again until the following spring,” he said.
He added that if you are looking for that holiday gift that can keep on giving, consider a holiday cactus. These plants can usually be found in 4 to 8-inch pot sizes at a reasonable price. To learn more, visit iGrow.org.