Inquiring horticultural minds want to know if there are differences among the plants we refer to collectively as holiday cactus, said Candice Miller, University of Illinois Extension horticulture educator.
“These plants are often sold under the names of Thanksgiving cactus, Christmas cactus and Easter cactus because they are often seen in flower around these particular holidays,” said Greg Stack. “But are they different?
Yes, they are different, and the greenhouse growers who grow all kinds of flowering seasonal gift plants know how to make these plants produce flowers at just the right time of the year. “And, once you own one of these cacti, you, too, can make it re-flower at just the right time of year,” Stack said.
The difference among these three cacti is in the stems. While those green flat pads may look like leaves, they are really stems. The margins on the stems of the true Christmas cactus are rounded with scallops (usually four) along the edges. The plant also tends to be more arching and pendant in habit. The Thanksgiving cactus has stem margins that bear two to four saw-toothed, upward-pointing projections on the sides of the stem. And, finally, the Easter cactus has stem margins that are smoother than either the Christmas or Thanksgiving cactus and have hair like bristles at the tips.
“Another thing to note about these plants is that they are not very demanding,” Stack said. “All three need just about the same type of care. Even though they are members of the cactus family, they are probably in better company with orchids and bromeliads. That is because they are considered jungle cactus, and their needs for light, moisture and temperature are different than the cactus you see out in the desert.”
When buying one of these plants for indoor decoration, it will probably be in flower. Putting it in a location that is well lit and cool will help to extend the bloom period. Under very warm, low-light conditions, flowers will very quickly fade and fall from the plant. Water when the soil feels dry to the touch. If it has a decorative foil wrap on the pot, make sure the foil has holes to allow excess water to drain.
“After it has finished flowering, put it in a very bright, sunny location, water as needed, and fertilize with a half-strength liquid houseplant fertilizer perhaps once a month,” Stack recommended. “After all danger of frost is past in your area, locate the plant, pot and all, outdoors. Place plants in a partially-shaded location, keep the soil uniformly moist, and fertilize once a month.
“Even though this is a member of the cactus family, it likes soils that are a bit moister and a little protection from the sun,” Stack added. “Repotting should not be necessary for quite a while as these plants actually flower and grow best when they are pot bound.”
Stack said certain steps have to be followed to make them flower again.
“Getting the plant to re-bloom will rely on you manipulating day’s length and temperature,” Stack explained. “Both Thanksgiving and Christmas cactus depend on cool temperatures and short days to set flower buds. Easter cactus will bloom with cool temperatures and normal day length exposure.”
To get them to bloom around the holiday periods, start short days around September. Put the plant in a cool area, ideally 50 to 55 degrees. Give the plant bright light for 10 to 12 hours and total darkness for 12 to 14 hours each day. This means no light, artificial or natural. Put the plant in a spare room with no light, moving it in and out of a closet each day or covering the plant at night with several thicknesses of brown paper bag.
Stack said it is also important to reduce water and not to fertilize. Do this for six to eight weeks while buds form. When tiny pinpoint buds appear at the ends of the stems, the plant can be moved to a sunny, cool location. Resume watering to complete the blooming process.
To avoid the short-day treatment, both the Thanksgiving cactus and Christmas cactus will set flower buds if 50- to 55-degree temperatures are maintained during the fall. A cool porch kept above freezing would be ideal.
“Holiday cactus also can become a treasured member of the family,” he said. “These plants can live for many years if given good growing conditions.”
They are also plants that are passed down from one generation of gardener to another. “A plant that I received in high school in the mid-1960s still rewards me with flowers at the holidays,” Stack said. “Such a cactus is truly a gift that has the potential to keep on giving for many years.”
From the Dec. 19-25, 2012, issue