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A Prickly Situation- Christmas or Thanksgiving Cactus?

Christmas cactus blooming now? It may be because you’ve got a Thanksgiving Cactus! Or did it bloom last Easter and you thought it was confused? That may be because you had an Easter cactus, not a Christmas cactus.

Yes, our favorite Christmas blooming cactus has a whole bunch of relatives, who bloom at different times of the year. A lot of people may know these as Zygocactus. However, the botanists have decided they belong in the genus Schlumbergera. Since the plants were first noted by plant explorers in the early 1800s, they’ve been called Zygocactus, Schlumbergera, Epiphyllum and Hatiora. Now, the botanists seem to agree that they all belong to the Schlumbergera family. It gets more convoluted as growers breed and hybridize within the group, introducing named varieties.

Christmas cactus, Thanksgiving cactus and Easter cactus are all different species, each with a specific bloom time which has resulted in their common names. Europeans call the group crab cactus, due to their habit and form, South Americans call some of them May flowers, due to the bloom time. They originated in Brazil, found at higher elevations not far from the south eastern coast, with excellent humidity. They often grow in, surprisingly, part shade as a forest cactus as opposed to a desert cactus. They will be found growing on living trees as epiphytes (like orchids) or in rocky outcroppings full of leaf litter and moss.

The ‘Holiday Cactus’ group are distinct with their flat stems that look like fleshy leaves or pads, somewhat rectangular, attached end to end. The Thanksgiving cactus, Schlumbergera truncata, and Christmas cactus, Schlumbergera bridgesii, look quite similar except the pads of the stems have deeper indentations on the Thanksgiving cactus. The Easter cactus has been known as S. gaertneri, (also known as S. buckleyi, Rhipsalidopsis gaertnerii and Hatiora gaertneri) has a much more rounded leaf section.

Regardless of what it’s called you want to keep your cactus happy, healthy and re-blooming every year. I know of plants sixty years old, so this can become a living heirloom in your family. Like many cacti and succulents, the plants like to be root bound, or big plant in small pot. Don’t be too anxious to pot up from the container you bought the plant in. It may be two to three years before potting up is necessary, and then only to a slightly larger pot. They like a well-draining potting mix, something for cacti and succulents is appropriate. These forest cacti do not like to dry out completely, which can produce wrinkling on the pads. When they are in bloom water regularly but do not keep it wet. They prefer a bright room but not in direct light. You can certainly put it outside for the summer, in a shady area but do not let it get touched by frost. Harden it off gradually, as you would any houseplant or greenhouse grown annual, but first getting it outside for short periods, slowly increasing the length of time. Too much sun causes the pads to turn red.

The trick to re-blooming involves both cool temperatures and limited light. Fortunately, that’s quite easy for us Manitoba gardeners. The plants need eight hours of light and sixteen hours of dark to stimulate bloom. Have it out in a bright room from, say, 9 to 5, then into a closet or unused room for the rest of the day. Blooming is also stimulated when temperatures are cooler at something between 15 and 18 o Celsius (60 to 65 F). It takes about six weeks for a Thanksgiving or Christmas cactus to set buds. Once returned to the main living area, many plants experience bud drop. The biggest reason is probably drafts, both warm and cold. Do not keep your Holiday Cactus by a fireplace or furnace vent, or by an often used outside door or on cold windowsill. Rooms that are too warm will cause bud drop, as will direct sun or overly bright rooms. And do not over-water at this time, allow it to dry out somewhat between watering. Do not fertilize at this time.

Your Holiday Cactus will grow and add new pads through spring and summer. This is the time to be fertilizing. These plants, like most cacti and succulents, prefer light fertilizing so use a house plant food like Schultz ™ at half strength once a week. Our ‘Cactus Love’TM is an excellent fertilizer, including some of the micronutrients that cacti need. Holiday cacti have a high need for magnesium sulfate so you can replace one weekly watering with Epson salts: 1 teaspoon in a liter of water. Magnesium deficiency and general poor health will be indicated when little roots grow out between the pads or the pads turn purple. Stop fertilizing in August and prepare to use light and temperature control to initiate budding.

Preparing the Holiday Cactus to bloom can be a great learning activity with children. The lush, airy blooms are such a joy during our cold, white winter. As your children or even grandchildren may inherit your plant, it’s best they be prepared to enjoy it for years, don’t you think?


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