A popular blooming holiday plant is the “Holiday Cactus” which is an umbrella term to include the Christmas cactus (Schlumbergera bridgesii) and the Thanksgiving cactus (S. truncata). These are not cacti at all but epiphytes from the Brazilian rainforest. In their native environment, they grow among tree branches, in the humid, shady jungles.Both are grown the same way but the Thanksgiving one tends to bloom during November and December while the Christmas cactus tends to bloom afterwards. The Thanksgiving cactus has saw-tooth serrations on the “leaves,” while the Christmas cactus has round, lobed margins. The anthers of the Thanksgiving cactus are yellow while the anthers on the Christmas cactus are purple-brown.
If you have a blooming holiday cactus, keep the plant in bright indirect sunlight, keep the soil evenly moist, and provide a high humidity level. If you can keep the plant cool, like high sixties, you may be able to prolong blooms as long as 7 to 8 weeks. There is no need to fertilize in the winter while it is blooming.
In the summer, you can keep the plant indoors as a houseplant or move outdoors after danger of frost is over. Here in Virginia, I take mine out around Mother’s Day. I put mine in full shade first and then in a dappled shade area under a tree. If you first put the plant in direct light outdoors the leaves will have sunscald, which is unsightly but not deadly.
In the summer, the plant is tolerant of dry soil but very quick to become dry. These plants prefer to be pot bound and usually are in small containers that drain quickly. If you are relying on rain, it may be weeks between watering for the small plant and the soil may become too dry. Fertilize with an all-purpose houseplant food.
In mid-summer, pinch stems back to promote branching and to create more terminals for flowers. Also, this is a time to think about propagating the plant to give new ones to friends and families. Propagating is easy, see the steps below.
In the fall, bring back indoors before the first frost. To make it bloom again, in September, let the soil dry between watering and start to expose the plant to 5 to 6 weeks of short days. These are days in which the plant is receiving less than 12 hours of daylight. This means no artificial light after the 12-hour period so no lamps in the living room. Temperatures should be cool, below 55 degrees. When buds form, continue regular watering, bright indirect light, and cool temperatures.
Blooms are induced by “short days” and cool night temperatures. This happens naturally outside in the fall as the days shorten and the nights get cool but by the end of October a frost could kill the plant. If you leave the plant outside until the first frost and then bring inside, it should be triggered to bloom. If you have kept the plant indoors all summer long, you may have to artificially induce blooms. Either turn off lights and keep the plant in the dark after 12 hours and reduce the house temperature or place the plant in a dark and significantly cooler room every evening until buds form.
To propagate a holiday cactus, line up a few clean, small plastic containers such as yogurt containers, fruit cup containers, or plastic cups and puncture the bottoms to allow for drainage. Fill with packaged seed starting mix and water each cup so water runs through the drainage holes.
To take the cutting, simply twist off a piece of stem about three to four segments long. The stems are made up of joined rectangular segments. Each segment is called a cladode. The length should be long enough to insert into soil and stand up. You want to twist so you have the end of a segment or cladode, not mid-way into a segment. Insert into the container, water again, and tamp to ensure the stem is standing upright. You can insert several per container or just one per container.
Place on a tray, in a well-lit place, out of direct sun. The room should be warm, “room temperature,” not a cold, drafty basement. It is not necessary to place the container in a plastic bag or to fertilize.
Some people insert the cutting directly into the soil while others wait a day or two for the cut part to form a callus. This is done to prevent rotting. I have never had a problem with rotting so I simply insert the cutting into the wet soil.
A rooting hormone is not necessary; the plant roots easily. Remember these are epiphytic plants that grow on trees in Brazil’s coastal mountains. In their natural habitat, they have aerial roots, which is an indication that the cuttings will root easily without added hormones.
For the first few weeks, water the containers often enough so the soil is moist but not waterlogged. Because the containers are very small, the soil will dry out faster than a full grown plant in a large container. After a few weeks, check to see if roots have formed by gently pulling to see if there is resistance. Also, if the plant is still turgid, there is a good chance it has survived the cut and is still trying to form roots. If the plant is obviously wilted or rotted, throw away the entire plant and container into the trash. This is one advantage to having one cutting per container. If it does not work, you only lose the one cutting and container, not many cuttings in one container.
Eventually, the cuttings will form enough roots so you can transplant to a larger container with potting soil. For the cost of seed starting mix, cuttings are an inexpensive gift for friends and family. Makes a great teacher’s gift too!