The Poinsettia may be the most iconic holiday plant, but the Thanksgiving cactus is my favorite because of its sentimental value. About 18 years ago, I purchased what I thought was a Christmas cactus for my grandparents. They traveled for an extended period that summer and accidentally put the cactus in the outdoor shed. Thankfully, I had decided to do some landscaping while they were gone and discovered the sad-looking cactus before it was too late. Although both of my grandparents have passed away, I still have the original plant, which graces us with bright magenta flowers each year around Thanksgiving.
The flowering time is a clue that this treasured plant is not a Christmas cactus (Schlumbergera x buckleyi) but a Thanksgiving cactus (Schlumbergera truncata). In fact, I have yet to see a Christmas cactus on a store shelf, even if the tags say otherwise. In addition to the timing of flowering, there are other features that distinguish the two.
- The stem segments (phylloclades) on the Thanksgiving cactus have distinctly pointed edges, while the stem segments of the Christmas cactus are more rounded.
- The anther, which bears the pollen, is yellow on a Thanksgiving cactus but purplish-brown on a Christmas cactus.
If your holiday cactus isn’t flowering, it’s probably related to light. Holiday cacti are short-day plants. This means they require a period of uninterrupted darkness to trigger a bloom cycle. Indoor lighting and even streetlights shining through a window can interrupt the dark cycle required for flower formation. To flower, relocate your plant for 8 weeks to an area where it will receive 13 hours of dark daily.
One great characteristic of holiday cacti is the ease of propagation. A few years ago, I pinched several sections containing 3-5 stem segments, allowed them to callus, and placed them in well-drained potting soil. If something should happen to the mother plant, I will still have a piece of it and the treasured memories it holds. See HGIC 1554, Thanksgiving & Christmas Cacti for more detailed information on the care and propagation of these popular holiday plants.