Thanksgiving Cactus or Christmas Cactus?
Your Christmas cactus is already in bloom, well before Christmas? That’s probably because you don’t have a true Christmas cactus (Schlumbergera russeliana and its hybrid, S. x buckleyi), but rather a “Thanksgiving cactus” (S. truncata ), so-called because it naturally blooms in November. Greenhouse growers produce Thanksgiving cactus by the millions in barely heated greenhouses designed to delay their bloom until Christmas. So when you buy them the first year, they bloom right on time. But the next year and the following years, no such luck: they bloom heavily, but in November.
The true Christmas cactus (S. russeliana and S. x buckleyi) can be recognized by its hanging stems with rounded teeth and fuchsia flowers that hang downwards. Commercial growers don’t appreciate its weeping stems because they mingle with those of its neighbors, making the plant hard to ship… and it is also more costly to produce, as it needs a heated greenhouse. It is often found in private homes, as it is a long-lived houseplant, but almost never in garden centers.
There are many varieties of Thanksgiving cactus (S. truncata) on the market ranging in color from pink to purple, red, white and yellow. They have stems that are generally upright in their youth, although they arch as they grow, and have distinctly pointed teeth, like crab claws. The flowers are carried slightly upright or horizontally. They are readily found in garden centers during the holiday season and also in supermarkets, box stores, and florist shops.
To delay flowering of your Thanksgiving cactus until Christmas next year, keep it cool, 60?C (15?C) or less, throughout the autumn. This is what the greenhouse growers who produce them do: by growing them in barely heated greenhouses, they manage to produce Thanksgiving cactus cheaply, just in time for Christmas.