The plants known as Christmas cactus and Thanksgiving cactus (Schlumbergera x buckleyi) are both popular fall- and winter-flowering houseplants. The genus Schlumbergera contains six species of tropical cacti native to rainforests in Brazil. These plants are easy to grow in a wide variety of colors and are great for decorating around the holidays. But because the plants look similar, many people are confused about how to tell them apart. Even garden centers and grocery stores can add to the confusion by mislabeling the cactuses.
During the flowering period, both plants produce tubular flowers that are red and pink with yellow pollen. The flowers resemble bells with tiers of curving “petals” that dangle down from the plant. The Thanksgiving cactus offers more colors of flowers and has a more star-like appearance to the petals than the Christmas cactus.
Both cacti need cool evening temperatures to promote bloom set and the flowers need a lot of darkness to open. If you want to encourage your cactus to bloom at the appropriate time for the holiday, place it in a dark room from September through November. This will also help the cactus to retain its foliage.
When the cactus does finally begin to flower, give it plenty of indirect light during the day and place it in a dark room at night. This will give the cactus its best chance of retaining its color and producing beautiful buds for your Christmas decorations. The cactus will require more watering during this time as it is preparing for the holiday. Water the cactus until the soil is moist, but do not let the soil dry out completely between waterings.
After the cactus finishes flowering, it will need less water. However, the soil should never be allowed to dry out completely. This will cause the cactus to become stressed and may stop it from producing any more buds or flowers.
Another way to distinguish a christmas vs thanksgiving cactus is by the segments on the leaves. The segments on the Thanksgiving cactus are more pointy and have jagged edges while the Christmas cactus has more rounded edges. The Thanksgiving cactus is sometimes also called the crab or lobster cactus because of its pointed leaves.
In recent years, gardeners have been creating new cultivars that blur the differences between the Christmas and Thanksgiving cactus species. These new hybrids are what you will find at most garden centers and grocery stores today. If you are interested in growing the true species-type of these cacti, it is possible to do so from seed. The only problem is that the true species-type cacti are slow to bloom and tend to be more difficult to care for than the modern cultivars. Therefore, many gardeners prefer the more common holiday cacti that can be found in the department store and grocery store aisles.