The much-loved Christmas cactus is a member of the small genus Schlumbergera, which contains only six species. Native to the rainforests of southeastern Brazil, Christmas cactus does not tolerate temperatures below 50°F. While Christmas cactus is generally considered a very low maintenance plant, getting it to bloom does require some attention. The bloom season starts in late fall, and the duration depends on some very particular demands being met.
There is another member of the genus Schlumbergera, known as Thanksgiving cactus, which blooms about a month earlier than Christmas cactus. Some sources claim that the key to distinguishing between the two are the stems (phylloclades). Allegedly, Thanksgiving cactus stems have distinct saw tooth serrations, while Christmas cactus stems have nicely rounded serrations, but that doesn’t seem to be hard and fast rule.
Schlumbergera blooms occur in a wide range of iridescently beautiful single colors and combinations thereof – white, pink, red, purple, orange, lavender, and peach. The bloom season typically lasts four to six weeks, with individual flowers lasting six to nine days.
Because of their gracefully arching stems, Christmas cactus work very well in hanging pots or baskets. Christmas cactus prefer to wear a pot that’s just a size too small, but not weighed down with a heavy planting medium. Schlumbergera are epiphytes, meaning that in their native habitat, they draw moisture and nutrients from whatever sources happen to be available, so they thrive wedged in among rocks or in the crooks of tree branches. Repotting is recommended every three or so years, using a light mix of planting media, such as two parts peat moss mixed with one part potting soil and one part sand or perlite.
Christmas cactus prefer light shade and temperatures between 70-80°F from April through September, when exposure to full sun will cause the plants to turn yellow. Flower buds are set in fall, and exposure to prolonged or excessive warmth during this period will cause the buds to drop from the plant. Once the buds are set, Christmas cactus requires bright light during the day, followed by 13+ hour nights between 55-65°F, for eight successive weeks, to induce blooming. In winter, the plants can handle bright sunlight, but require cool night temperatures to prevent blossom drop. Since Christmas cactus is an epiphyte, it does not like wet feet at all, especially during winter. Keep the planting medium on the slightly dry side, but do not allow it to completely dry out.
After the holiday festivities (aka flowering), a resting period is required, from late January to late March. Water very occasionally during this time, being careful to not dry out the planting medium completely. Remember, these beauties thrive in humid tropical rainforests. Find a cool place where the temperature remains in the mid to upper 50’s °F. In September, the plant will need another resting period, with daytime temperatures as close to 68°F as possible, until the flower buds are fully formed, usually by mid-September.
During the growing period (April to September), feed lightly with a dilute (quarter strength) fertilizer solution. Monthly feedings until early fall will sustain growth, and less frequent feedings are appropriate for fall and early winter.
Here’s a list of the most commonly occurring oopsies with Christmas cactus.
- If watered too much, the roots will rot.
- Flower buds are prone to dropping due to sudden changes in temperature or light, excessive dryness, or because the plant has just popped out more buds than it can support.
- Without the required uninterrupted long night periods, the flower buds may fail to open.
- Keep an eye out for the usual houseplant pests – aphids, mealybugs, scale, and spider mites – and keep them in check.
In addition to Schlumbergara, there are Rhipsalidopsis (also from the Brazilian rainforest, which bloom in April and May), and Epiphyllum (from Central American rainforests, some with scented blooms in spring and summer). Each one of these rainforest cacti groups provide beautiful flowers for your indoor garden, and under the right conditions, outdoors.
If you’ve never seen a hearty Christmas cactus in full bloom, you should really try to obtain a healthy specimen full of flower buds. Add a bit of Brazilian rainforest beauty to your holiday season.
This link, from the Royal Horticultural Society in the UK, offers advice on more advanced plant care and propagation, along with some advice that differs entirely from that offered by the Missouri Botanical Garden or Chicago Botanical websites, which may or may not be applicable here in Georgia. If the advice makes sense for your growing conditions, give it a try. https://www.rhs.org.uk/advice/profile?pid=840
This link provides in-depth information regarding the nutrient requirements of both Thanksgiving and Christmas cactus. http://www.clemson.edu/extension/hgic/plants/indoor/flowering/hgic1554.html
This link provides care and maintenance information on a wide variety of indoor cacti, including Schlumbergara, Rhipsalidopsis (aka Easter cactus), and Epiphyllum (aka orchid cactus). https://www.clemson.edu/extension/hgic/plants/pdf/hgic1502.pdf
This link provides care and propagation information regarding Epiphyllum. https://www.rhs.org.uk/advice/profile?PID=103
Header image: This gorgeous Christmas (or is it Thanksgiving – let’s split the difference and just call it a holiday) cactus features iridescent flowers with pure white hearts and smoldering deep burnt orange and cherry red margins. (Photo © Topnat – Fotolia.com)