When you see a Christmas cactus burst into a range of pink, red, and white hues, you can be sure that winter is around the corner, as that’s their typical blooming period each year.
But sometimes it can also surprise you with flowers during the hot summers.
A Christmas cactus can bloom out of season and more than once a year when it has been exposed to shorter periods of light and cool temperatures.
In this article, we will explore the life cycle of the Christmas Cactus and what makes it bloom out of season. We will also show you how you could coax your Christmas cactus into displaying its spectacular colors all year round.
Blooming cycle of a Christmas Cactus
To understand what makes a Christmas Cactus (Schlumbergera bridgesii) bloom, it is important to first understand its life cycle because it typically blooms after a period of dormancy.
The dormancy period is crucial for the Christmas cactus to bloom because it allows the plant to rest and rejuvenate.
In their natural habitat of the Brazilian rainforests, Christmas cacti bloom during the short-day months of the year, when daylight hours are reduced. This is typical during late fall and early winter, hence the name “Christmas” cactus.
The timing of the natural blooming season is significant because it corresponds with the plant’s inherent biological rhythms. Blooming is a crucial part of the plant’s reproductive process, and in the wild, it is synchronized with the availability of pollinators and optimal growing conditions.
Blooming out of season may signal that the plant’s natural rhythms have been disrupted. It could also lead to stress for the plant, as it uses considerable resources to produce flowers, potentially at the expense of overall health and growth.
Therefore, it’s essential to understand and replicate the plant’s natural growing conditions as closely as possible to ensure a healthy, thriving Christmas cactus.
What makes Christmas cacti bloom out of season?
Stressful conditions can cause Christmas cacti to bloom in March, June, or August, which is outside of this usual blooming season in late November to late December as a survival mechanism.
This could be due to large fluctuations in temperature, inconsistent watering, a major change in the plant’s environment, or even repotting.
1. Fluctuations in light exposure
Christmas cacti require a consistent period of darkness for blooming. An unexpected change in the light-dark cycle can disturb the plant’s internal rhythms and potentially prompt out-of-season blooming.
Thus, consistent and controlled exposure to light and darkness is vital to maintain the plant’s regular blooming cycle.
2. Temperature fluctuations
Temperature plays a significant role in the blooming process of a Christmas cactus.
In the wild, this plant blooms during the cooler months, and maintaining similar conditions at home can help stimulate the blooming process.
Drafts or fluctuations outside of the ideal range of 50-55 degrees Fahrenheit (10 – 13 degrees Celcius) during dormancy can confuse the plant and trigger blooming at unusual times.
3. Overwatering or underwatering
A change in watering routine can stress the Christmas cactus and cause it to bloom out of season.
Both overwatering and underwatering can stress the plant as it tries to adjust. Overwatering or poor soil drainage can also lead to root and stem rot, which can cause a Christmas cactus to bloom out of season.
4. Repotting and Root Disturbance
Repotting can disrupt the Christmas cactus’s root system and cause significant stress to the plant, which might lead to blooming out of season. Because Christmas cacti prefer to be pot-bound, frequent repotting can disturb their regular blooming cycle.
5. Plant identity
Finally, it’s possible that your “Christmas cactus” is actually a different but related species, like a Thanksgiving cactus (Schlumbergera truncata) which blooms around November, or an Easter cactus (Schlumbergera gaertneri) which blooms in spring usually around Easter.
The Christmas cactus can be identified by its smooth, rounded edges on its leaf segments, whereas the Thanksgiving cactus has pointed, claw-shaped projections on the leaf edges and an Easter cactus has small fibrous hairs along the leaf edges.
Also, the Christmas cactus tends to have flowers hanging down like a pendant and the petals usually arch backward, whereas the Thanksgiving cactus has similar flowers but with a more asymmetrical form and the Easter cactus has star-shaped and upright flowers.
How to make a Christmas cactus bloom during the year?
Many gardeners actually want to coax their Christmas cacti to bloom during the year by mimicking the conditions for blooming.
Reduced light exposure
Christmas cacti can be induced to produce flower buds by reducing their light exposure to around 12-14 hours of uninterrupted darkness per day for about 6 weeks.
This can be done simply by putting it in a closet at 6 p.m., taking it out in the morning, and then moving it to bright indirect light until 6 p.m., and repeating the process for six to eight weeks. Smaller Christmas cacti can be covered with a box to block the light. Direct sunlight should be avoided because too much sun can scorch the leaves.
The plant has an even higher possibility to set buds when the reduced light exposure is combined with cool night temperatures between 55-65°F (13-18°C) and warm daytime temperatures.
Experiments have proven that Christmas cacti can be coaxed into blooming throughout the year even during the hot tropical summers of central Florida (with temperatures ranging from 22 to 32°C) (Poole, 1973). This was achieved by exposing the plant to light for a shorter period of 9 hours daily instead of a longer period of 13 hours for at least 6 weeks. Plants that were under shorter periods of light for 4 to 8 weeks began blooming for 9 to 14 weeks.
Correct watering habits are crucial in maintaining the plant’s health and normal blooming cycle. During dormancy, less frequent watering encourages the Christmas cactus to bloom. Conversely, during the growth stage, more regular watering is necessary. Maintaining these cycles can prevent the Christmas cactus from blooming at unusual times.
To keep the blooms fresh, lightly mist the cactus when it is blooming. Mist in the morning so it dries off by nighttime.
Avoid repotting during blooming
Avoid transplanting your Christmas cactus while it is blooming, because they actually bloom better when they are pot-bound.
Never transplant more often than once every four years. If you do repot them, move up just one pot size. Use a well-draining cactus soil, or add sand or perlite to regular potting soil for better drainage.
By understanding the life cycle of a Christmas cactus, and by mimicking its natural habitat with respect to light, temperature, and watering, we can ensure the plant’s health and normal blooming patterns. Moreover, with careful manipulation of these factors, it’s possible to coax your Christmas cactus into blooming more than once a year, adding a pop of color to your indoor spaces all year round.
Poole, R. (1973). Flowering of Christmas Cactus During the Summer. American Society for Horticultural Science. Vol. 8 (3), pp. 186. https://journals.ashs.org/hortsci/view/journals/hortsci/8/3/article-p186.xml