If there’s one plant that’s ubiquitous in big-box stores, it’s the Christmas kalanchoe! You’ll see them in tiny pots as well as in more modest containers and floral arrangements, but they almost always have one thing in common: clusters of four-petaled flowers galore! These flowers can remain in good condition for several weeks, and the plant itself is very easy to keep alive.
Choosing the level of difficulty for the kalanchoe poses a problem. Of course, keeping it alive or even in bloom is no major challenge, and the plant does very well in our homes. Getting it to bloom again, however, requires a little more skill. We’ll talk about that in this article on Kalanchoe blossfeldiana, which you might know as flaming Katy, Christmas kalanchoe, florist kalanchoe, Madagascar widow’s-thrill or the flaming Katy.
Origin
This plant, native to Madagascar, is a member of the Crassulaceae family, which comprises 30 genera and almost 1,400 species. Other well-known Crassulaceae plants in our homes include the jade plant, sedums and echeveria.
K. blossfeldiana is not the only kalanchoe grown in our homes. In fact, the Kalanchoe genus comprises over 150 species, some of which are commonly found in our homes such as the panda plant or the mother of thousands.
Like its hairy cousin, K. blossfeldiana is native to Madagascar. It’s known as the Christmas Kalanchoe, since its flowers appear in our homes in the dead of winter (like the poinsettia or Christmas cactus).
Botanist Michel Adanson gave the plant the name Kalanchoe in his book Famille des plantes in 1763. He may have invented the name from scratch, or it may be a modification of Chinese words meaning “that which falls and grows”, in reference to the prodigious asexual reproduction of K. daigremontiana (and others). Blossfeldiana was named after Robert Blossfeld, a German botanist and hybridizer. It is also sometimes called Blossfeld’s Kalanchoe.
Description
Kalanchoes are small, stocky, branching succulents. Their oblong leaves are smooth, with crenelated edges. In good light, the crenellations will be margined with red; otherwise, the leaves are a glossy, dark green. Foliage is evergreen.
The plant is not very tall, reaching a maximum height of between 30 and 45 centimeters (12-18 inches). The growth habit, particularly of modern cultivars, is dense.
When kalanchoes are in bloom, inflorescences grow in clusters at the end of a small, fleshy stem. Traditionally, the flowers have four red petals and grow in large groups, in quick succession.
Varieties
There are a large number of cultivars that are very difficult to distinguish from one another. The main difference is the color of the flowers. While they are traditionally red, flowers of different colors (orange, yellow, pink, magenta, white and even two-tone) can be seen on different cultivars. Most modern cultivars are also more compact than the species, reaching around 20 cm (8 inches).
There are also varieties that, instead of having four petals, can have… up to thirty-two! These double cultivars are also called Calandivas® (registered trademark), and were followed by Grandivas®, whose flowers are even larger. They resemble miniature roses and come in the same colors as the kalanchoe.
Although this article is not about other kalanchoes, it’s worth mentioning K. laciniata, another type of kalanchoe. It resembles K. blossfeldiana in every way, but the leaves are much slimmer and more slender, reminiscent of seaweed.
Growing Tips
Light
Kalanchoes need as much light as possible. While they can survive for some time in “only” bright light, they still prefer several hours of direct sunlight.
Watering
With their fleshy stems and leaves, kalanchoes offer excellent drought tolerance. Water them when the soil is deeply dry. They require a little more water when in full bloom (but not that much), and should be watered much less if not in full sun to prevent rotting.
Atmospheric Humidity
Kalanchoes prefer dry air reminiscent of their native climate. They are susceptible to leaf diseases and mildew if atmospheric humidity is too high.
Potting
If watered correctly (i.e. not too much), the kalanchoe is happy with traditional houseplant potting soil. However, it prefers a potting soil for cacti and succulents, as the addition of draining elements helps the soil dry out better.
When it comes to repotting, kalanchoe grows best in close quarters. As a small plant, it rarely needs repotting.
Fertilizers
During the growing period, it can be fertilized at a normal dose. Plants bought in bloom have been fertilized abundantly to ensure this spectacular flowering: it’s best to wait 6 months before fertilizing them again.
Temperature
Kalanchoes are tropical plants. While they can withstand brief drops in temperature to 7°C (45?), it’s best to keep them above 18°C (64?).
Maintenance
Kalanchoe is a low-maintenance plant. As a slow-growing plant, it requires only occasional pruning and even less repotting. So, especially at the end of winter, if it has etiolated growth due to lack of light, or if it refuses to branch out, terminal bud pruning can help it grow into a more compact, aesthetically pleasing form.
Finally, when the plant gathers dust, it’s better to clean it with a brush than under water, to avoid fungal diseases.
What About Flowering?
The kalanchoe is a so-called “short-day” plant, meaning that it is the diminishing hours of light that prompt it to produce its buds (which is why it usually blooms for the holiday season).
Kalanchoe is not easy to get to flower on purpose. Although it needs short days, it also requires a lot of direct sun to grow and, as with all plants, flowering also requires a lot of light. So give it less than twelve hours of direct sunlight, and darkness at night the rest of the time.
In our homes, artificial lights can confuse the plant, even if they’re not specifically grow lights.
That said, laidback gardeners don’t usually make life so complicated for themselves. The simplest thing to do is to let Mother Nature do her work: find the brightest window (in the northern hemisphere, these are the ones facing south) and place your little kalanchoe directly on its sill. When night falls, you naturally close the curtains, isolating the kalanchoe from any artificial light coming into the room. Provided your window is well insulated, temperatures shouldn’t drop enough to damage it. You should eventually see flower buds forming towards autumn.
Propagation
Kalanchoe can be propagated by taking stem cuttings. As with other succulents, these are best taken directly from dry sandy soil and placed in full sun. Start watering when the stems offer some resistance when pulled, which means they have begun to root.
Be careful if you propagate double-flowered cultivars: as they are in fact patented plants, you can’t propagate them for resale.
Problems
- When overwatered, they can start to rot. It’s best to take cuttings to give them a chance of survival;
- They can develop mildew in overly humid environments. Unfortunately, the affected parts must be removed;
- Scale insects, aphids and thrips can affect kalanchoe plants;
- If aerial roots appear on the stem, this is very common and not really a problem. They can be removed if they are a nuisance.
Toxicity
Kalanchoe is toxic and should not be eaten.
Purchasing Tips
Kalanchoes are mass-produced and generally inexpensive. This approach to quantity rather than quality means you need to be careful when buying. Once you’ve decided on the color of the plant’s flowers, go for the one with the most buds, to ensure a beautiful bloom. Then check the plant’s health: avoid any that have lost much of their foliage or whose leaves don’t look healthy. Don’t hesitate to pull lightly on the plant to make sure it’s well rooted. If you buy it during the cold months, don’t forget to protect it from the weather when you take it out of the store.
Finally, and this is now more my personal advice: really concentrate on the quality of the bloom when you buy it. Despite your best efforts, it will probably never flower again as spectacularly as it did the first time. If the shape of the plant is not optimal, you can prune it when the last flower has died, and it will have plenty of time during the spring and summer to grow into a more attractive shape. K. blossfeldiana can be considered an intermediate between a houseplant and a temporary flower pot.
Conclusion
Rather than throwing the kalanchoe into the compost after it has bloomed, why not simply continue to look after it? It then becomes an easy-to-care-for succulent green plant that, if well cared for, could also bloom again, for a second blooming holiday season! Isn’t nature beautiful?
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