(Editor's Note: This article was originally published on October 19, 2009. Your comments are welcome, but please be aware that authors of previously published articles may not be able to respond to your questions.)
This group of Crassulaceans has some of the most spectacular succulents as well as some of the most annoying weeds of all the succulent plants. Some Kalanchoes grow into enormous tree-like structures while some remain as moderate sized suckering shrubs, and still others seem to only grow a few inches tall. I am not clear on what makes a Kalanchoe a Kalanchoe, and I sometimes get the smaller ones confused with Crassulas, their close relatives. For the purposes of this article, plants in the genus Bryophyllum are included with the Kalanchoe and I think that's the accepted taxonomy as of today (maybe not next week, though).
3 other plants in the family Crassulaceae that can sometimes be confused with Kalanchoes: Echeveria hybrid (left); Aeonium nobile (right) and Crassula cotyledonis (below)
My introduction to Kalanchoes was with an infamous plant, one of whose common names is Mother of Thousands. Ignoring this ominous common name, I was captivated by the highly ornamental leaf (that's all I was given) with the jaw-like serrations along the edges and the beautiful mottling of dark and light green. Doubting I would be able to grow such an exotic-looking plant, I was told to just set it on some semi-moist soil and wait. Imagine my surprise when it indeed started to grow into a happy, healthy plant. It never looked back... literally. For the next 6 years I spent hours each month trying to eradicate this plant from my greenhouse as well as my cactus garden with no success. Be careful what you wish for.
Kalanchoe diagremontiana aka Mother of Thousands
That experience had somewhat tainted my enthusiasm for collecting Kalanchoes for many years, but it shouldn't have. Most other species are far from invasive, and some are even impossible for me to keep alive for more than just a few months. Some are beautiful, some are just odd. Most are worth growing.
Kalanchoe is an Old World genus of 150 to 200 species with the bulk of species in cultivation originating from Africa and Madagascar. However there are a number of Asian species in cultivation as well. One of the things that sets Kalanchoes apart from other members of the Crassulaceae are having 4 petals instead of 5 (it amazes me what separates plants sometimes.) All species have succulent leaves, some fuzzy, some smooth. The fuzzy ones seem more tolerant of high heat like I get in my garden, while the smooth-leaved ones are less tolerant of full, hot, dry sun, and may require sun protection to survive. This generality does not hold in all cases though (for example one form of Mother of Thousands excells in the hottest and driest conditions despite having smooth leaves).
three examples of Kalanchoe flowers: Kalanchoe bracteata (left), Kalanchoe blossfeldiana (middle) and Kalanchoe eriophylla (right, or bottom)
More Kalanchoe flowers Kalanchoe marmorata (left) and Kalanchoe diagremontiana x delagoensis (right)
Some Kalanchoe leaves: huge, dissected, fuzzy leaves of Kalanchoe beharensis (left), small, smooth, shiny leaves of Kalanchoe bracteata and super fuzzy small leaves of Kalanchoe eriophylla (right, or bottom)
Many Kalanchoes are easy to grow and are very drought-tolerant, though few are very frost-tolerant and none can survive much freezing. However I grow about a dozen species, and there are dozens more in the local botanical gardens here in Southern California where freezes do occur fairly frequently. So obviously some tolerate a bit of freezing.
Three Kalanchoes in my yard that went through the 25F freeze a few years ago... Kalanchoe beharensis survived though got badly damaged (left), but Kalanchoe synespala (middle) was completely destroyed; Kalanchoe tomentosa (right or bottom) was virtually untouched
Some species of Kalanchoe are noted for their toxicity, and though this is one of nearly 1,000 species of toxic plant I have growing in my garden, some of these Kalanchoes are among the few half dozen or so toxic plants I grow that I truly do have concerns over pet poisoning potential. However, actual cases of Kalanchoe toxicity in small animals are rare in the literature and I personally have never seen one. Some Kalanchoes contain very toxic cardiac glycosides and reportedly only a small amount ingested can cause serious cardiac (heart) repercussions. Some species have a sedative property and one even has a form of toxin that has shown some cancer-producing activity but also has been used as a medicine for many years. Most also produce marked gastrointestinal effects including vomiting, bloody diarrhea and cramping. There is no antidote for Kalanchoe toxicity, but generally symptomatic treatment is successful.
There are many dozens of species of Kalanchoes and I cannot touch upon them all here, but the following is a brief discussion of some of the more common species that I have some experience with.
Kalanchoe beharensis, or Felt Bush, is one of favorite species and one of the more dramatic landscape Kalanchoes in cultivation. This plant can actually become a large shrub or even a tree in the right climate, growing up over ten feet tall. It is one of the fuzzy-leaved species, but the leaves on this one can get to large- up to a foot long or more, and nearly as wide. Stems become gnarled, twisted and covered with bizarre, ornamental leaf scars. And old, tall plant is truly a piece of living sculpture. Flowers are unimpressive. This plant is one of the most heat tolerant of all the Kalanchoes tolerating the hottest, drying sun my climate can throw at it. It comes in several cultivars, some with bronze or copper fuzz, and some miniature varities. Cold tolerance is not great, but at least down into the high 20Fs.
Kalanchoe beharensis in landscape (left); dwarf form in my yard (middle); copper colored variety called Chocolate Chip (right, or bottom- photo Happenstance)
old plant in botanical garden (left); Disneyland planting of mature plants (middle, or left); flowers (not grown for its flowers) on right or bottom
Kalanchoe ‘Fang' is a Kalanchoe beharensis hybrid (possibly with K. tomentosa, some claim?) that is a much shorter plant, and certainly a less vigorous grower, but a common one in cultivation. This plant has heavy, succulent very fuzzy leaves with teeth-like knobs over the leaf surface (the "‘fangs," perhaps?)
Kalanchoe blossfeldiana, aka Christmas Kalanchoe, could be the most popular Kalanchoe from a potted plant standpoint. One can find this species at most nurseries, even those not specializing in succulents. It is a green-leafed plant grown for its brilliantly colored flowers, which there must be a dozen or more varieties in cultivation now. I don't find it a particularly interesting species otherwise and it is not an easy garden plant in my climate (way too cold sensitive and does not like hot sun). But it makes a fairly hardy potted plant, requiring little water to keep alive. However, it does seem to require at least some regular watering should one want it to bloom. From a pet toxicity plant, this is the number one Kalanchoe, too, and one should be careful to keep pets from this species. I am not sure why animals would like to nibble on it; perhaps it is not as bad tasting as most toxic plants tend to be.
Photos of Kalanchoe blossfeldiana at several Southern California nurseries
Kalanchoe delagoensis, aka Kalanchoe tubiflora or the Chandelier Plant but also sometimes called Mother of Thousands (like the related plant below), is--along with the following species--one of the most invasive of all the succulent species easily acquired in cultivation. I personally find this one much less annoying as it takes up a lot less space and is marginally easier to eradicate if need be. However, it spreads quickly and efficiently thanks to lots of itty, bitty leaflets that form along the ornamental tubular leaves. Cold kills this species well so those growing where it freezes have little to worry about these problems when planting this one outdoors. This is one of the most heat- and sun-tolerant of the smooth-leaved Kalanchoes and I have yet to see it suffer much in my climate in summers.
Blooming Kalanchoe delagoensis (left); close up showing tubular leaves tipped with leaflets (middle- photo trois) and plants showing up in an arid garden that gets NO water other than rain 4 months out of the year (right or bottom)
unplanted (at least not on purpose) seedlings showing up all over (photo on right by cactus_lover)
Kalanchoe diagremontiana, aka Mother of Thousands, is probably the most infamous of the Kalanchoes and the one that sometimes gives Kalanchoes a bad name, in terms of invasiveness. There are few more invasive succulents than this one, with virtually every inch of this plant having the potential to grow into another plant. It is not uncommon for succulents to be able to be propagated from leaves, flower stalks or root stock, but this plant does it with such ease and ‘enthusiasm' that is a bit frightening. However, the most impressive reproductive strategy this plant uses is the creating and easily dropping of hundreds, if not many hundreds of itty, bitty leaflets that form along the mature leaf margins. That plant itself is somewhat ornamental with large, smooth jagged-edged, variegated leaves and large, bright salmon inflorescences made up of many dozens of flowers. If left to seed, many flower stalks will also form bulbils as if this plant didn't already have enough ways to propagate itself. This plant is sensitive to cold so planting it out in areas that see yearly freezes is relatively safe. It is a vigorous indoor plant and no matter how hard you try, it will often end up showing up in other potted plants throughout the home, and especially if allowed into a greenhouse.
Kalanchoe diagremotaniana photos showing leaflets and seedlings (photo left by LilMissChz, middle by Todd_Boland)
Flowers of Kalanchoe diagremontiana (photo KactusKathi) on left; flower close up (middle); and maturing inflorescence showing bulbil formation and yet another way to spread itself about (right or bottom)
The hybrid 'Pink Butterflies' (there are some other names, too) is a very ornamental form of this species that has lost the ability to produce viable bulbils or leaflets (I assume this was purposely bred out of this plant) and is a much safer plant to put out in the garden. However, it has the downside of being somewhat monocarpic, and usually only lasts a few years until it flowers (at least that's all mine lasted for).
my own hybrid plant showing sterile plantlets on the leaves
Kalanchoe luciae, aka Flapjack Plant or Paddle Plant, is one of the more popular Kalanchoe species in cultivation. More often than not, this species is offered as Kalanchoe thyrisflora which is actually a much rarer but somewhat similar species. Kalanchoe luciae can be told apart by having large, flat and often red-tinged leaves (that look like paddles) while Kalanchoe thyrsiflora is a sea-green plant with smaller, slightly cupped leaves that rarely show any red or pink coloration. Flowers of Kalanchoe thyrsiflora are dark yellow and fragrant while Kalanchoe luciae has pale yellow to nearly white flowers (and supposedly without much of a smell). This plant has little cold tolerance but is one of the more sun-tolerant of the smooth-leaved Kalanchoes only suffering on the hottest days in full sun here in Southern California. This is a monocarpic plant, meaning it will die after flowering. Fortunately it often offsets before actually dying and these offsets can regrow taking the place of the original plant. Plants grown in shade will usually remain a light green while those in full sun or exposed to drought and/or cold will show a variety of color changes including reds, oranges, pinks and even yellows sometimes. This species seems quite prone to mealy bug and snails if grown in moist, shady conditions, and it can rot if overwatered when it's really hot out (seems to go dormant in super hot weather).
See this link for a brief comparison of these two species:
Kalanchoe luciae photos (my own left); young plants for sale at a nursery (middle); happy plants in Florida showing they can take a lot of humidity (right or bottom)
plants starting to flower (left); flower detail (middle) and my plant after flowering showing suckers all around the base (right or bottom)
Unlike the photo at the very top of the article, these plants are true variegated Kalanchoe luciaes (also always misidentified as Kalanchoe thyrsifloras)
The real Kalanchoe thyrsiflora according to Huntington Gardens
Kalanchoe marmorata, aka Penwiper Plant, is another commonly grown and more ‘typical' Kalanchoe. The plant grows as a small shrub of flat, ovoid smooth leaves with most forms having spots and rounded teeth along the distal edges. Many species of Kalanchoe looks similar to this one. This is a species I have seen growing in Florida and Hawaii, obviously tolerating the extreme humidity we do not have here in California. It is not frost tolerant, but seems to come back after frost damage occurs.
Kalanchoe marmorata (two typical forms, and atypical form on right or bottom)
A field grown mass of plants showing some naturally occuring mutations of variegation at the Huntington Gardens
Kalanchoe rhombopilosa is a relatively uncommon species in cultivation, but I mention it for two reasons. One, it is often confused with a much more common species of Adromischus called Bear Paws since it has leaves of a very similar shape. Also a new cultivar (or at least new to me) is showing up in cultivation with extremely ornamental flecking on the leaves. This is a tougher than average plant to grow as it really dislikes heat or cold, preferring to live in a narrow temperature range with little hot, direct sunlight.
Kalanchoe rhombopilosa photos (typical forms on left and middle, photo left Happenstance, and right, or bottom, the newer speckled form)
Adromischus crispa (left) and Crassula tomentosa (right), both more common plants, often confused with Kalanchoe rhombopilosa
Kalanchoe synsepala, aka Walking Kalanchoe, is an interesting species that is mildly invasive and not terribly ornamental, but fun to grow in pots. This plant has large, smooth leaves that can have jagged edges in some cultivars. After flowering, the flower stalk tends to form one large bulbil which ends up weighing the flower stalk down to ground level and there it grows into a new plant (hence the name ‘walking Kalanchoe').
Kalanchoe synespala in pot and garden
Kalanchoe tomentosa, or Panda Plant or Pussy Ears, is a popular species with very fuzzy, soft, ovoid leaves. This plant is probably one of the easiest Kalanchoes to grow (aside from the super invaders described above) both indoors and out, being quite resistant to rot, bugs and tolerant of at least some direct sun. I also have not had much cold damage to this plant despite a freeze nearly wiping out all my other Kalanchoes a few years back. Some cultivars have extra fuzziness while others have various metallic colors. Kalanchoe eriophylla is extremely similar but a tad fussier in my garden.
Kalanchoe tomentosa photos
similar species, Kalanchoe eriophylla
There are many other species of Kalanchoe (see some below) but too many to cover in this introductory article. See the PlantFiles for more on Kalanchoes in cultivation.
Kalanchoe arborescens (looks like an Aeonium sp.) on left; Kalanchoe bracteata forms in middle and right or bottom photos
Kalanchoe crenata (left photo Andrew60); Kalanhoe fedtschenkoi (a relatively common species) in center and right (right or bottom photo RWhiz)
Kalanchoe gastonis-bonnieri in above photos (left photo larryo20)
Kalanchoe humilis (left); Kalanchoe longiflora (center); and Kalanchoe mortagei (right or bottom)
Kalanchoe manginii (left photo by PotEmUp) Kalanchoe orgyalis (right)
photos of Kalanchoe marnieriana (left and middle) in landscape of southern California; Kalanchoe 'Pink Zinfandel' (right or bottom)
Kalanchoe pinnata (another fairly common species) left and center (center photo htop); Kalanchoe tetraphylla (right or bottom)
another fairly common landscape species in my garden (left) and another's: Kalanchoe prolifera (left photo nomosno)
Kalanchoe hildebrandtii in landscape and as a show plant (left and middle); Kalanchoe waldheimii (right or bottom)
There are many more species of Kalanchoe, probably many even in cultivation, but these are the ones you will be most likely to run into.