Kalanchoe fedtschenkoi, the lavender dancer of the windowsill

Daniel Platteau indoor plant Succulent plant Poisonous plant

Before you even touch one of its leaves, Kalanchoe fedtschenkoi intrigues like a character in a botanical novel: graceful, prolific, colourful, but with a darker side. Behind its blue-green leaves edged with cream and pink, behind its coral bells that open in the depths of winter, lies a succulent of the Crassulaceae family, native to Madagascar and now sold in garden centres all over the world. Its variegated form appeals to lovers of graphic plants, and its ease of propagation delights growers. But it belongs to a genus that is toxic to pets, and some of its cousins have become invasive in warm climates. Here is a full portrait, so you know exactly what you are dealing with before inviting it onto your windowsill.

Botanical portrait

Name, family and classification

Kalanchoe fedtschenkoi belongs to the Crassulaceae, succulent plants with fleshy leaves that save water thanks in particular to CAM metabolism: they open their stomata at night to limit water loss.

The species was long placed in the genus Bryophyllum, which grouped Kalanchoe able to form plantlets on their leaves, before being returned to Kalanchoe. That is why you still find labels in the trade reading "Bryophyllum fedtschenkoi" or "Kalanchoe Bryophyllum 'Variegata'". These names refer to the same plant.

In English it is called "lavender scallops", and "variegated lavender scallops" for the variegated form: an evocative name that describes its scalloped, blue-green leaves washed with mauve. Its epithet honours the Russian botanist Boris Fedtschenko.

The genus Kalanchoe has more than a hundred species, including the famous Kalanchoe blossfeldiana sold as a flowering pot plant. K. fedtschenkoi stands out with its small sub-shrub habit, more graphic look and very fleshy leaves.

Morphology: a small succulent sub-shrub

Kalanchoe fedtschenkoi forms a small sub-shrub about 30 to 50 cm tall, upright at first and then trailing. Its stems, fleshy and slightly woody at the base, bend as they lengthen until they touch the ground, where they can root: a single plant eventually forms a small, dense clump.

The leaves are its main asset. Opposite, fleshy, oval to almost round, they have a clearly scalloped edge, like a row of scallop shells. The variegated form, called 'Variegata' or 'Marginata' and the most common in the trade, has a glaucous blue-green leaf, sometimes tinged with lavender, edged with cream, which becomes streaked with bright pink in good light. As the pale areas contain less chlorophyll, this form is slightly more delicate than the all-green one.

Like its cousins from the former genus Bryophyllum, it can sometimes form small plantlets on the edges of its leaves, especially on a leaf that has fallen to the ground. It is, however, far less prolific than the species nicknamed "mother of thousands" (Kalanchoe daigremontiana, K. × houghtonii).

Flowers: coral bells in winter

The flowers are tubular, hanging like bells, coral to orange-pink, gathered in loose clusters above the foliage. Their four-lobed corolla is typical of the genus.

Flowering takes place in late autumn and winter, as the days shorten: like many Kalanchoe, the plant needs long nights to flower. A plant kept in a room that is lit in the evening often flowers less, or not at all. The contrast between the coral bells and the bluish foliage is very painterly, especially when several plants are grouped together.

Origin and history

Madagascar, the plant's cradle

Kalanchoe fedtschenkoi is native to Madagascar, an island famous for its spectacular endemism. It grows there in open, rocky, well-drained habitats with alternating dry and wet seasons.

Madagascar has given horticulture many ornamental Kalanchoe, starting with K. blossfeldiana. K. fedtschenkoi, long reserved for collectors, has become more popular with the succulent craze since the 2000s. The variegated form, probably from a spontaneous mutation, is propagated by cuttings and now dominates the market.

A plant that can escape from gardens

In warm climates, several Kalanchoe have escaped from gardens to colonise natural habitats. In Florida, the University of Florida (UF/IFAS) records several naturalised species, including Kalanchoe pinnata and Kalanchoe × houghtonii, classed as invasive: they form dense carpets, particularly on coastal dunes, at the expense of native vegetation.

K. fedtschenkoi is not listed among the invasive species, but it shares the genus's ease of vegetative reproduction. In a frost-free climate, it is best kept in pots or in well-defined areas. In a Belgian climate it does not survive outdoors in winter, so the risk does not arise, as long as you don't throw fragments into the wild while travelling somewhere warmer.

Growing and care

Light: bright, with some sun

Light is the deciding factor. Indoors, give it the brightest spot possible: an east-, west- or south-facing window with a few hours of direct sun, ideally in the morning. It is light that brings out the pink and lavender tones of the foliage. Short of light, the plant becomes leggy: long stems, widely spaced leaves and dull colours.

If you put it out on a terrace in summer, acclimatise it gradually to full sun: a plant fresh from a garden centre or a room can scorch within hours. Start in bright shade, then increase exposure over one to two weeks.

Temperature: a chilly customer

Kalanchoe fedtschenkoi cannot tolerate frost. In our climate it is therefore grown as a houseplant, possibly moved to the terrace from late May to late September, and brought back in as soon as nights fall below 7 to 10 °C. It likes temperatures of 15 to 25 °C, and a slightly cooler winter (12 to 15 °C) in a bright room encourages flowering.

In a very mild Mediterranean climate, it can live outdoors all year in very free-draining soil, sheltered from cold winds; a single night of frost can, however, damage it badly.

Growing medium and watering: the art of avoiding rot

Like all succulents, it needs a very free-draining mix: a cactus and succulent compost, or ordinary compost lightened with 50% mineral material (coarse sand, pumice, perlite, fine gravel). The pot must have drainage holes, and the saucer should be emptied after each watering.

Water only when the mix is dry: in practice, every 10 to 15 days in spring and summer, every 3 to 4 weeks in winter. Water thoroughly until water runs out of the bottom, then let it dry out completely. The dry air of flats suits it perfectly: no need to mist it.

Overwatering shows as soft, translucent leaves and stems that blacken or collapse at the base. In that case, the safest course is to take cuttings from the healthy parts and start again in fresh mix.

Feeding

It needs little: a diluted cactus and succulent fertiliser once a month from spring to late summer is enough. Nothing in winter.

Pruning: keeping it compact

Left to its own devices, the plant becomes long and bare at the base. To keep it compact:

• cut off faded flower stems;
• in spring, shorten stems that are too long by about a third, just above a pair of leaves: the plant will branch.

The pieces you cut off make excellent cuttings.

Where to put it?

Indoors, it nicely structures a windowsill or a bright shelf, alone or with other succulents with similar needs: bluish Echeveria, small Sedum, Haworthia… In a succulent bowl, it readily plays the role of the trailing plant that softens the edge.

Propagation: child's play

Stem cuttings, the easiest method

This is the most reliable method:

1. Cut a piece of stem at least 5 to 10 cm long, just below a pair of leaves.
2. Remove the lower leaves.
3. Let the cut dry for a day or two so that it heals over.
4. Plant the cutting in barely moist succulent mix, and water very little for the first few days.

Roots appear within a few weeks. The cutting can also root in a glass of water, changing the water every two or three days, but it will then have to adapt to the mix: rooting in compost is often safer for a succulent.

Leaf cuttings

A cleanly detached leaf, left to dry for a few days and then laid on dry mix, can produce roots and a small rosette. It is slower than stem cuttings, especially for the variegated form.

Trailing stems and division

Stems that touch the soil root by themselves: just cut them off and pot them up. You can also divide a dense clump when repotting, separating stems that have roots.

A single plant can thus become a whole family of pots to give away. Just remember to warn recipients who have pets (see below).

Toxicity: the genus's dark side

Cardiac glycosides

Kalanchoe contain bufadienolides, cardiac glycosides whose action resembles that of digitalis. The ASPCA lists Kalanchoe among plants toxic to dogs and cats. The genus is also responsible for serious, sometimes fatal, poisonings in livestock that eat large quantities of it in regions where it has naturalised.

Symptoms in animals

In pets, ingestion mainly causes digestive upset (vomiting, diarrhoea, drooling) and lethargy. More rarely, after eating a large amount, heart rhythm disturbances can occur.

If your pet eats some, contact your vet immediately. Do not make the animal vomit yourself: it is for the vet to decide on treatment. For a child, call a poison centre (in Belgium: 070 245 245; elsewhere, your local poison control centre).

Living with pets

• Keep the plant out of reach of dogs and cats: a high shelf, a room they don't go into.
• Birds flying free in the house are also at risk.
• Pick up fallen leaves.
• If you give a cutting away, mention its toxicity to people who have pets.

No medicinal or food use

Some Kalanchoe, notably K. pinnata, are used in traditional medicine, but no such use is documented for K. fedtschenkoi. The margin between effect and toxicity of cardiac glycosides is narrow: never eat this plant and do not use it for self-medication. It is a purely ornamental plant.

Pests and diseases

Mealybugs and red spider mites

Mealybugs form white, cottony clusters in the leaf axils and on the stems. Remove them with a cotton bud soaked in 70% alcohol, then keep an eye on the plant for a few weeks. Red spider mites cause pale speckling and fine webs, in warm, dry air.

Check the leaf axils and the undersides of the leaves regularly. A well-lit, correctly watered plant resists much better.

Root rot

This is the main cause of death: a plant that seemed healthy suddenly collapses, with soft leaves and a brown, soft stem base. The cause is almost always a mix that is too wet or too heavy. Prevention: very free-draining mix, letting it dry out completely between waterings, no water in the saucer. If it strikes, save healthy cuttings.

Varieties and place in the trade

You will mainly find two forms:

• the species form, with blue-green foliage washed with mauve;
• the variegated 'Variegata' (or 'Marginata'), edged with cream and pink, the most sought-after.

It is usually sold in small pots at a modest price, in garden centres, from succulent specialists or online. For growers it is an interesting plant: easy propagation, good shelf life, and winter flowering that lets it be promoted in a quiet season. A clear note of its toxicity to pets on the label is a sign of a serious grower.

Conclusion: an attractive plant, to be adopted knowingly

Kalanchoe fedtschenkoi has everything going for it: scalloped blue-green leaves edged with cream and pink, coral bells in midwinter, easy care as long as it gets light and free-draining soil, and cuttings anyone can take. It is perfectly suited to our dry interiors and to people who don't have time to pamper their plants.

It does, however, call for a little awareness: it is toxic to dogs, cats and birds, and in warm climates its cousins have shown that a Kalanchoe can become invasive. Kept out of pets' reach and grown in a pot, it remains a pure pleasure.

And you — where will you put it so that its colourful dance stays risk-free, for your pets and for the environment?

Sources

• Kew, Plants of the World Online: taxonomy and native range of Kalanchoe fedtschenkoi.
• ASPCA – Kalanchoe: toxicity to dogs and cats.
• UF/IFAS Extension (University of Florida): naturalised and invasive Kalanchoe in Florida.
• Royal Horticultural Society: growing Kalanchoe and indoor succulents.
• Belgian Poison Centre: what to do if a plant is swallowed.