Kalanchoe blossfeldiana
| Light | Bright, indirect light indoors; some direct sun outdoors with protection from harsh midday sun |
|---|---|
| Water | When the top few centimetres of soil have dried; ease off in winter |
| Soil | Free-draining succulent or cactus mix (see Soil and potting mix) |
| Temperature | Keep above about 10 °C; frost-tender, USDA zones 10–11 |
| Propagation | Stem and leaf cuttings; also seed |
| Toxicity | Toxic to cats and dogs if eaten (contains bufadienolide compounds) |
Kalanchoe blossfeldiana is a compact, bushy succulent in the family Crassulaceae, and by far the most widely sold flowering member of the genus Kalanchoe. It is the plant most people picture when they hear the name — a tidy mound of glossy, scallop-edged leaves topped by dense, long-lasting clusters of small four-petalled flowers in shades of red, orange, pink, yellow, salmon and white. Sold by the million as a gift and windowsill plant, it is commonly known as Flaming Katy and florist kalanchoe.
Description
Kalanchoe blossfeldiana forms a rounded, shrubby plant usually 20–40 cm tall, with thick, fleshy stems that become somewhat woody with age. The leaves are the classic kalanchoe type: broad, oval, deep green and glossy, with a firm succulent texture and shallowly scalloped or toothed margins that often flush red in bright light.
The flowers are the main event. Each is small, tubular at the base and opening into four spreading petals, and they are carried in crowded, flat-topped clusters well above the foliage. Colour ranges across the warm spectrum and includes many bred doubles with extra petals. A healthy plant can stay in bloom for many weeks, which is a large part of its commercial appeal. Flowering is triggered by short days, so the natural season is late winter into spring, though nurseries force plants into bloom year-round by controlling day length.
Distribution and habitat
The species is native to Madagascar, where it grows on rocky ground in a warm, seasonally dry climate. Like most Malagasy kalanchoes it is adapted to bright light and periods of drought, storing water in its fleshy leaves and stems. Almost every plant seen in cultivation, however, is a nursery-raised hybrid or selection rather than the wild form; intensive breeding has expanded the flower colours, doubled the petals and produced the compact, floriferous habit sold today.
Cultivation
Kalanchoe blossfeldiana is one of the easiest flowering succulents to grow and forgives a good deal of neglect, but it dislikes cold and wet. Give it bright light — a sunny windowsill indoors, or a spot with some protection from the fiercest afternoon sun outdoors — as too little light leads to soft, stretched growth and few flowers. Plant it in a free-draining succulent mix and water only when the top few centimetres have dried, tipping away any water left standing in the saucer. Reduce watering in winter. See Watering and Repotting for general technique.
It is frost-tender and should be kept above roughly 10 °C; in cold climates it is grown as a houseplant or a summer container plant brought indoors before the first frost. A light feed with a balanced or bloom fertiliser during the growing season keeps it vigorous.
Many owners treat it as a temporary "throwaway" plant and discard it after flowering, but it is easy to keep for years. To rebloom it, give the plant a spell of long nights — around six weeks of roughly 14 hours of complete darkness each night — which sets flower buds; trim back the spent flower stalks afterwards to keep the plant bushy.
Propagation
Propagation is straightforward and usually done from cuttings. Take a healthy stem tip or an individual leaf, let the cut surface dry and callus for a day or two, then set it on or in a barely moist, gritty mix; roots and new shoots form readily in warmth. This is the reliable way to keep a favourite colour, since seed-grown plants may vary. See Propagation — cuttings for a full walkthrough. The species can also be raised from its fine seed, which is mainly of interest to breeders.
Common problems
- Rot — the commonest killer, caused by overwatering or a slow-draining mix; stems and leaves turn soft, translucent and brown from the base.
- Etiolation — too little light makes the plant leggy and pale with long gaps between leaves and disappointing flowering.
- No reblooming — a plant kept in bright artificial light every evening never gets the long nights it needs to set buds; give it a period of uninterrupted darkness.
- Pests — mealybugs (white fluff in the leaf axils), aphids on the flower buds, and occasionally spider mites. See Pests and diseases.
Toxicity
Like other kalanchoes, K. blossfeldiana contains bufadienolide compounds and is considered toxic to cats, dogs and other pets if the leaves or flowers are eaten. Keep it out of reach of animals and curious children, and wash your hands after handling if you are sensitive to plant sap.
See also
- Kalanchoe — the genus overview
- Propagation — cuttings · Soil and potting mix · Watering · Repotting · Pests and diseases