There are some 125 species of tropical kalanchoe succulents around the world. Different cultivars grow from under 3 feet to 6 feet tall; most of them are perennials or shrubs although a few are annual or biennial. They have evolved in arid climates and so generally need lots of light and should not be overwatered.
Kalanchoe blossfeldiana, originally from Madagascar's dry climate, is the most famous kalanchoe variety and is popular with gardeners because of its rich display of orange, pink, purple and yellow blossoms. The colorful mother of millions, Kalanchoe delagonoensis, also a native of Madagascar, requires care similar to Kalanchoe blossfeldiana.
Kalanchoes needs temperatures between 60 to 85 degrees F in order to bloom. Do not let a kalanchoe sit near drafts or cold windows. A few hours of 40 degree F will kill the plant.
Use small pots for Kalanchoe blossfeldiana or Kalanchoe delagonoensis. Since kalanchoes have sensitive roots that need air, it is better to use clay pots.
The potting compost should contain peat moss, sand and perlite to ensure good drainage. Putting pebbles at the bottom of the pot helps drainage. Drain excess water from the tray.
Add fresh soil when you repot each spring. Do not attempt to grow other plants in the same pot.
Light and Water
Most kalanchoes bloom from to fall to early spring when the days are shorter. Light will encourage growth but reduce blooming. Kalanchoes need some darkness in order to bloom. Keep the light to eight to 10 hours a day to encourage blooming; return to regular lighting after buds have formed.
Kalanchoe roots should not be allowed to sit in water. Water when the top 1 inch of soil is dry when you touch it.
Kalanchoes producing flowers need little fertilizer. To keep a kalanchoe past the first flower, fertilize with 20-8-20 fertilizer once every other week when you see new growth. Apply at 1/4 to 1/2 the rate recommended on the label.
When the flowers begin to die on a kalanchoe, remove them so the plant can rest. After you cut the dying blossoms reduce the water. After the plant has rested it will produce new buds and bloom again.
Pinch the ends of the kalanchoe plant to keep it from getting leggy and to shape it. As the plant gets older, it will get woody.