Kalanchoe is a succulent plant that is related to the jade plant. It is often used as a holiday plant because it is easy to trick kalanchoe into blooming in winter, and the blossoms last for weeks. Kalanchoe is winter hardy only in USDA zones 10 to 12 and is grown as a houseplant or in outdoor containers in more temperate climates.
Kalanchoe plants feature large clusters of tightly packed red, pink, salmon, white or yellow flowers that sit above the foliage. The flowers last six to eight weeks with very little care. The lush, succulent foliage is dark green with scalloped edges, and the leaves can grow up to 5 inches in length. The plant grows up to 1 foot 6 inches in height.
Kalanchoe prefers full sun or bright indirect light. Use a potting mixture that drains well and plant in a pot with drainage holes. The plants suffer from stem rot when over-watered, so water thoroughly, then allow the soil to dry before watering again. Use a high phosphorous fertilizer when the plants are actively growing. Baby plants may appear on the margins of the leaves. These plants may be removed and potted.
To encourage a plant to flower, pinch back the stems and place the pot in a place where it will receive 14 hours of darkness per day for at least six weeks. During this time reduce watering and fertilizing, and maintain temperatures of 60 to 70 degrees F.
A Kalanchoe's thick, waxy foliage isn't often bothered by insects, but as with all houseplants, watch for mealybugs, spider mites and scale. Mealybugs look like cotton and sit where the leaf attaches to the stem. They are easy to pick off by hand, or you can dab them with a cotton swab saturated with alcohol. Scale appears as raised brown spots on the leaves. They may can be scraped off. Insecticidal soaps will kill spider mites as well as many other insects that infest houseplants. The spray has to come in direct contact with the insect, so spray all parts of the plant including the undersides of leaves. If a plant becomes seriously infested it should be discarded before the insects spread to other plants.
Growing Kalanchoe Outdoors
In USDA zones 10 to 12 kalanchoe is often grown outdoors. It is used in rock gardens and raised planters, and also makes an ideal ground cover. Kalanchoe needs full sun or partial shade and a light, well-drained, sandy soil. Space the plants six to 12 inches apart. They need only one application of fertilizer each year, preferably in spring.