Kalanchoe, A Colorful Holiday Succulent

by Nancy Miller, Fairfax Master Gardener

Kalanchoes

Kalanchoes

Kalanchoes are popular, easy to grow houseplants that are prized for their long-lasting colorful flowers and attractive succulent foliage. They are available in vibrant red, orange, yellow, pink or white, as single blooms or in clusters. Some species can even reproduce from buds that form plantlets at the leaf edges. Kalanchoes are frequently used as ornamentals in rock gardens, as container plants and as houseplants.

Kalanchoe (ka-lan-KOH-ee) is a genus of tropical, perennial succulents native to Africa (Madagascar), Asia and South America. It is a member of the stonecrop family, Crassulaceae (jade plant) and has 174 accepted species. Some common names include Chandelier Plant, Devils Backbone, Mother-in-Law Plant, Mother of Millions and Mother of Thousands. The genus has been previously known as Bryophyllum or Vereia.

Kalanchoe is derived from the Chinese words Kalan chau, meaning “that which falls and grows.” This refers to species like K. daigremontiana that have leaves that produce plantlets that drop off and produce new plants. The name was first used by French botanist Michael Adamsen in 1763. The plant was introduced to Europe about 1930 by Robert Blossfeld, a German plant breeder from Potsdam. His original red introduction became popular and during the 1960’s and 1970’s, breeders developed a wide array of colors in hybrids. A chance find in a Swedish nursey in 2002 lead to a new series, marketed as Calandiva. These hybrids have 32 petals arranged in tight rosettes (like miniature roses) rather than the species’ four petals. Calandiva is available in all the colors found in the species.

In temperate climates, Kalanchoes prefer interior sites with bright indirect sunlight, dry soil and low relative humidity. They tend to become spindly if the light is too low. Plants are winter hardy in Zones 9 to 12. They prefer temperatures between 60 and 85 F (15 and 30º C)and can be planted in containers and brought indoors before temperatures drop below 50 F (10º C). Frequently they are grown as a specialty succulent for temporary vibrant color. Once established, they are drought tolerant and may be propagated by division, offsets or stem or leaf cuttings. Outside, plants attract bees and butterflies and are resistant to deer, drought and rabbits.

Kalanchoe grown indoors

Kalanchoe grown indoors

Kalanchoes are short-day plants that bloom naturally in January and February. The leaves are long-petioled, spatulate and fleshy with scalloped margins. Plants are topped by inflorescences of 4-petaled flowers enclosed in a green sheath of sepals at the base. Because the flowering stems progressively open from the center to the outside, plants remain in bloom for six to eight weeks. Blooming is maximized by cooler temperatures and good drainage.

When grown as a houseplant, a kalanchoe prefers a bright indoor location between 50 and 70 F (10 and 21º C) during the day and 45 to 65 F (7 to 18º C) at night. Water well then allow the soil to dry out before watering again. Do not let water to stay in the tray. An optimum soil mix is 60 percent peat moss and 40 percent perlite. Any houseplant fertilizer can be used monthly when the plant is actively growing. Size will depend on the species, but most will range between 6 inches (12 cm) to 2 feet (60 cm) tall and wide. You can choose from a wide variety of species with unusual features in addition to the ones that we know and love that we normally see offered at local retailers.

The problems in growing are minimal: monitor for mealybugs, aphids and brown scale as in any houseplant. Root rot will result from overwatering. If overcrowded, powdery mildew may show up. You should also be aware that plants in this genus are toxic to humans and pets if ingested. Keep them out of reach of curious mouths! Use gloves to prevent contact dermatitis. Knowledgeable ethnobotanists use several species to treat inflammation, wounds, gastric ulcers and other diseases.

K. blossfeldiana, the species most often seen commercially, can be kept after blooming and will rebloom the following year. In October, you will need to completely restrict light to 14-hour nights for six weeks, keeping the temperature to 65 to 70 F (18 to 21º C) during the day and to 60 to 65 F (15 to 18º C) at night. Once flower buds are clearly visible above the foliage, you can return the plant to its normal location. It takes about twelve weeks to flower after the start of long nights, so your plant should be flowering again by January.

K. blossfeldiana

K. blossfeldiana

If you decide to propagate, do it in spring or early summer. Use vegetative shoots (not flowering), 2 inches to 3 inches (5 cm to 7 cm) long with two pairs of leaves. Remove the bottom set of leaves and allow the shoot to callus for several days before potting in well-draining soil. Cover the pot with a plastic bag to maintain high humidity and place it indoors in bright indirect light. Cuttings should be ready to transplant in 14 to 21 days.

If you decide to pursue this genus, you should be aware that (as with any popular, widely distributed plant) several species have escaped cultivation and become invasive in more tropical (Zones 9 to 10) areas. Our Zone 7 should be safe, but with global warming we should be aware of possible potential problems. Never dump cultivated plant material in natural or disturbed areas. Dispose of it securely to prevent future issues.