Kalanchoe is a widely popular flowering houseplant, recognized for its vibrant, clustered blooms and thick, fleshy leaves, categorizing it as a succulent. These plants are frequently purchased while in full flower, often around the winter holidays or in early spring, and are commonly discarded after the blossoms fade. This cycle of seasonal purchase and disposal creates confusion for home gardeners trying to determine if the plant is meant to last for one season or many years. Determining whether this colorful plant is an annual or a perennial requires understanding its native environment and basic botany.
Kalanchoe’s True Life Cycle
A plant classified as an annual completes its entire life cycle within a single growing season, from seed germination to seed dispersal. In contrast, a perennial plant lives for more than two years, often continuing to bloom year after year. Kalanchoe, specifically the common florist’s Kalanchoe (Kalanchoe blossfeldiana), is a perennial succulent. It is native to the tropical island of Madagascar, where it naturally grows as a long-lived, herbaceous perennial. Its thick leaves are an adaptation for water storage, allowing it to endure periods of drought in its native habitat. With appropriate care, these plants can maintain their perennial life cycle and continue growing and reblooming indoors for many years.
The Role of Climate and Hardiness Zones
Despite its perennial nature, Kalanchoe is widely sold and treated as a temporary annual, primarily because of its sensitivity to cold temperatures. As a tropical plant, it cannot tolerate frost and will suffer significant damage or death if exposed to freezing conditions. This low cold tolerance dictates that the plant can only survive outdoors year-round in very specific climates. The USDA Hardiness Zone system outlines the areas where Kalanchoe can function as an outdoor perennial landscape plant. It is reliably hardy only in zones 10 through 12, where temperatures rarely drop below 50 degrees Fahrenheit. In regions with colder winters, which encompasses the majority of temperate North America, the plant must be brought indoors before the first frost. If left outside in these colder climates, the plant will not survive the winter, forcing gardeners to treat it as a temporary seasonal annual.
Maintaining Kalanchoe as a Houseplant
Maintaining Kalanchoe as a perennial means cultivating it exclusively as an indoor houseplant. The requirements for its long-term survival include bright, indirect light, which mimics its natural tropical environment without scorching its foliage. The plant should be potted in a well-draining soil mix, such as a commercial succulent or cactus blend, to prevent water retention.
As a succulent, Kalanchoe stores water in its leaves and is susceptible to root rot if overwatered. Allow the top inch or two of soil to dry out completely between watering sessions. The ideal temperature range for year-round growth is between 60 and 85 degrees Fahrenheit.
To encourage the plant to rebloom, it must be subjected to a specific light cycle, as it is a photoperiodic plant. This process requires giving the plant at least 14 hours of uninterrupted darkness every day for approximately six weeks. This period of extended darkness, combined with a slight reduction in watering, mimics the shorter days of winter and stimulates the formation of new flower buds.