The Kalanchoe is a genus of flowering succulent plants, comprising over 125 accepted species. As a member of the stonecrop family, Crassulaceae, these plants are popular for their long-lasting, vibrant flowers and fleshy foliage. They are widely cultivated as low-maintenance houseplants, especially the common Florist Kalanchoe.
Botanical Identity and Classification
The Kalanchoe genus is classified within the plant family Crassulaceae. While a few species are found in Asia and the Americas, the majority are native to the Old World, with a significant concentration in Madagascar and tropical Africa.
A defining feature of Kalanchoe is its use of Crassulacean Acid Metabolism (CAM) photosynthesis. This metabolic pathway allows the plant to open its stomata—the pores on its leaves—only at night to absorb carbon dioxide. By keeping the stomata closed during the hot, dry day, the plant significantly reduces water loss through transpiration. This water-conserving strategy makes Kalanchoe species exceptionally drought-tolerant.
Essential Care Requirements
To keep a Kalanchoe healthy, providing the correct balance of light and water is necessary, as they are sensitive to overwatering. They require bright, indirect sunlight for optimal growth and flowering, often thriving near a south- or west-facing window indoors. While they can tolerate some direct morning sun, harsh afternoon light can scorch the leaves.
The plant’s succulent nature means watering needs are minimal; the soil must dry out completely between waterings. Overwatering is the most common cause of plant failure, leading to root rot. A well-draining soil mixture, such as a commercial cactus or succulent mix, is necessary to prevent waterlogged conditions.
Kalanchoe plants prefer warm indoor temperatures, thriving between 55°F and 85°F. Protect them from cold drafts and temperatures below 50°F, which can cause damage. Fertilizing should be done sparingly, typically once a month during the active growing seasons of spring and summer.
Popular Varieties and Appearance
One of the most commonly encountered types is Kalanchoe blossfeldiana, often sold as the Florist Kalanchoe or Flaming Katy.
Kalanchoe blossfeldiana (Florist Kalanchoe)
This variety is prized for its dense clusters of small, four-petaled flowers that bloom in vibrant shades of red, orange, yellow, and pink. It typically has glossy, dark green, scallop-edged leaves that contrast with the colorful flower heads.
Kalanchoe daigremontiana (Mother of Thousands)
This plant is identified by its unique reproductive method, where tiny plantlets form along the scalloped margins of its long, fleshy leaves. These miniature versions drop off and root readily, allowing the species to spread prolifically.
Kalanchoe luciae (Paddle Plant)
The Paddle Plant is grown primarily for its foliage rather than its bloom. It features large, flat, rounded leaves that stack on top of one another, resembling paddles or flapjacks. When exposed to bright light, the edges of the pale green leaves develop a reddish or magenta coloration.
Safety Concerns
All Kalanchoe species are considered toxic if ingested, particularly to household pets like cats and dogs. The plants contain potent compounds called bufadienolides, a type of cardiac glycoside. These toxins can affect both the gastrointestinal system and the heart.
Initial symptoms of ingestion often include vomiting and diarrhea. Ingesting larger quantities, especially the flowers which have a higher concentration of toxins, can lead to more serious issues. Severe symptoms may include lethargy, weakness, abnormal heart rate or rhythm, and in rare cases, seizures or collapse. Pet owners should place Kalanchoe plants out of reach of curious animals.