Kalanchoe blossfeldiana aka Flaming Katy

Kalanchoe blossfeldiana prefers cool-to-average indoor temperatures, roughly 60°F (16°C) at night and 70°F (21°C) during the day. It is frost-intolerant and should be brought indoors or given protection before temperatures drop to about 45°F (7°C); outdoors it is only reliably hardy in USDA zones 10a-12b (RHS H1b, minimum 10-15°C).

Many named cultivars exist, including single-flowered forms like 'Flaming Katy' (bright red), 'Kerinci' (pink), 'Lanin' (orange), and a variegated form (f. variegata) with pink/cream leaf margins, as well as double-flowered types such as 'Queen Jodie', 'Queen Lindsay', 'Simone', and the popular "Calandiva" series.

Kalanchoe blossfeldiana can be grown outdoors year-round only in frost-free climates (USDA zones 10-12), where it works well as groundcover or in rock gardens, raised planters, or containers; it has naturalized in some warm, humid areas such as Florida. Elsewhere it is grown as a houseplant that can be moved outside to a partially shaded spot in summer once frost danger has passed, then brought back indoors before cold weather returns.

Kalanchoe blossfeldiana does not require pruning under normal care.

The plant is propagated easily from stem or leaf cuttings.

Kalanchoe blossfeldiana is naturally a slow-growing plant, so modest growth is normal. If it fails to rebloom, the most common cause is an insufficient dark period — it needs roughly 14 hours of uninterrupted darkness nightly for six or more weeks in fall/winter to reset its flowering cycle.

Common pests include aphids, mealybugs, and spider mites, with occasional vine weevil damage. The main disease risks are root or stem rot from overwatering and powdery mildew, which is best prevented with good air circulation; overall the plant is considered generally disease-resistant.

Kalanchoe blossfeldiana is not edible — every part of the plant (leaves, stems, and flowers) is toxic if ingested by humans or pets. The toxic compounds are cardiac glycosides (bufadienolides), which typically cause vomiting, diarrhea, nausea, and lethargy, and in larger doses can affect heart rate and rhythm.

This species is grown almost exclusively as an ornamental houseplant and container/patio plant; it has no significant food, medicinal, or industrial uses documented. It has received the RHS Award of Garden Merit for its garden and container merit.