While both Echeveria and Sempervivum belong to the Crassulaceae family, they are classified into different genera, indicating a significant genetic divergence. Echeveria is a genus comprising over 150 species, native primarily to the semi-desert regions of Central America, Mexico, and northwestern South America. In contrast, Sempervivum, commonly known as Hens and Chicks, is a genus native to mountainous regions of southern Europe and northern Africa. This fundamental difference in origin and genus means they are not closely related and will not hybridize with each other.
The rosettes of these two genera exhibit distinct characteristics. Echeveria plants typically have thicker, fleshy, and often spoon-shaped or paddle-shaped leaves that feel smooth or powdery due to a protective farina (epicuticular wax). Their leaves are generally more ovate and can display a stunning range of colors from pastel blues and greens to vibrant pinks and purples. Sempervivum rosettes are also fleshy but their leaves are usually thinner, pointier, and often have tiny hair-like cilia along the leaf margins, giving them a slightly fuzzy appearance. The leaf tips of many Sempervivum species may also feature a distinctive dark, reddish-brown point.
Both plants propagate prolifically via offsets (the "chicks"), but the manner in which they do so differs. Sempervivum produces these offsets on above-ground stolons, which are slender stems, creating a tight cluster around the mother plant. Most notably, the mother rosette (the "hen") is monocarpic; it will flower, set seed, and then die after the blooming process. Echeveria, however, produces offsets either on short runners or directly at the base of the plant. Crucially, the mother plant of an Echeveria is polycarpic; it will flower repeatedly year after year and does not die after blooming.
The flowers provide one of the most reliable visual distinctions. Echeveria flowers grow on long, arching stalks (racimes) that emerge from the side of the rosette. The flowers themselves are bell-shaped or urn-shaped, often in shades of pink, orange, or yellow, and remain pendulous. Sempervivum flowers grow on a tall, upright, unbranched stalk that emerges from the very center of the rosette. Their flowers are star-shaped, typically pink or reddish-purple, and face upwards. The death of the monocarpic Sempervivum rosette after flowering is a stark contrast to the continued life of the flowering Echeveria.
This is a critical difference for gardeners. Sempervivum are exceptionally cold-hardy succulents. Many species can survive freezing temperatures far below zero (down to USDA zone 4 or -30°F/-34°C) and are adapted to cold winters through a period of dormancy. Echeveria, hailing from warmer climates, are not frost-tolerant at all. They will suffer damage or die if exposed to freezing temperatures and are typically grown outdoors only in frost-free climates (USDA zones 9 and above). They often experience a summer dormancy period to escape extreme heat.
