Members of the plant genus sempervivum are also called houseleeks, liveforever or hen and chicks. They are colorful perennial succulents that grow rosettes or fat leaves that store water, enabling them to live in arid conditions. Numerous growers in Europe and North America have developed their own hybrid sempervivums, many of which have found their way on the commercial the market.
Sempervivums are native to a wide range of arid land ranging from northeastern Sahara Desert to the Caucasus area of the Middle East, roughly from Morocco to Iran.
Sempervivums are small succulents with short, thick succulent leaves arranged in a circle. Sempervivums have no stems. The main plant, the hen, sends out new leaves called rosettes, the chicks.
Each chick will produce a star-shaped flower. These flowers are bell-shaped and have six petals. They come in off-shades of green, pink, red, purple, yellow and occasionally white. The plant dies after it flowers, leaving behind offsets that keep growing and reproducing themselves.
Sempervivum are grown for their foliage, not their flowers. The standard foliage, green colored red toward the tip, stays green all winter and is brighter in full sunlight.
Hybrids ordinarily produce different colors of foliage including black, blue, purple, red and other colors.
There are many sempervivum hybrids on the market. Simpervivums are often sold as houseleeks or hen and chicks in American garden-supply centers. When buying hybrids, look for a specific plant names.
Plants are identified according to botanical classes. In descending order plant classes are kingdom, phylum, class, sub-class, order, family, genus and species. In Latin, semper means "forever." Vivum means "to live." The genus name Sempervivum means live forever.
The number of reported sempervivum species varies from 40 to 65. Familiar species include common houseleek (S. tectorum), cobweb houseleek (S. arachoideum) and mountain houseleek (S. montanum).
Hybrids are designated by an x between the specific names of their parents. For example, S. arachnoideum x calcareum designates a hybrid of the species arachnoideum and calcarum in the genus Sempervivum; S. dolomiticum x montanum designates a hybrid of the species dolomiticum and montanum.
The growing behavior of different hybrids are usually the same.
Sun and Soil
Sempervivums like sunlight. They can survive temperatures above 90 degrees and below -5 degrees. They will tolerate humidity when they are growing actively, but the soil should be dry between watering. The humidity should not be high during the winter.
Sempervivums like sandy, well-drained soil. They should be watered only if their soil is totally dry. They should never be allowed to sit in standing water.
Sempervivum are best used to cover rockwork, bare, sandy wastes and dry banks. They are also grown in gardens, flanking sidewalks and lawns and as houseplants.
The popular S. techtorum, usually sold as hen and chicks in the Unites States, is often grown on the roofs of houses in Europe.
S. arachoideum is regarded by many as the most attractive sempervivum.