Sempervivum is Latin and means "living forever", a fairly true statement in regard to this plant. These members of the Crassulaceae (stonecrop) family happily grow and spread, regardless of drought, hot sun, and even layers of snow, brightening the garden year after year. The only thing they seem to resent is squirrels digging them up! However, even then, the unearthed "hens" and all their little "chicks" can be easily repositioned in the soil and will carry on as though nothing happened.
This hardy perennial grows on the roofs of houses in many parts of Europe, quite possibly the original "green roof!" Historically, this was thought to help ward off storms or witchcraft. The plant's natural habitats are in central and southern Europe and the Mediterranean islands, and they usually are found 3,000 to 8,000 feet above sea level. Over fifty species have been identified, with more than 3,000 named cultivars.
Needing very little water, Sempervivums are perfect for rock gardens and desert-type landscaping; in fact, in too-moist soil, they will rot. They grow in poor soil and do best with lots of full sun; however, they will also grow in shadier spots, but often don't spread as vigorously. The more exotically hued cultivars need lots of sun to maintain their colors, often ranging from green through browns, orange, pink, red, or yellow. Some cultivars have "spiderweb" down covering the leaves.
What is a Succulent?
The Latin word succos means juice or sap, and succulent plants have thick leaves in which they store water, as well as stem and root systems that retain moisture. Examples of succulents include Aloe, Euphorbia, and most cacti.
Sempervivum leaves are thick and fleshy, sharply tipped, and some varieties have downy hairs along the edges (arachnoideum cultivars). Sempervivums are not grown for their flowers, but they do bloom, although the flowers are less than spectacular. The petals are always in multiples of eight, and look like small pink, purple, or sometimes yellow stars. The largest plant in the grouping will grow a long stalk straight out of the center, then the flowers will appear. Once the flowers have finished, the "mother plant" will die back. When this happens, remove the debris and simply fill the empty space with a little gritty medium and add one or two of the smaller offsets growing at the outer edges of the clump.
Sempervivums cooperate nicely with any plans to propagate; each of the smaller rosettes that forms around the perimeter of the main plant is connected by a stolon that will wither once the rosette forms roots. At that time, the rosette can be transplanted and will begin its own cycle of producing more rosettes as it matures. With the right conditions, these colonies of plants grow and spread quite fast during a season.
Pliny the Elder (23 - 79 AD) described a treatment for many skin ailments in Naturalis Historiae; the juice from the crushed leaves of Sempervivum was thought to heal burns, scalds, corns, calluses, warts, ringworm, shingles, insect stings, eye problems, and earache. Discorides (30 - 90 D) also advised the use of the extract for expulsion of intestinal worms and flukes. (I wouldn't recommend trying this.) As an insecticide, the fluid was used by the Romans to eradicate caterpillars in their agricultural fields.
Some Popular Cultivars
- S. arachnoideum 'White Christmas' - pale green with heavy spider-webbing
- S. arachnoideum 'Robin' - spider-webbed with green center and red outer leaves
- Sempervivum 'Bronco' - luminescent purple
- S. calcareum - green center, dark bronze tips and outer leaves
- Sempervivum 'Mrs. Giuseppe' - brilliant green
- Sempervivum 'Lilac Time' - true blue purple with pink edges
- Sempervivum 'Sprite' - tiny, compact, pale green with touches of burgundy
 The Succulent Plant Page
Photo of Sempervivum in rocks used by permission Wikipedia GNU Commons License