Houseleek – Sempervivum Tectorum

Houseleek – Sempervivum Tectorum

Sempervivum (Brit. /sɛmpəˈvvəm/U.S. sem-per-VEE-vum) is a genus of about 40 species of flowering plants in the Crassulaceae family, commonly known as houseleeks. Other common names include liveforever (the source of the taxonomical designation Sempervivum, literally “always/forever alive”) and hen and chicks, a name shared with plants of other genera as well. They are succulent perennials forming mats composed of tufted leaves in rosettes. In favourable conditions they spread rapidly via offsets, and several species are valued in cultivation as groundcover for dry, sunny locations.

The name Sempervivum has its origin in the Latin semper (“always”) and vivus (“living”), because this perennial plant keeps its leaves in winter and is very resistant to difficult conditions of growth. The common name “houseleek” is believed to stem from the traditional practice of growing plants on the roofs of houses to ward off fire and lightning strikes. Some Welsh people still hold the old folk belief that having it grow on the roof of the house ensures the health and prosperity of those who live there.  The plant is not closely related to the true leek, which belongs to the onion family.

Other common names reflect the plant’s ancient association with Thor, the Norse god of thunder, and the Roman Jupiter. Hence names such as “Jupiter’s beard” and the German Donnerbart (“thunder beard”).

Sempervivum Tectorum  has grey-green, tufted, sessile leaves, 4–10 cm (2–4 in) in diameter, which are often suffused with rose-red. In summer it bears clusters of reddish-purple flowers, in multiples of 8-16, on hairy erect flat-topped stems.  The species is highly variable, in part because hundreds of cultivars have been propagated, sold, and traded for nearly 200 years.

Sempervivum tectorum (common houseleek) is a species of flowering plant in the family Crassulaceae, native to the mountains of southern Europe, cultivated in the whole of Europe for its appearance and a Roman tradition claiming that it protects buildings against lightning strikes.Sempervivum tectorum was described in 1753 by Linnaeus, who noted that its leaves are ciliate, that is, fringed with hairs.


This plant has been known to humans for thousands of years, and has attracted many common names and traditions. In addition to common houseleek, names include variations of the following:-

  • bullock’s beard
  • devil’s beard
  • earwort
  • fuet
  • healing blade
  • homewort
  • imbroke
  • Jove’s beard
  • Jupiter’s eye
  • poor Jan’s leaf
  • red-leaved houseleek
  • roof foil
  • roof houseleek
  • St. George’s Beard
  • St. Patrick’s cabbage
  • sengreen
  • Thor’s beard
  • thunderplant
  • Welcome-home-husband-though-never-so-drunk—a name it sometimes shares with Sedum acre.
  • hen and chicks – a name shared with several other plants

The specific epithet tectorum means “of house roofs”, referring to a traditional location for these plants.

Date Planted


Purchase Info

June 14 2017



Diseases and Problems


Folklore and herbalism

The plant has been traditionally thought to protect against thunderstorms, and grown on house roofs for that reason, which is why it is called House Leek.  Many of its popular names in different languages reflect an association with the Roman thunder-god Jupiter, notably the Latin barba Jovis (Jupiter’s beard), referred to in the Floridus traditionally attributed to Aemilius Macer, and its French derivative joubarbe, which has in turn given rise to jubard and jo-barb in English; or with the Norse thunder-god Thor as in German Donnerbart.  It is also called simply thunder-plantAnglo-Saxon þunorwyrtmay have either meaning. However, the association with Jupiter has also been derived from a resemblance between the flowers and the god’s beard; in modern times, it has also been called St. George’s beard. 

Other common names, such as Anglo-Saxon singrēne, Modern English sigrim, sil-green, etc. and aye-green refer to its longevity. William Fernie tells a tale in support of this:

History relates that a botanist tried hard for eighteen months to dry a plant of the House Leek for his herbarium, but failed in this object. He afterwards restored it to its first site when it grew again as if nothing had interfered with its ordinary life. 

It has been believed to protect more generally against decay and against witchcraft.  Jacob Grimm quotes a Provençal troubadour: “e daquel erba tenon pro li vilan sobra lur maiso” — “and that plant they keep against evil atop their house.” In his Capitulare de villis vel curtis imperii, Charlemagne recommended it be grown on top of houses.  In some places, S. tectorum is still traditionally grown on the roofs of houses. 

The juice has been used in herbal medicine as an astringent and treatment for skin and eye diseases, including by Galen and Dioscorides, to ease inflammation and, mixed with honey, to treat thrush; however, large doses have an emetic effect. Pliny also mentions it, and Marcellus Empiricus listed it as a component in external treatments for contusions, nervous disorders, intestinal problems and abdominal pain, and mixed with honey, as part of the antidotum Hadriani (Hadrian’s antidote), a broad-spectrum palliative for internal complaints. 

Romans grew the plant in containers in front of windows and associated it with love medicine. 

Medicinal use

It has been used historically and is used presently as a medicinal herb. It has no known side effects (aside from being an emetic in large doses) or drug interactions. Common herbal uses are stopping bad cases of diarrhea by drinking the juice of the leaf or eating the leaves directly, and the juice is commonly applied directly to the skin for many of the same uses as aloe vera such as burns, warts and insect bites.

The famous English herbalist Culpepper says ‘Our ordinary Houseleek is good for all inward heats, as well as outward, and in the eyes or other parts of the body: a posset made of the juice is singularly good in all hot agues, for it cooleth and tempereth the blood and spirits and quencheth the thirst; and is also good to stay all defluction or sharp and salt rheums in the eyes, the juice being dropped into them. If the juice be dropped into the ears, it easeth pain…. It cooleth and restraineth all hot inflammations St. Anthony’s fire (Erysipelas), scaldings and burnings, the shingles, fretting ulcers, ringworms and the like; and much easeth the pain and the gout.’


Growing to 15 cm (6 in) tall by 50 cm (20 in) broad, it is a rosette-forming succulent evergreen perennial, spreading by offsets.

Houseleeks grow as tufts of perennial but monocarpic rosettes. Each rosette propagates asexually by lateral rosettes (offsets, “hen and chicks”), by splitting of the rosette (only Jovibarba heuffelii) or sexually by tiny seeds.

Typically, each plant grows for several years before flowering. Their hermaphrodite flowers have first a male stage. Then the stamens curve themselves and spread away from the carpels at the center of the flower, so self-pollination is rather difficult. The colour of the flowers is reddish, yellowish, pinkish, or—seldom—whitish. In Sempervivum, the flowers are actinomorphic (like a star) and have more than six petals, while in Jovibarba, the flowers are campanulate (bell-shaped) and are pale green-yellow with six petals. After flowering, the plant dies, usually leaving many offsets it has produced during its life.