''Sempervivum'' (Brit. , U.S.
©sɛ̃mpeɹ'vivÅ©m is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of about 40
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
flowering plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
s in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Crassulaceae
The Crassulaceae (from Latin ''crassus'', thick), also known as the stonecrop family or the orpine family, are a diverse family of dicotyledon flowering plants characterized by succulent leaves and a unique form of photosynthesis, known as Crass ...
, commonly known as houseleeks. Other common names include liveforever (the source of the taxonomical designation ''Sempervivum'', literally "always/forever alive") and
hen and chicks
Hen and chicks (also known as hen-and-chickens, or hen-widdies in the southern United States) is a common name for a group of small succulent plants, a term that indicates a plant that possesses enlarged parts to store water. It belongs to t ...
, a name shared with plants of other
genera as well. They are
succulent perennial
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...
s 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.
Habitat
Houseleeks exist from Morocco to Iran, through the mountains of Iberia, the Alps, Carpathians, Balkan mountains, Turkey, the Armenian mountains, in the northeastern part of the Sahara Desert, and the Caucasus. Their ability to store water in their thick leaves allows them to
live on sunny rocks and stony places in the mountain, subalpine and alpine belts. Most are hardy to US zone 4, and will handle warm climates to about zone 9.
Subtropical origin
Morphologically, they are similar to the genera ''
Jovibarba
''Jovibarba'' ("beard of Jupiter") is a small genus of three species of succulent flowering plants in the family Crassulaceae, endemic to mountainous regions in the southeastern quadrant of Europe. The genus is sometimes classified as a subgenu ...
'', ''
Aeonium
''Aeonium'', the tree houseleeks, is a genus of about 35 species of succulent, subtropical plants of the family Crassulaceae. Many species are popular in horticulture. The genus name comes from the ancient Greek αἰώνιος / aiÅnios (agel ...
'', ''
Greenovia
''Aeonium'', the tree houseleeks, is a genus of about 35 species of succulent, subtropics, subtropical plants of the family (biology), family Crassulaceae. Many species are popular in horticulture. The genus name comes from the ancient Greek αἠ...
'', ''
Aichryson
''Aichryson'' is a genus of about 15 species of succulent, subtropical plants, mostly native to the Canary Islands, with a few in the Azores, Madeira and Morocco.
The species of ''Aichryson'' are not frost-resistant. They are related to ''Semp ...
'', and ''
Monanthes
''Monanthes'' is a genus of small, succulent, subtropical plants of the family Crassulaceae. The about ten species are mostly endemic to the Canary Islands and Savage Islands, with some found on Madeira. Its center of diversity is Tenerife, with ...
'', occurring mainly in Macaronesia (Azores, Canary Islands, Cape Verde, Madeira). Some botanists include some or all of these genera within a wider interpretation of ''Sempervivum'', particularly ''
Jovibarba
''Jovibarba'' ("beard of Jupiter") is a small genus of three species of succulent flowering plants in the family Crassulaceae, endemic to mountainous regions in the southeastern quadrant of Europe. The genus is sometimes classified as a subgenu ...
''.
Origin of name
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" comes from the Anglo Saxon word “leacâ€, meaning plant, since these are literally plants that grow on houses. They were believed to ward off fire and lightning strikes. Some
Welsh
Welsh may refer to:
Related to Wales
* Welsh, referring or related to Wales
* Welsh language, a Brittonic Celtic language spoken in Wales
* Welsh people
People
* Welsh (surname)
* Sometimes used as a synonym for the ancient Britons (Celtic peop ...
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 ''
Allium
''Allium'' is a genus of monocotyledonous flowering plants that includes hundreds of species, including the cultivated onion, garlic, scallion, shallot, leek, and chives. The generic name ''Allium'' is the Latin word for garlic,Gledhill, D ...
'' genus.
Other common names reflect the plant's ancient association with
Thor
Thor (; from non, Þórr ) is a prominent god in Germanic paganism. In Norse mythology, he is a hammer-wielding god associated with lightning, thunder, storms, sacred groves and trees, strength, the protection of humankind, hallowing, an ...
, the Norse god of thunder, and the Roman
Jupiter
Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...
, hence names such as "Jupiter's beard" and the German ''Donnerbart'' ("thunder beard").
Growth and reproduction
![Sempervivum 201806](https://upload.wikimedia.org/wikipedia/commons/0/0d/Sempervivum_201806.jpg)
Houseleeks grow as tufts of
perennial
A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...
but
monocarpic
Monocarpic plants are those that flower and set seeds only once, and then die.
The term is derived from Greek (''mono'', "single" + ''karpos'', "fruit" or "grain"), and was first used by Alphonse de Candolle. Other terms with the same meaning ar ...
rosettes. Each rosette propagates
asexually by lateral rosettes (offsets, "
hen and chicks
Hen and chicks (also known as hen-and-chickens, or hen-widdies in the southern United States) is a common name for a group of small succulent plants, a term that indicates a plant that possesses enlarged parts to store water. It belongs to t ...
"), by splitting of the rosette (only ''
Jovibarba heuffelii
''Jovibarba heuffelii'', common name hen-and-chickens, as a plant species native to the Balkans and to the Carpathians in Europe but reportedly naturalized in Wisconsin and probably in other parts of North America. It grows on rocky outcrops.
'' ...
'') 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
carpel
Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) '' pistils' ...
s at the center of the flower, so
self-pollination
Self-pollination is a form of pollination in which pollen from the same plant arrives at the stigma of a flower (in flowering plants) or at the ovule (in gymnosperms). There are two types of self-pollination: in autogamy, pollen is transferred ...
is rather difficult. The colour of the flowers is reddish, yellowish, pinkish, or—seldom—whitish. In ''Sempervivum'', the flowers are
actinomorphic
Floral symmetry describes whether, and how, a flower, in particular its perianth, can be divided into two or more identical or mirror-image parts.
Uncommonly, flowers may have no axis of symmetry at all, typically because their parts are spirall ...
(like a star) and have more than six petals, while in ''
Jovibarba
''Jovibarba'' ("beard of Jupiter") is a small genus of three species of succulent flowering plants in the family Crassulaceae, endemic to mountainous regions in the southeastern quadrant of Europe. The genus is sometimes classified as a subgenu ...
'', 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.
Identification
![Sempervivum arachnoideum](https://upload.wikimedia.org/wikipedia/commons/0/0f/Sempervivum_arachnoideum.jpg)
The genus ''Sempervivum'' is usually easy to recognize, although it may sometimes be confused with the genus ''
Echeveria
''Echeveria'' is a large genus of flowering plants in the family Crassulaceae, native to semi-desert areas of Central America, Mexico and northwestern South America.
Description
Plants may be evergreen or deciduous. Flowers on short stalks (cyme ...
''. However, its species are often not easy to identify. Even one single clone can look very different under various growth conditions (
modifications) or different times of the year. The members of this genus are very similar and closely linked to each other. As a consequence, many
subspecies,
varieties
Variety may refer to:
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* Variety (radio)
* Variety show, in theater and television
Films
* ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont
* ''Variety'' (1935 film), ...
, and
form
Form is the shape, visual appearance, or configuration of an object. In a wider sense, the form is the way something happens.
Form also refers to:
*Form (document), a document (printed or electronic) with spaces in which to write or enter data
...
s were described, without well-defined limits between them. As a second consequence, there is a high frequency of natural
hybrids in this genus and the possibility of
back-crossing
Backcrossing is a crossing of a hybrid with one of its parents or an individual genetically similar to its parent, to achieve offspring with a genetic identity closer to that of the parent. It is used in horticulture, animal breeding, and produc ...
s of these. However, more or less 40 species can be individualized in the whole area of the genus, but there are many more local
population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a ...
s, without nomenclatural valour but sometimes with their own characters.
![Sempervivum kosanini 2](https://upload.wikimedia.org/wikipedia/commons/a/a6/Sempervivum_kosanini_2.jpg)
In the Alps, for example, the most distributed species are ''S. tectorum'' (common houseleek, sometimes called ''S. alpinum''), ''S. montanum'' (mountain houseleek) and ''S. arachnoideum'' (cobwebbed houseleek), each one with several subspecies. More local are the yellow-flowered ''S. wulfenii'' and ''S. grandiflorum'', and the beautiful limestone houseleek (''S. calcareum''). More rare are ''S. dolomiticum'' and mainly ''S. pittonii''. ''S. pittonii'' is a small yellow-flowered jewel growing only on two mountains slopes near Kraubath in the Mur valley in Austria and is very threatened.
On roofs or old walls ''S. tectorum'' can be found, more or less wild, very far out of its natural area. It is a very old medicinal and witch-plant. Some
superstitious people believe this plant is able to protect a house from
lightning
Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an avera ...
.
Herbalism
It has been used historically and is used presently for purported health benefits. It has no known side effects (aside from being an
emetic
Vomiting (also known as emesis and throwing up) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose.
Vomiting can be the result of ailments like food poisoning, gastroenteritis ...
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.
It is furthermore said to bring relief in cases of swellings and water retention.
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 deflection 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.'
Garden and container plants
![Sempervivum Pittonii (5796665651)](https://upload.wikimedia.org/wikipedia/commons/4/4e/Sempervivum_Pittonii_%285796665651%29.jpg)
Although their subtropical cousins are very frost-sensitive, sempervivums are among the most frost-resistant succulents, making them popular garden plants. They tend to grow best in dry conditions with well-draining, sandy soil to prevent soggy roots. They require only moderate watering, especially during warmer months, with occasional protection from extreme sun exposure.
Sempervivums also make suitable plants for containers, and do well in breathable terracotta, concrete, and cement pots. They have also been known to
grow in rock crevices, metal containers, succulent wreaths, roof shingles, and anywhere else that allows adequate root drainage.
Cultivars
Collectors are numerous and often have many different
cultivar
A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...
s in their collections. Sempervivums are very variable plants and hence hundreds, maybe thousands of cultivars have been created, but a lot of them are not much different from each other. The main interest of these cultivars is not their flowers, but form and color of the rosette-leaves.
The following species and cultivars - some of mixed or uncertain parentage - have gained the
Royal Horticultural Society
The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity.
The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nor ...
’s
Award of Garden Merit:-
*''Sempervivum arachnoideum''
*''Sempervivum arachnoideum'' subsp. ''tomentosum''
*’Bronco’
*''Sempervivum calcareum'' ‘Extra’
*''Sempervivum calcareum'' ‘Guillaume’
*''Sempervivum ciliosum''
*‘Lilac Time’
*’Othello’
*''Sempervivum pittonii''
*‘Reinhard’
*''Sempervivum tectorum''
Gallery
File:Selection of Sempervivums.JPG, A selection of ''Sempervivum'' cultivars, for sale at Gardeners' World Live 2012
File:My Semp Table (5849671628).jpg, A personal collection of potted sempervivums
File:Sempervivum Pittoni (5849673066).jpg, ''Sempervivum pittoni''
File:Sempervivum tectorum in situ 2.jpg, Sempervivum on a roof
File:Bicknell Sempervivuim June 2020.jpg, Close up of large sempervivum
References
*
External links
{{Taxonbar, from=Q161695
Crassulaceae genera
Succulent plants
Garden plants