Sempervivum arachnoideum

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Sempervivum arachnoideum
Sempervivum arachnoideum.jpg
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Saxifragales
Family: Crassulaceae
Genus: Sempervivum
S. arachnoideum
Binomial name
Sempervivum arachnoideum

Sempervivum arachnoideum, the cobweb house-leek,[1] is a species of flowering plant in the family Crassulaceae, native to the Alps, Apennines and Carpathians. Growing to 8 cm (3 in) tall by 30 cm (12 in) wide, it is a rosette-forming succulent perennial, valued in cultivation for its ability to colonise hot, dry areas via offsets.[2]

The specific epithet arachnoideum refers to its furry central rosettes (long ciliate leaf margins), resembling spider webs.[3]

It flowers in July, with pink flowers that are raised on stems and are hermaphroditic (having both male and female organs).

This plant,[4] and the subspecies Sempervivum arachnoideum subsp. tomentosum,[5] have gained the Royal Horticultural Society's Award of Garden Merit.[6]


  1. ^ "BSBI List 2007". Botanical Society of Britain and Ireland. Archived from the original (xls) on 2015-01-25. Retrieved 2014-10-17.
  2. ^ RHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 1405332964.
  3. ^ Harrison, Lorraine (2012). RHS Latin for gardeners. United Kingdom: Mitchell Beazley. p. 224. ISBN 9781845337315.
  4. ^ "RHS Plant Selector - Sempervivum arachnoideum". Retrieved 3 June 2013.
  5. ^ "RHS Plantfinder - Sempervivum arachnoideum subsp. tomentosum". Retrieved 9 November 2018.
  6. ^ "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 96. Retrieved 9 November 2018.