Sempervivum arachnoideum (Cobweb Houseleek)

Sempervivum arachnoideum on 6-1-14, #228-75.

Cobweb Houseleek

Sempervivum arachnoideum ‘Cebenese’

sem-per-VEE-vum  a-rak-NOY-dee-um

ROYAL HORTICULTURAL SOCIETY AWARD OF GARDEN MERIT

Synonyms of Sedum arachnoideum (7) (Updated on 2-21-21): Sedum arachnoideum E.H.L.Krause, Sempervivum × barbulatum subsp. etruscum D.Donati & G.Dumont, Sempervivum doellianum C.B.Lehm., Sempervivum hausmannii Nyman, Sempervivum heterotrichum Schott, Sempervivum moggridgei De Smet ex Hook.f., Sempervivum sanguineum Jeanb. ex Timb.-Lagr.

Sempervivum arachnoideum L. is the correct and accepted scientific name for this species of Sempervivum. The genus and species were named and described as such by Carl von Linnaeus in the first volume of the first edition of Species Plantarum in 1753. I am not sure if he was actually the first to name either one, though… 

As of 11-19-21 when this page was last updated, Plants of the World Online by Kew lists 52 species in the Sempervivum genus. it is a member of the plant family Crassulaceae with 36 genera. Those numbers could change as updates are made on POWO.

THERE ARE A FEW LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING.

Sempervivum arachnoideum on 6-29-14, #230-79.

Sempervivum arachnoideum is native to the Pyrenees, Alps, Apennines, and Carpathian mountains in Europe. The species is quite variable, including dwarf and crested forms, which all hybridize easily.

Sempervivum arachnoideum on 7-12-14, #231-82.

The species is unique in that the leaf tips are connected with webbing that resembles cobwebs. There are several cultivars available and the degree of webbing varies. There are also red and maroon types.

Sempervivum ‘Cosmic Candy’ on 6-13-19, #588-6..

I brought this Sempervivum ‘Cosmic Candy’ home from Wildwood Greenhouse in 2019. Actually, the label said it was ‘Berry Bomb’ which was renamed by Chick Charms. I choose to use the correct name…

Sempervivum ‘Cosmic Candy’ on 6-13-19, #588-7..

A view from the top of Sempervivum ‘Cosmic Candy’.

Sempervivum arachnoideum on 4-3-21, #788-12.

Wagler’s Green had several to choose from in 2021, so I brought home another one…

Sempervivum arachnoideum on 4-3-21, #788-13.

What can I say? Maybe they don’t overwinter well here for some reason like the labels and information online suggest but they do make interesting plants over the summer. I always bring them inside for the winter but they “usually” don’t do so well… I will keep bring these plants home because they are interesting…

USEFUL INFORMATION:
Family: Crassulaceae.
Origin: Mountains of Europe.
Zones: USDA Zones 4a-9b (-30 to 25° F).*
Size: 2 1/3 to 4” tall.
Light: Sun to part shade.
Soil: Well-drained.
Water: Average during the growing period, dryer during the winter months.

*Dave’s Garden says down to 3a but that is probably with good protection. Sempervivum can be tricky in some areas. I have tried several and so far only Sempervivum x ‘Killer’ has done well overwintering outside. Sempervivum  ‘Oddity’ has done well overwintering in the basement over the winter but eventually bit the dust. I tried a few more times. I have had six different Sempervivum cultivars since 2013…

Flowers of this species are normally pink, but there are also white and red variations. Flowers are held above the leaves on a 6-7” stems. Once the plant flowers and sets seed it will die. Hopefully there will be plenty offsets.

There are many Sempervivum species that tolerate cold better than others. They particularly dislike cold, wet winters and that is somewhat difficult to remedy in some areas. The webbing of this particular species will catch and hold water which could make rotting an issue. 

Sempervivum are easy to grow in elevated beds and pots which allows water to drain much better. Sunny spots are favored but in hot climates they may need a shadier spot because they are not that heat tolerant. 

I am not sure what did my Sempervivum arachnoideum in, but I think I tried to overwinter it in a pot inside and others in the ground. Either way, neither attempt was successful. Maybe someday I will run across another pot and give them another shot. How has your experience been with this species?

I hope you enjoyed this page and maybe found it useful. If you have any comments, questions or suggestions, I would like to hear from you. Please click on “like” if you visited this page. It helps us bloggers stay motivated. 🙂 You can check out the links below for further reading. The links take you directly to the genus and species of this plant.

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
LLIFLE (ENCYCLOPEDIA OF LIVING FORMS)
DAVE’S GARDEN
THE NATIONAL GARDENING ASSOCIATION
ROYAL HORTICULTURAL SOCIETY
SUCCULENTGUIDE
INTERNATIONAL CRASSULACEAE NETWORK

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