Wild Wonders of Europe / Benvie / Mountain houseleek (Sempervivum montanum) close-up of two flowers, Fliess, Naturpark Kaunergrat, Tirol, Austria, July 2008 WWE OUTDOOR EXHIBITION.

Wild Wonders of Europe / Benvie / Mountain houseleeks (Sempervivum montanum) in flower, Fliess, Naturpark Kaunergrat, Tirol, Austria, July 2008

Phil Savoie / Hairy yellow-faced Bee (Hylaeus hyalinatus), with raindrop on head, visiting Common Houseleek (Sempervivum tectorum. At 3.5mm average size, this is one of the smallest bees in the UK) Monmouthshire, W...

Edwin Giesbers / Titania's fritillary (Boloria titania) basking on rock with Lichens (Rhizocarpon geographicum) and houseleek plant (Sempervivum arachnoideum) Aosta Valley, Gran Paradiso National Park, Italy.

Edwin Giesbers / Cobweed houseleek (Sempervivum arachnoideum) Aosta Valley, Gran Paradiso National Park, Italy.

Chris Mattison / Houseleek (Sempervivum ciliosum var borisii) in cultivation, origin in Bulgari

Nick Upton / Pale stonecrop (Sedum sediforme) flowering on coastal dunes, Algarve, Portugal, August 2013.

Nick Upton / Pale stonecrop (Sedum sediforme) flowering on coastal dunes, Algarve, Portugal, August 2013.

Nick Upton / Pale stonecrop (Sedum sediforme) flowering on coastal dunes, Algarve, Portugal, August 2013.

Alex Hyde / Mountain Houseleek (Sempervivum montanum) growing amongst rocks on scree slope. Nordtirol, Austrian Alps, June.

Alex Hyde / Hummingbird Hawkmoth (Macroglossum stellatarum) camouflaged on rock with wings closed whilst resting during cloudy weather. A clump of Cobweb Houseleek (Sempervivum arachnoideum) is growing next to it...

Alex Hyde / Cobweb Houseleek (Sempervivum arachnoideum) Nordtirol, Austrian Alps. June.

Alex Hyde / Cobweb Houseleek (Sempervivum arachnoideum) Nordtirol, Austrian Alps. June.

Alex Hyde / Mountain Houseleek (Sempervivum montanum) growing amongst rocks on scree slope. Nordtirol, Austrian Alps, June.

Alex Hyde / Mountain Houseleek (Sempervivum montanum) growing amongst rocks on scree slope. Nordtirol, Austrian Alps, July.

Alex Hyde / Mountain Houseleek (Sempervivum montanum) growing amongst rocks on scree slope. Nordtirol, Austrian Alps, July.

Philippe Clement / Common houseleek (Sempervivum tectorum) and Long-spurred violet (Viola calcarata) in flower, Val Veny, Italian Alps, Italy, June

Colin Varndell / Rock stonecrop (Sedum forsterianum) in bud. Portland, Dorset, UK, June.

Chris Mattison / Houseleek (Sempervivum sp, cultivar 'Koko Flanel') in cultivation.

Chris Mattison / Houseleek (Sempervivum sp, 'Col de Michel'), in rockery, France.

Kim Taylor / Cobweeb houseleek (Sempervivum arachnoideum) flowering. France, July.

Ernie Janes / Sempervivum plants for sale at garden centre, England, UK, June.

Chris Mattison / Houseleek (Sempervivum ciliosum borusii) a succulent alpine originating from Bulgaria

Paul Harcourt Davies / Cobweb houseleek (Sempervivum arachnoideum) in flower, Gran Sasso, Appennines, Abruzzo, Italy

Paul Harcourt Davies / Cobweb houseleek (Sempervivum arachnoideum) Gran Sasso, Appennines, Abruzzo, Italy

Juan Manuel Borrero / Mountain houseleek (Sempervivum montanum) Pyrenees, Spain, July

Alex Hyde / Houseleek (Sempervivum tectorum ssp. alpinum) growing on mountainside in Gran Paradiso National Park, Aosta Valley, Pennine Alps, Italy. July.

Alex Hyde / Common Houseleek (Sempervivum tectorum ssp. alpinum) growing on mountainside in Gran Paradiso National Park, Aosta Valley, Pennine Alps, Italy. July.

Alex Hyde / Cobweb houseleek (Sempervivum arachnoideum) growing amongst rocks, Gran Paradiso National Park, Aosta Valley, Pennine Alps, Italy. July.

Alex Hyde / Houseleek (Sempervivum grandiflorum) growing on rocky outcrop in Aosta Valley, Monte Rosa Massif, Pennine Alps, Italy. July.

Alex Hyde / Cobweb Houseleek (Sempervivum arachnoideum) Aosta Valley, Monte Rosa Massif, Pennine Alps, Italy. July

Chris Mattison / Pittoni's sempervivum (Sempervivum pittoni), cultivated, occurs in Austria

Gary K. Smith / Houseleek (Sempervivum sp) flower spike, UK, July

Ernie Janes / Houseleek (Sempervivum) on gravel bed, UK, June

Ernie Janes / Houseleeks (Sempervivum) and Succulents in garden with pottery urn, UK, June

Alex Hyde / Mountain Houseleek (Sempervivum montanum) growing amongst rocks on scree slope. Nordtirol, Tirol, Austrian Alps, Austria, 2500 metres, July.

Grzegorz Lesniewski / Mountain Web-houseleek (Sempervivum montanum). Krzemien Peak, Bieszczady National Park, the Carpathians, Poland, July.

Grzegorz Lesniewski / Mountain Web-houseleek (Sempervivum montanum) and Kopa Bukowska Peak. Bieszczady National Park, the Carpathians, Poland, September.

Wild Wonders of Europe / Lesniewski / Mountain web-houseleek (Sempervivum montanum). Bieszczady, Carpathian Mountains, Poland, July.

Wild Wonders of Europe / Lesniewski / Mountain web-houseleek (Sempervivum montanum). Bieszczady, Carpathian Mountains, Poland, July.

Paul Harcourt Davies / Cobweb houseleek (Sempervivum arachnoide) flowering in the Apennine mountains, Italy, Europe.

Paul Harcourt Davies / Common houseleek (Sempervivum tectorum) close-up, in flower, Apennine mountains, Italy, Europe.

Paul Harcourt Davies / Cobweb houseleek (Sempervivum arachnoide) flowering in the Apennine mountains, Italy, Europe.

Paul Harcourt Davies / Cobweb houseleek (Sempervivum arachnoide) flowering in the Apennine mountains, Italy, Europe.

Paul Harcourt Davies / Common houseleek (Sempervivum tectorum) close-up, in flower, Apennine mountains, Italy, Europe.

Robert Thompson / Cobweb house-leeks {Sempervivum arachnoideum} in flower, alpine meadows above Lac du Mount Cenis, Alps, France, July

Robert Thompson / Cobweb house-leek {Sempervivum arachnoideum} in flower, alpine meadows above Lac du Mount Cenis, Alps, France, July

Robert Thompson / Cobweb house-leek {Sempervivum arachnoideum} in flower, alpine meadows above Lac du Mount Cenis, Alps, France, July

Wild Wonders of Europe / Benvie / Mountain houseleek (Sempervivum montanum) in flower, digital composite, Fliess, Naturpark Kaunergrat, Tirol, Austria, July 2008

Wild Wonders of Europe / Benvie / Mountain houseleek (Sempervivum montanum) in flower, Fliess, Naturpark Kaunergrat, Tirol, Austria, July 2008

Wild Wonders of Europe / Benvie / Mountain houseleek (Sempervivum montanum) in flower, Fliess, Naturpark Kaunergrat, Tirol, Austria, July 2008

Philippe Clement / Close-up of Cobweb houseleek (Sempervivum arachnoideum) in flower, Gran Paradiso NP, Alps, Italy

Philippe Clement / Cobweb houseleek {Sempervivum arachnoideum} flowering on lichen covered rock, Gran Paradiso NP, Alps, Italy

Philippe Clement / Cobweb houseleek {Sempervivum arachnoideum} on lichen covered rock, Gran Paradiso NP, Alps, Italy

Philippe Clement / Cobweb houseleek {Sempervivum arachnoideum} flowering on Lichen covered rock, Gran Paradiso NP, Alps, Italy

Philippe Clement / Cobweb houseleek {Sempervivum arachnoideum} flowering on lichen covered rock, Gran Paradiso NP, Alps, Italy

Philippe Clement / Mountain houseleek {Sempervivum montanum} Gran Paradiso NP, Alps, Italy

Christoph Becker / Mountain houseleek flowering in rock crevice. (S.montanum) Swiss Engadine

Christoph Becker / Mountain houseleek flowering in rock crevice. (S.montanum) Swiss Engadine

Matthias Breiter / Mountain Houseleek (Sempervivum montanum) flowering, Vancouver, British Columbia, Canada

Jouan & Rius / Mountain houseleek (Sempervivum montanums) in flower on hillside, Massif du Diois, Vercors Regional Natural Park, Drome, France, July.

Philippe Clement / Common houseleek (Sempervivum tectorum) flowering on red tiles on house roof, Belgium. July.

Adrian Davies / Mountain houseleek (Sempervivum montanum) flowering among rocks, Swiss Alps, Switzerland. June.

Konrad Wothe / Cobweb Houseleek (Sempervivum arachnoideum) flowers, Alps, Switzerland

Konrad Wothe / Cobweb Houseleek (Sempervivum arachnoideum) flowers, Alps, Switzerland

Konrad Wothe / Cobweb houseleek (Sempervivum arachnoideum) in flower, Grisons, Switzerland, Europe. July.

Chris Mattison / Cobweb houseleek (Sempervivum arachnoideum) growing on rocks, Valgrisenche, Italian Alps, Italy.

Chris Mattison / Mountain houseleek (Sempervivum montanum) growing out of lichen covered rocks. Valgrisenche, Italian Alps, Italy.

Chris Mattison / Mountain houseleek, (Sempervivum montanum), Gran Paradiso National Park, Italian Alps, Italy.

Paul Harcourt Davies / Cobweb houseleek (Sempervivum arachnoideum) flowering amongst Moss between rocks. Dolomites, Italy. July.

Robert Thompson / Cobweb houseleek (Sempervivum arachnoideum) flowers, Pyrenees National Park, France, June.