Sempervivum or the Houseleek is a mat forming, evergreen, perennial succulent.
Perfectly symmetrical rosettes of pointed succulent leaves form a carpet of foliage by producing offset rosettes, which increase the width-ward spread.
Most will produce small tubular, yellow or white flowers and once a rosette flowers it will usually die off.
There are quite a few species and varieties available, varying in size and colour.
Some of the most interesting ones are the Cobweb Housleeks that are coated in very fine, spiders web-like hairs that almost gives the impression that a spider has spun a web around the rosettes.
This is a useful succulent for rock gardens and for indoors and is very hardy in dry conditions.