Sempervivum arachnoideum 'hookerii'

Perennial succulent of the Crassulaceae family, this cultivar is related to the species Sempervivum arachnoideum, sharing its alpine origin and cobweb-like character. The name 'Hookerii' is old in specialized horticultural literature, but its precise taxonomic status — stabilized cultivar or selected form — remains debated; it is preferable to treat it as a garden name established by usage.

What immediately distinguishes this cultivar from the type species is the significantly larger size of its rosettes, which can reach 3 to 5 cm in diameter, and the remarkable density of the white web covering them, sometimes almost entirely masking the underlying foliage. The rosettes, medium green to grayish-green with leaf undersides tinged with reddish-brown, multiply abundantly by short stolons and quickly form tight, domed cushions with a very dense appearance. The overall coloration varies according to the season and exposure, from silvery green to dark red.

The flowers, bright pink to carmine pink, bloom on fleshy stems 10 to 15 cm tall. In cultivation, flowering generally occurs in July-August.

Like the type species, it thrives in full sun, in a very well-drained and poor substrate, without excessive watering. It withstands cold winters with ease and is perfectly suited for sunny rock gardens, containers, and walls.