Sempervivum arachnoideum 'Cobweb' is a compact, cold-hardy succulent that forms tight rosettes threaded with silvery white "cobweb" fibers. You can tuck it into crevices, rock gardens, troughs, and sunny containers where sharp drainage is guaranteed, and let it slowly multiply into a colony of offsets.
Give your plant full sun for the best color and tight growth; it will also tolerate part shade, especially where summers are hot. Plant it in gritty, fast-draining soil and keep the crown sitting above wet soil so it does not rot. Water deeply, then let the soil dry out; once established, it handles drought well, but it will look best with occasional watering during active growth.
This plant stays low (about 3-4 inches tall) and spreads as it produces "chicks" around the original rosette. You can gently separate offsets and replant them to fill gaps or start new pots. Flowers appear in summer on a taller stalk; after blooming, the flowering rosette dies, but the surrounding offsets keep the colony going.
For year-round success, prioritize drainage in winter and avoid rich, soggy mixes. Use it as a tidy edging accent, a small-scale groundcover in dry sites, or a textural filler between rocks where other plants struggle.