Cobweb Houseleek

Sempervivum arachnoideum, the cobweb houseleek, forms an evergreen mat of small fleshy rosettes with white hairs webbing across green or reddish leaf tips. Starry pink flowers rise above the rosettes in summer; the RHS lists foliage up to 10 cm and flowering stems up to 12 cm. ## Growing conditions Give it a sunny position and well-drained loam or sandy soil. The RHS lists a spread of 0.1–0.5 metres and describes the plant as suitable for an alpine rockery. The existing size labels and USDA-zone values are retained because the RHS height is a maximum and its hardiness rating uses the UK scale. ## Garden use Use it in rockeries, gravel planting or containers where its small rosettes and cobweb-like hairs are visible. Keep its aliases together: the RHS also uses “cobweb sedum” for this species. [Royal Horticultural Society](https://www.rhs.org.uk/plants/17075/sempervivum-arachnoideum/details) ## Maintenance After a rosette flowers it dies back, while stolons form offsets that can fill nearby gaps. The RHS genus guide describes this replacement growth and recommends open, well-drained conditions. [RHS Sempervivum guide](https://www.rhs.org.uk/plants/sempervivum)