Sempervivum arachnoideum, commonly known as Cobweb Houseleek, is a species of flowering plant in the family Crassulaceae, native to the Alps, Apennines, and the Carpathians. The name translates to ‘always alive spider web.’
Sempervivum arachnoideum is a low-growing succulent reaching a height of about 3” inches. Each rosette measures about 1” – 1.5” inch in diameter whereas the entire plant spreads approximately 8” – 12” inches wide. The mother rosette, known as the Hen, spreads in a circular pattern by growing horizontal stems in every direction. These stems produce new rosettes called offsets or chicks. Each new rosette becomes independent of the mother rosette by developing its own root system before detaching itself from the connecting stolon. Cobweb houseleek is a relatively fast-growing succulent, but it is monocarpic which means it dies after flowering. Sempervivum arachnoideum blooms excessively from mid to late summer when fancy pink flowers dominate over the short, fleshy foliage. The Hen rosette produces a thick pinkish-red flowering stalk bearing a star-shaped flower with bright pink petals.