Sempervivum arachnoideum Rubrum

Sempervivum arachnoideum Rubrum is a beautiful purple form of the cobweb houseleek, an alpine species that owes its name to the fine veil of white bristles stretched around small rosettes, as if they were trapped in a spider's web. These fine sparkling bristles, woven on the triangular leaves tinged with purple, further accentuate their geometric appearance. One fine summer day, like a pleasant surprise, a small stem of pink star-shaped flowers emerges from the heart of the oldest rosettes. This houseleek is a small succulent plant, ideal for arid and mineral areas. It requires nothing more than an open location. Without any maintenance, it miraculously survives almost without soil, in a dry, poor, siliceous or limestone environment, and relies on rainwater, even if it is scarce.

From the Crassulaceae family, this cobweb houseleek is proof that poor soil and a mineral landscape can accommodate beautiful specimens with vibrant colours. In its natural environment, it lives on rocks or scree, dispersing its fine seeds in crevices and clinging to the smallest cracks to slowly form small colonies of rosettes of different sizes, juxtaposed, not exceeding 8cm (3in) in height. Over time, it uses its stoloniferous stems to form a carpet spreading up to 60cm (24in) on the ground, perfectly adapting to the terrain. Resembling small artichokes measuring 1.5 to 3cm (1 to 2in) in diameter, each rosette is composed of numerous fleshy, pointed leaves, without petioles, connected to each other by a silky, dense weaving. The white threads, stretched between the leaves, shine in the sun. Their purple colour intensifies in the sun or under the effect of cold. The roots of this perennial are thick and long; they penetrate deeply into rock crevices, ensuring a good grip on the walls while drawing water from deep sources. Flowering appears on rosettes aged 2 or 3 years, which will then disappear, having ensured the plant's perpetuity by producing several small peripheral rosettes. The flowering develops in summer, formed by thick stems that bear 1 to 5 flowers with 8 to 10 light pink petals around a green centre.

Sempervivum arachnoideum Rubrum is a blessing for gardens with lean soil, where few species survive. It easily colonises abandoned spaces. If your soil is poor, rather dry, rocky, stony, or even slightly limestone, you can still enjoy this hardy perennial (which withstands temperatures below -15°C (5°F)). It requires no maintenance and promises to bring life to any pile of stones, a low wall, or even a green roof. Houseleeks are extremely easy to grow, offering flowers and foliage in various shades that create stunning compositions. They look magnificent in pots, especially in low terrine-type pottery, and are irreplaceable in borders, troughs, or rockeries, along with sedum, London pride (Saxifraga umbrosa), wall bellflowers, or Lewisia cotyledon. These miniature perennials quickly inspire the desire to multiply them. Consider choosing companions with staggered flowering times and colourful foliage for a variegated and joyful rockery.