Sempervivum arachnoideum x tectorum

This cultivar is a fusion between the common houseleek (Sempervivum tectorum) and the cobweb houseleek (Sempervivum arachnoideum).

It is sometimes known and sold under the name Sempervivum x fauconnetii.

There are multiple theories as to why the hairs arrange themselves across the tips of the leaves.

1. 1. Water Optimization – Thick pubescence on leaves is often a method to reduce water loss and desiccation. The hairs break up airflow on the leaf surfacem reducing evapotranspiration across the surface of the leaves.
   2. Shade – Sun in xeric or high altitude environments can be brutal on small succulent plants, so a little self made shade can help. I have observed that the filaments become more numerous and more densely packed in the summer, especially if they are exposed to direct sunlight.

What are your experiences with the threads of a Sempervivum arachnoideum x tectorum?

🌸 Floral Morphology

Sempervivum × arachnoideum × tectorum forms tight, symmetrical rosettes with fleshy, pointed leaves that are gray-green to bluish-green.

Many rosettes display fine, cobweb-like hairs inherited from S. arachnoideum, giving them a distinctive texture.

During summer, erect flower stems rise above the rosettes, bearing star-shaped flowers in shades of pink to red.

Each flower is small but attractive, with multiple petals radiating from a central cluster of stamens, creating a classic houseleek bloom.

🌱 Reproductive Biology

This hybrid primarily propagates vegetatively through offsets, or “chicks,” which grow around the mother rosette, forming dense mats over time.

While the flowers are hermaphroditic and can be pollinated by insects such as bees, many hybrids are partially sterile, so sexual reproduction is limited.

The plant’s propagation strategy ensures survival and rapid colonization in suitable habitats.

🌍 Ecology & Adaptations

Native to alpine and subalpine regions of Central and Southern Europe, this hybrid thrives in rocky, sandy, and extremely well-drained soils.

It is highly drought-tolerant, storing water in its thick leaves, and tolerates full sun. The cobweb hairs on the leaves protect against intense sunlight and reduce water loss, while the rosettes can close in response to extreme heat or frost.

These adaptations make it ideal for rock gardens, alpine gardens, walls, and xeriscaping, providing both visual interest and resilience in harsh environments.

Other Names:

Houseleek

Origin:

Southern Europe