Sempervivum arachnoideum

house leek
Unique cobweb appearance covers this tightly mounded alpine. Clusters of upright pink star flowers. Great in rock gardens, pots and cracks.
Sempervivum arachnoideumSempervivum arachnoideum
height 2–5in
width 6–18in
tolerates Cold, Drought, Pots, Wind
water
needs		 Moderate
water
info		 Sempervivums are drought tolerant succulents, wanting to go from wet to dry, but they’ll need additional water if they are grown in a particularly sunny hot spot, especially away from the coast or in a rock garden where the rocks will heat up the area. They are not so drought tolerant that they can survive without summer water.
hardy
to		 -20F
exposure Part Sun
indoor
outdoor		 Outdoor
drainage In Ground: Cactus Mix, In Pots: Cactus Mix
fertilizing All Purpose
origin Europe
california
native		 No
sunset
zones		 2–24

Sunset Zones Map

Outdoor Exposure Guide

Growing Notes

Sempervivums have a dense form, eventually creating a solid mat of tightly packed rosettes.
Sempervivums have such a shallow root system that they almost seem detached at times, and in fact this is by design, allowing them to roll or be blown to a new location, where they can begin a new life. Don’t be discouraged if you find your sempervivum growing on long thin “branches”! This is usually a sign that the plant has filled its pot/rock/crack and is heading out for a new home.
Their ability to grow in tiny spaces makes sempervivums a common addition to living succulent walls.
Each rosette will eventually throw off a short unfurling spike of star-shaped flowers. Afterwards that head will die off, replaced by pups, and it can be removed. Sempervivums bloom during summer months.
In areas of hot inland sun (where summer days regularly roll into the 80sF) this plant appreciates part sun or even full bright shade.

Special Interest

Sempervivum means “always-living,“ attesting to this plant’s durability in the garden and ability to grow in tough conditions with little soil.

Sempervivums were historically used in Europe as low care living roofs. Their shallow root system made them carefree and as an added bonus they resist fire, including from lightning strikes.

The common name ‘house leek’ refers to the edible young shoots, which can be eaten raw and are similar in flavor to a cucumber.