Sempervivum arachnoideum, spider's web houseleek

Not all succulents grow at the other end of the world. Spider's web houseleek (in Latin, Sempervivum arachnoideum) lives in Europe, in the Alps and Pyrenees. Easy to care for, this member of the Crassulaceae family can be grown in the garden, in rock gardens or as ground cover.

How to recognize spider's web houseleek, Sempervivum arachnoideum?

Spider's web houseleek is a succulent plant with a bushy habit. It is short, growing to a height of no more than 15 cm when in flower.

The rosette of leaves measures no more than four centimetres in diameter. The fleshy leaf blades are green and pointed at the apex. Hundreds of white threads link the tips of the leaves together. Silky, they form a lace-like veil or spider's web. As with sempervivum ciliosum, they help retain moisture.

Sempervivum arachnoideum flowers in summer. Pink flowers bloom on 10-centimetre flower stalks. They have eight to ten petals with darker veins. After flowering, cobwebs die. But it takes the time to produce shoots to multiply.

Not all specialists agree. For some, it's harmless. For others, it is slightly toxic to animals and humans if ingested.

Our maintenance tips

Spider's web houseleeks are easy-living outdoor plants. All they need is a sunny spot and a well-draining substrate. They can flourish on a roof, in the crack of a low wall or in a rockery. You can also grow them in pots. There's just one rule: don't mix them with other species, which might take over.

Watering

Only water your Spider's web houseleek when the substrate is dry. If you're not sure what your plant needs, observe it: when it's thirsty, its leaves become hollow and stunted.

Avoid tap water, which is often too hard. Instead, use room-temperature rainwater or demineralized water.

Thirty minutes after watering, empty any stagnant water from the saucer or planter to prevent root rot.

Spray

Spider's web houseleeks grow in arid regions and do not like humidity. No need to spray them.

Repotting

In spring, transfer your Sempervivum arachnoideum to a larger pot, so that it can continue to grow.

Obtain a pierced terracotta pot. Line the bottom with a layer of clay balls or gravel. This way, in the event of over-watering, your plant won't get its feet wet.

Add a mixture of garden soil (50%) and sand or pozzolan (50%). Plant your Spider's web houseleek in the center. Tamp and water to remove air bubbles.

Prune

Remove dried leaf rosettes after flowering.

Plantation

Once the last spring frosts have passed, you can plant.

Choose a sunny, well-drained spot, such as the top of a slope. Loosen your soil by scratching it. If your soil is compact, add sand, crushed pozzolana or gravel to lighten it.

Dig a hole the size of the root ball and plant your Spider's web houseleek. Space the different plants at least 20 cm apart to give the shoots room to develop. Don't plant other, larger varieties nearby. They may overshadow and take over the whole space.

Tamp and water to help the plant take root.

Cutting

Cutting is carried out during the strong growth phase, generally in spring and early summer.

Take the shoots that form at the base of your Spider's web houseleek. The larger they are, the greater the chances of success. Choose shoots with several leaves.

Cut off the new plant and its roots with a clean, sharp blade.

Obtain a perforated pot. Add a layer of clay balls or gravel to the bottom for drainage.

Mix equal parts garden soil and sand or crushed pozzolan. Plant spider's web houseleek in the center. Tamp gently and water generously to encourage rooting.

Disease / Threat

Rust

Information

Family	Crassulaceae - Crassulaceae
Type	Joubarbe - Sempervivum
Species	Spider's web houseleek - Sempervivum arachnoideum
Lifecycle	Perennial
Foliage	Evergreen
Exposures	Sun Half-shade
Substrats	Calcareous earth Humus soil Sandy soil
Planting methods	Open ground In pots Planter
Categories	Rhizome Herbaceous Succulent
Tags	Beginner Flowery Increvable Rustic Toxic
Origin	Southern Europe
Hardiness (USDA)	4b
Leaf color
Flower color