Hens and chicks

Identification and origin

Sempervivum tectorum belongs to the stonecrop family, Crassulaceae, along with sedums and jade plant. It is native to the mountains of central and southern Europe, from Spain and France to Germany, Switzerland, Austria, Italy, Hungary, and the Balkans. It has naturalized across much of Europe and in North America.

It is an evergreen succulent that forms dense mats. Each rosette, about 4 in across and roughly as tall, holds fifty to sixty thick, smooth leaves 2–3 in long, often tipped with purple. Its color shifts with the seasons and temperature, sometimes turning from green to red.

The mother rosette, the “hen,” sends out horizontal stems called stolons in all directions. Small rosettes, the “chicks,” form at their tips and root in turn, which is where the common name comes from. After two or three growing seasons, a mature rosette can bloom in summer. It then sends up a leafy, hairy flower stalk 6–12 in tall, topped with star-shaped red-purple flowers. After blooming, the flowering rosette sets seed and dies, and the offsets fill in its place.

The name Sempervivum means “always alive” in Latin, and tectorum means “of roofs.” In Europe it was once planted on rooftops, among other reasons to protect the house from lightning, a tradition dating back to the Romans, or to help hold slates in place.

A few selections are grown: ‘Emerald Empress’, with green to blue-green rosettes edged in red to purple and purple flowers; and the form Andorra, with green leaves tipped and centered in red, tinged pink to lavender in winter.

Light

Grow it in full sun, with at least six hours of direct sun a day. It tolerates light shade, and in very hot, sunny spots it even welcomes some afternoon shade. Make sure neighboring plants don’t smother it as the season goes on, and cut them back if needed.

Watering

Hens and chicks handles drought very well and grows in dry to medium-moisture soil. Too much water is what kills it, by causing crown rot. Always let the soil dry out between waterings.

In the ground, it seldom needs watering, though it appreciates a drink during a very dry spring or summer. In containers, check the mix: water when it is dry all the way through, then let the excess drain freely. In winter it needs no special care beyond protection from excessive wet.

Potting mix

Perfect drainage is essential. It likes lean, sandy or gravelly soil with a neutral pH, and it thrives in rock gardens, wall crevices, between stones, along edges, and on green roofs.

For containers, make a very free-draining mix: one part peat-free potting mix, one part loam-based mix, and one part coarse sand; or half grit and half loam-based mix; or a ready-made cactus mix. Top-dress with gravel or crushed slate to keep the crown clean and dry and to show off the rosettes. Container plants can receive a slow-release fertilizer, then a monthly liquid feed during the growing season once it runs out. In the ground, no fertilizer is needed.

Temperature

Hens and chicks is very hardy: it is grown in USDA zones 3a to 8b and handles harsh winters without protection. Frost does not harm it; prolonged winter wet is what can. If you live in a very rainy region, move containers into a cold frame for winter or shelter plants with a clear panel set above them.

Repotting

Plant it preferably in spring so it settles in during the warm season, at the same depth it grew in its nursery pot, firming gently. It is happy in shallow containers: pans, troughs, old bricks, gutters, or planters.

Every two to three years in spring, tip out container plantings, separate the rosettes, clear out dead material, and replant in fresh mix. This is also the time to fill gaps left by rosettes that have bloomed. Keep in mind that a clump rarely grows taller than 6 in when not in bloom, but spreads to at least 12 in.

Pruning

No pruning is needed. After flowering, remove the dead rosette along with its stalk to make room for the offsets. If you don’t want self-sown seedlings, cut off the stalk as soon as the flowers fade, before seed forms.

Propagation

Separating offsets is the most reliable method, since it gives plants identical to the parent. In spring, gently detach the small rosettes; many already have roots. Plant them in a gritty mix, keep them lightly moist and out of direct sun, and they should establish in four to six weeks. If an offset has no roots yet, snip the stolon close to the rosette and press it lightly onto the surface of a gritty mix; keep it moist until new leaves appear. Clumps in the ground can also be divided in spring when they start to look sparse.

Seed works for the species, which comes true if it has not been cross-pollinated by another houseleek; named varieties, however, do not come true. Keep the seed tray in a sheltered, frost-free spot such as a cold frame, and move the seedlings into a gritty mix as soon as they are large enough to handle.

Common problems

• Rosette dying after bloom: normal; the offsets take over.
• Crown or root rot: overwatering, poor drainage, or prolonged winter wet.
• Smothered rosettes: overly vigorous neighbors shading them; cut those back.
• Rust, leaf or stem rot: remove affected rosettes and check drainage.
• Plant declining: give it a gentle tug; if it comes loose easily, tip it out to inspect the roots, which can be rotten or eaten by vine weevil larvae.
• Tunnels in the leaves: sempervivum leaf miner, a pest that has recently appeared in the United Kingdom.
• Young plants pulled up: birds sometimes dig them out; stretch a few taut threads above them while they root.

The same symptom can have several causes, so always look at drainage, watering, exposure, and roots together.

Toxicity

No toxicity has been reported for dogs, cats, or people. As with any plant, an animal that chews the leaves can still have a mild, short-lived upset stomach.