Sempervivum

( sem - per - VYE - vum )

At-A-Glance Information

Commonly called Hens and Chicks or Houseleek, this genus of succulent perennials includes species which need light shade in hotter climates and little to moderate amounts of water to perform well in the landscape. These succulents are native to a region that spans from southern and central Europe through southwest Asia and Northwest Africa. Hens and Chicks are known for their multitudinous offsets (hence their common name) and form tightly-packed rosettes of green fleshy leaves. Flowers appear in summer and can be yellow, pink, red, or green. Individual rosettes will perish after they bloom, but by that time offsets will have formed. Sempervivum plants can be used in the ground or in containers, and are at home in drought tolerant, succulent and cacti, or rock gardens. They can also be used as edging along pathways, in mixed beds and borders, in wall crevices, or as a no-traffic groundcover. These succulents are also commonly featured in living walls and green roofs.

Sempervivum Species and Varietals

The genus Sempervivum is a member of the plant family Crassulaceae and includes 40 to 51 distinct species. The plants in this genus are closely related to those in Sedum (Stonecrop) and Echeveria (Mexican Rosette). These succulents grow best in USDA hardiness zones 3-9 or Sunset growing zones 2-24. To find your zone, click here: Zone Map.

Sempervivum arachnoideum (Cobweb Houseleek, Cobweb Hens and Chicks)
This species forms grey-green rosettes whose leaves are connected by thin silvery hairs. It spreads slowly to form a dense mat 1 foot or wider. Flowers appear at the end of 4-6 inch tall stems and are bright red. Cultivars include 'Emily' (tight rosettes with white fuzz), 'Robin' (deep red-rose rosettes covered in silvery hairs), 'Rubrum' (ruby-red rosettes covered in white cobwebs), 'Viridescens' (green rosettes with burgundy outer leaves), 'Cebenese' (pictured; green leaves with burgundy-flushed tips in spring) and 'Cobweb Buttons' (covered with geometric web patterns).

Sempervivum calcareum (Jovibarba globifera) (Lime Houseleek, Limestone Houseleek, Limestone Liveforever, Chicks and Hens, Calcareous Houseleek, Old Man and Woman, Roof House Leek)
This species is native to the southern Alps, and forms rosettes of thick green leaves with reddish-purple tips. Individual rosettes reach up to 2.4 to 4 inches wide, and form mats that spread to reach 5 to 12 inches wide as they produce offsets. Cultivars of this species include 'Extra' (with silver-grey leaves tipped with deep purple-brown), 'Guillaumes' (green leaves tipped with brown), and 'Sir William Lawrence' (light green foliage tipped with maroon).

Sempervivum globiferum (Rolling Hen-and-Chicks, Rollers, Molodilo, молодило)
This species is unique in that it produces offsets that detach from the parent plant and roll away to grow in new locations. Rosettes are rounded and typically green, sometimes flushed with red. Leaves are pointed and can have hairs along margins. Flowers form atop thick, erect stems and are pale green to yellow. The species is native to a region that spans from Germany to European Russia.

Sempervivum hybrids
These plants form crowded rosettes of varying colors and shapes, and are widely sold at nurseries and other plant sellers. Cultivars are listed and described below:

'Black'
Green leaves mature to a dark maroon color.

'Krebs'
Chocolate-green foliage.

'Oddity'
Burgundy-tipped green foliage that form tubes. 8 in. tall and a foot wide.

'Rubikon'
Red rosettes.

Sempervivum pittonii (Pittoni Houseleek, Pitton's Houseleek, Houseleek, Hens and Chicks)
This species is native to the eastern Alps in Austria, where it grows on serpentine rock. It is cold-hardy, and grows well in USDA hardiness zones 4a-9b and is hardy down to -30 degrees Fahrenheit. Individual rosettes reach up to between 1 and 2 inches wide and form low-growing clumps and clusters that can spread to 10 inches wide. Flowers are green-yellow to bright yellow.

Sempervivum tectorum (Hen and Chickens, Common Houseleek, Jove's Beard, Fuet, Jupiter's Eye, St. George's Beard, Thunderplant, Thor's Beard, St. Patrick's Cabbage, Homewort, Sengreen, Roof Foil, Poor Jan's Leaf)
This species of Sempervivum forms grey-green 2-5 inch wide rosettes and spreads quickly to form clumps around 2 feet wide. Foliage is red-brown at the tips, and tips are also bristled. Varieties come with differing leaf colors, including red, purple, chartreuse, and silver-blue. This is the most widely recognized species in the genus, and has been known to humans for thousands of years, earning many common names along the way.

Caring for Sempervivum

Plant Sempervivum succulents in a space in the landscape that receives full sun to partial shade; ideally, they appreciate between 6 and 8 hours of sun each day for the best red, purple or golden tones. The more sun these succulents get, the tighter rosettes will form. In regions with intense summer heat (above 90 degrees Fahrenheit), provide Sempervivum plants with afternoon shade to prevent leaf scorch and sunburn. Ensure that soil is well-draining, rich in nutrients, and has a circumneutral pH of between 6.0 and 7.5 (slightly acidic to slightly alkaline). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of rock or organic mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants are considered drought-tolerant, able to get by on rainwater alone for much of the year with supplemental waterings during extended periods of dry, warm weather. Allow soil to dry out completely between waterings.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. Sempervivum plants form individual monocarpic rosettes that can persist for 3 to 4 years before they flower and perish, though they can live indefinitely by producing offsets and forming colonies.

Caring for Sempervivum in Containers
Sempervivum plants do well in the ground but can also be grown in containers. Choose a container that is at least a few inches wider and deeper than the nursery pot or root ball. Ensure that the pot has adequate drainage holes on the bottom to allow for excess water to flow away. These plants prefer a rocky or sandy substrate that is well-draining. Top with a layer of rock mulch to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly as the plant establishes itself in its new home. Once established, waterings can be lessened. Sempervivum plants grown in containers will need more frequent irrigation than those grown in the ground. As a general rule of thumb, water whenever the top few inches of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. Every few years, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot.

Propagation

The best way to propagate Sempervivum is by cutting in springtime. To propagate your succulent, you will need a clean, sharp knife or garden shears and a pot filled with a well-draining potting mix (if you will not be replanting in the ground). When you have gathered your materials, follow the directions below to propagate your plant:

Use your clean, sharp garden shears or knife to cut off a piece of stem with leaves. Place this cutting on its side and leave it in a dry, warm, shaded spot for at least three days. This will cause the root end to heal and form a hard callous. Doing this helps the plant avoid root rot when it gets planted in potting mix.
Fill your pot with the potting mix described above, and then place the calloused end of your cutting into the soil. Push down until the cutting can stay upright without assistance. Place the pot in a spot that receives bright, indirect light and water lightly once a week. Do not allow the soil to become too moist or dry out completely.
Your cutting should grow roots in about two weeks, whether or not it is placed in potting medium. To check for roots, lightly tug on the plant. If it resists, you have roots.

Problems and Pests

Sempervivum are typically resilient in the landscape, though they can have issues from time to time with the following pests and diseases if growing conditions are not met: