This humble evergreen perennial goes by several common names including ‘Hens & Chicks’ (alluding to its capacity to produce offsets) and ‘Houseleek’, a reference to these plants being grown on roofs for protection from lightning as they were closely associated with Jupiter the Roman god of sky and thunder. Even its Latin name, Sempervivum, literally means ‘forever living’, which is an apt description for this bulletproof perennial.
Native to alpine regions of central Europe, Morocco, and parts of the Middle East, their thick, fleshly leaves and ability to retain moisture makes them quite tolerant of drought and temperature extremes, with most of the forty species being hardy to USDA zone 3 or 4. They primarily reproduce asexually by creating new offsets on short stolons, forming dense mats. Sexual reproduction from seed is also possible (self-pollination is quite difficult), although once a mature rosette produces its starry red, pink, or yellow flowers on short stems, they typically die.
Growing Sempervivum Indoors
Sempervivum have been enjoying a bit of a revival of late, much in part to the immense interest in indoor succulents. Thankfully, this family can be grown inside quite successfully, provided you follow a few simple rules:
place them in a bright south-facing window (at least 6 hours of sun) or use a grow light,
plant them in nutrient-poor soil (½ potting soil with ½ grit) in pots with drain holes,
mulch the soil surface with pebbles or fine gravel,
provide good ventilation (to avoid fungal problems),
do not mist the foliage, and
use fertilizer very sparingly indoors, if at all.
One other piece of good news is that Sempervivum do not contain any toxic compounds and are safe around children and pets.
Growing Sempervivum Outdoors
Outdoors these versatile plants make an excellent addition to alpine gardens, well-drained cracks in stackwalls, or even those dry south or west-facing foundation beds under the eaves of the house. Containers are another option and are only limited by your imagination as I have seen them adorn miniature troughs collected with other succulents or even spilling out of old hiking boots wired to a fence post.
Given the amazing range of colour options, mixed tapestries of foliage and texture are easy to achieve and are very aesthetically pleasing. You can even push your outdoor Sempervivum a little in order to flesh out those mixed displays by fertilizing with 20-20-20 at ¼ strength when the plants are in growth. Other conditions to look for include providing full sun exposure, avoiding wet or moist soils, and topdressing the soil surface with some grit or fine pebbles. That last requirement really came into play locally this past winter with that heavy snowfall, as excess moisture from the melt caused prolonged wet soil surfaces that led to many Hens & Chicks rotting out.
Sempervivum Foliage Textures and Colours
Now we get to the fun part, a brief introduction to the myriad of foliage textures and colours available. First of all, many Sempervivum change colours throughout the year, often displaying their most vibrant hues from late winter to early spring. Perhaps the most dramatic foliage can be found in the newer CHICK CHARMS series with dazzling colours found in ‘Gold Nugget’ (yellow w/ flaming orange tips), ‘Cosmic Candy’ (hairy burgundy-red with green centers), ‘Lotus Blossom’ (cherry-pink w/ sage green and white margins), ‘Cranberry Cocktail’ (burgundy with chartreuse highlights), and ‘Gold Rush’ (burgundy-red tipped in yellow) — and for those of you who can’t make up your mind, they also provide multi-planted pots known as ‘Candied Campfire’ with three different Sempervivum in each container.
Even what we consider "ordinary" Hens & Chicks provide dazzling foliage colours, including violet-silver (‘Proud Zelda’, ‘Belladonna’, ‘Purple Beauty’), rich reds (‘Robin’, ‘Commander Hay’, ‘More Honey’), enticing greens (‘Pyrenaicum’, ‘Fuzzy Wuzzy’), and bicolor (S. calcareum, ‘Sir William Lawrence’, ‘Ruby Heart’, ‘Compte de Congae’).