Echoing the aesthetically pleasing rosette shape of Echeveria, Sempervivum achieve the same visual appeal in a far more resilient package. For starters, unlike other succulent varieties these European plants are especially cold hardy, and can survive cold temperatures down to Zone 3, opening up a world of possibilities for gardeners who otherwise thought it impossible to include succulents in their outdoor landscapes or containers. Commonly referred to as ‘hens and chicks,’ because of how readily they produce multiple offsets from a single parent plant, these beauties are easy to grow with only a few key tips to bear in mind. Indeed, their Latin name speaks to their resilient nature, meaning “always alive!”
Sempervivum grow in tight, low clumps, characterized by a profusion of tightly layered rosettes. Their leaves can be glossy or matte, and exhibit a range of colors and other unique traits. Sempervivum ‘Ruby Heart,’ for instance, puts on a show with its blush pink leaves topped with vibrant magenta tips and margins. Sempervivim ‘Cebenese,’ on the other hand, is a standout not for the color of its apple green leaves, but for the swirls of wooly hairs that top them, giving the plant an almost web-like appearance.
Considered monocarpic, meaning that each individual rosette only flowers once before dying off, mature Sempervivum will send up bloom stalks topped in long-lasting, star-shaped flowers in hues of pink, red, or even yellow. Once the flowers begin to senesce, that rosette will die, allowing the surrounding offsets to fill the vacated space.
Sempervivum can tolerate a range of lighting conditions, from bright to partially shaded. If your Sempervivum will be living outdoors, be sure to acclimate them to direct sunlight slowly, to avoid burning the leaves by making the transition too rapidly. While these plants can tolerate intense sun and intense heat, they perform the best when they are not subjected to both at the same time.
Extremely drought hardy, Sempervivum thrive on infrequent but thorough watering – as little as once a month should be sufficient, in all but the hottest and driest of conditions. Plan to water even less as temperatures dip towards freezing to avoid leaving the roots in cold and soggy conditions, which can predispose plants to rot.
Like most succulent types, a porous and well-draining soil mix is the name of the game for Sempervivum. If planting in a pot, a conventional cactus mix should be sufficient to keep the roots dry and happy. If planting directly into a garden bed, however, take care to ensure that the soil is not too dense with clay or organic matter, amending with course sand, pumice, or gypsum if necessary.
Sempervivum readily offset via stolons, or creeping stems, allowing these plants to quickly form a dense mat of foliage. As such, the easiest way to propagate these varieties is to gently lift an offset away from the parent plant, snip the stolon connecting the two, and replant the offset into porous soil in its own pot. Newly repotted offsets will require slightly more frequent watering as they establish their root system – but once growth is evident, revert to the more infrequent watering schedule preferred by mature Sempervivum.