Sempervivum globiferum subsp. allionii (Rollers), also knonw as Jovibarba globifera subsp. allionii, is a cute succulent with a…
Jovibarba (Joe- vih -BAR- buh ) is a small genus of just 3 distinct species native to the mountains of southeastern Europe. They are Jovibarba heuffelii (Hew-FELL-ee-eye), Jovibarba globifera (Glow- bih -FAIR-uh) and Jovibarba hirtum (HER-tum). All form attractive rosettes of low, colorful foliage. They are extremely cold hardy, thriving in climates as cold as zone 4. In time, these plants form lovely, thick mounds and make an excellent ground cover, though they will not tolerate foot traffic. Very similar to sempervivum, jovibarba are often called “the other hens and chicks”. Let’s take a closer look at the similarities and differences between jovibarba and sempervivum.
Jovibarba and sempervivum are very similar to sempervivum in their appearance, cold hardiness and care. The scientific names of plants truly matter. However, s ome botanists have classified jovibarba as distinct from sempervivum, then re-combined the two, leaving gardeners and vendors to often confuse the two and to use the terms nearly interchangeably.
Internationally, botanists have again filed jovibarba as a sub-genus of sempervivum. However, the Flora of North America classifies jovibarba as distinct from semps. Their judgement is based upon their flowering, the patterns of their propagation and their DNA which indicates the two genera divided between 5 and 9 million years ago. It is said that if you gather 3 botanists and a single plant in a room, they will emerge with 4 different names for the plant!
While sempervivum and jovibarba are undeniably similar, there is rich diversity within both groups. I think they both deserve to be better understood and appreciated. While genetic differences are persuasive taxonomically, it is primarily the differences in their color adaptability, flower forms and propagation that are of the most use and/or interest to the home gardener.
Both sempervivum and jovibarba (especially Jovibarba heuffelii) offer wonderful color interest in the garden, ranging from deep, vivid reds and burgundies to smoky purples, many shades of pink, brilliant orange and all shades of green. Sempervivum go through extraordinary color changes due to stress through the change of seasons. One sempervivum may develop from a pale peach to bright pink to a dusky violet all within a single year. Jovibarba, however, retain far more of their vivid coloring all year long.
Jovibarba heuffeli ‘Pink Skies’ illustrates another, more subtle coloring distinction between jovibarba and sempervivum. Both varieties produce tiny little hairs along the leaf margins called ciliate hairs Ciliate (SILL-ee-uht) hairs are a fringe of tiny hairs along. More . They collect dew, causing it to fall at the drip line, thereby providing the plant more moisture in an arid climate. However, the hairs on jovibarba are more pronounced and white. This gives a picotee look to each rosette as if each leaf were outlined in white. When the sun catches these hairs on the leaves, the jovibarba rosettes seem to glow. Subtle – but so lovely!
Often the blooms of two similar looking plants help botanists and gardeners to tell them apart. Such is the case between sempervivum and jovibarba — in bloom, you can easily tell them apart. First, the similarities: Both are monocarpic succulents, meaning the mother plant (the “hen”) blooms just once, then it dies. Both produce many offsets Succulent offsets are the baby succulents that form at the b. (the “chicks”) before blooming. The colonies continue to grow larger and lusher all the time. Sempervivum and jovibarba blooms are both highly attractive to butterflies and bees.
It is the appearance of the flowers that sets them apart. Jovibarba blooms are a pale yellow, with 6-12 petals each that remain mostly closed, so that each flower is bell-like in shape. Sempervivum flowers have 12-18 petals, ranging from yellow to vivid pink. They open wide, forming flashy, starry blooms.
Another clear distinction between jovibarba and sempervivum is the way their offsets develop. All are considered “hens and chicks” because the mother plant forms many babies clustered around it. On a sempervivum, these offsets are attached by a modified stem called a stolon A stolon (STOLE-ehn) is a horizontal root, growing just abov. . In time, the stolon dries up, and the baby plants root and grow beside the mother.
Jovibarba offsets are a bit different. Jovibarba heuffelii offsets develop within the primary rosette of the mother, between the layers of her petals. In time, if left to their own devices, they will form full-sized rosettes beside the mother plant. For the gardener to propagate at this stage requires surgery with a sharp knife — but again, this is not necessary for your collection of J. heuffelii to increase.
Jovibarba globifera and hirtum use a different strategy. They form many offsets, attached by stolons like the semps . However, the offsets remain closed up, round and ball-like, without rooting. When the stolon dries up, the babies roll away from the mother plant and come to rest some distance away, where they root and begin to grow. Consequently, these charmers are often called”roll-aways”, “rollers” or “Jovibarba rollers”.
Both sempervivum and jovibarba are completely non-toxic and safe to grow around pets and small children!
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For such beautiful, carefree, cold hardy plants, it surprises me that sempervivum and jovibarba are not more widely available to order. However, my all-time favorite succulent source —Mountain Crest Gardens — has an exceptional selection of each. They list them all under the genus name of sempervivum, though they do use the proper species and varietal names. Even better, they separate out their selection of Jovibarba heuffelii (which they label as Sempervivum heuffelii) from their regular sempervivum. They also offer several jovibarba rollers (globifera and hirtum varieties).
I hope you have enjoyed this review of the differences between jovibarba and sempervivum. Even better, I hope you will now choose to grow both jovibarba and sempervivum in your garden! For jovibarba care, please see my post on sempervivum. Aside from propagation techniques for Jovibarba heuffelii, you’ll find all of the care essentially the same. If you have any questions or comments for me, please leave a comment. I love it when you do, and I’ll be sure to get right back with a reply!
© Copyright: Images: Jouko Lehmuskallio.
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Rolling hen-and-chicks is a very popular rockery and stone garden plant in Finland. The plant takes a number of years to mature to a size that it is able to flower, after which it dies, so it is only rarely that its exotic inflorescence can be admired. The ornamental species is mainly a fleshy, globose leaf rosette. The rosette breaks off easily from the soil and the plant thus spreads organically from the place it was planted. Rolling hen-and-chicks can be found in Finland as an escape from cultivation in rocky habitats, in the driest and hottest places. Ornamental stands that have gone wild often present the botanist with a problem as the border between a leftover from cultivation, a casual escape and a truly feral plant is often difficult if not impossible to draw. Rolling hen-and-chicks’ natural habitat ends not far from Finland’s south-eastern border, so it is no surprise that the plant thrives here.
Sempervivum tectorum & Sempervivum arachnoideum
Rolling hen-and-chicks’ close relative common houseleek (Sempervivum tectorum) is a similar nectar plant that can often be found growing in old gardens. It used to be planted in Finland on tile and peat-roofed houses to prevent fires. It disappeared almost completely with the modernization of roof structures but it is persistent in the wild, often growing on rocks where the soil is impossibly thin. The plant grows ferally in central and southern Europe and in the mountains of western Asia. The other possible Sempervivum species in Finnish gardens and sometimes outside is cobweb house-leek.
Genus Sempervivum has 42 members, while genus Jovibarba has only 5. The former also cross-breed easily with each other, and breeders have produced hundreds of different varieties. Jovibarba differs from Sempervivum with regards to e.g. the rosettes that are formed at the end of its thin thread-like runners.
→ Distribution map (Kasviatlas, University of Helsinki)