About the genus
Jovibarba is always associated with Sempervivum, but the name Jovibarba is used for plants that do not produce new offsets on stolons, and have tube-shaped creamy flowers with fringed petals – hence the common name ‘Jove’s Beard’.
The latest DNAstudies do separate Jovibarba from Sempervivum,but it is reduced to just two species – one with five subspecies.
Officially Jovibarba is still treated as a section of Sempervivum. In cultivation there are scores of selections with cultivar names and several interspecific hybrids. Jovibarba do not hybridise with Sempervivum.
Jovibarba heuffelii is the type species, growing in isolated pockets throughout the Balkans into the Carpathians. Even in the wild on a single rock face, plants can be variable. In cultivation, plants are generally much slower than Sempervivum as they produce a thick, fleshy rootstock from which new rosettes appear.
How to grow them
Both species are totally hardy but, although they can stand any amount of cold, with a repeated downpour-freeze-thaw cycle, a feature that is common to many parts of the UK in winter, pots are best put on their sides in the worst of the winter. After all, most plants in the wild grow on cliffs with very rapid drainage and are protected by dry snow during mid-winter.
Plants are generally pest-free though a large collection in Jersey was almost wiped out by vine-weevil, the grubs of which hollow out the rootstocks. Nibbling at leaf-edges are a sure sign of weevils. If there is a period of prolonged rain, botrytis may appear on leaves but is easy to eliminate with a rose fungicide. Birds often leave peck-marks on plants but no lasting damage ensues.
All plants are unfussy about substrate as long as it is well drained. Avoid peat and sharp sand.
The leaves of Jovibarba range from plain green to shades of red through violet to almost black. Unlike other succulents, keeping them in shade rather than full sun, brings the colours out best. Growing from seed is not difficult but do not expect the progeny to match the colour of the parent.
Propagation of Jovibarba heuffelii requires cutting the rootstock with a sharp knife and leaving to dry before replanting.
Jovibarba globifera has fibrous rootstocks with new rosettes appearing at the edges of plants between leaves. Sometimes (especially with subsp. globifera, ‘tumblers’ roll off the mother plant to root elsewhere.
Text and photos: Ray Stephenson
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