Helleborus x sternii “Blackthorn Strain”
Helleborus x sternii “Blackthorn Strain”
Family: Ranunculaceae
(Buttercup family)
Common name: Hellebore
Description: H. x sternii is a caulescent (stem-forming) herbaceous plant 60-80cms in height with clusters of pale green flowers, each having five petals held in cymes, and glossy, glabrous leaves which are slightly marbled. An attractive pink venation can be seen in the leaf stalks and the flower bracts.
Areas of the garden where the plant is found: Beside the copper beech, mid-way along the Broadwalk in bed 7A.
Distribution, habitat and conservation status: The parents of this hybrid, Helleborus argutifolius and Helleborus lividus, both have a naturally restricted distribution. H. argutifolius is quite widepread in Corsica and Sardinia; H. lividus is an uncommon Majorcan endemic (a species native only to this island). Neither is considered threatened in the wild. Their habitat is light woodland or maquis.
Derivation of name:
The name hellebore was used by Theophrastus, although it is not clear whether he had in mind plants that would now be recognized as hellebores, or veratrums. From antiquity onwards, the name has nonetheless come to be associated with these plants.
History: Blackthorn nursery, one of several nurseries with a particular interest in hellebores, selected this form of H. x sternii. That hellebores hybridise easily is a source of pleasure to nurserymen and gardeners, who can enjoy choosing the best colour variants from seed-raised plants, and a source of frustration to taxonomists, who find real difficulties in drawing the line between some hellebore species. At the centre of distribution in the Balkans and SE Europe, the high degree of variability and frequent occurrence of natural hybrids creates a complex picture for botanists. Hellebores are difficult to micropropagate: consequently, the best hybrids are never available in large numbers.
Cultivation: Grow in light shade or full sun in neutral or alkaline soil. As with other hellebores, leaf-mould mulches are beneficial. Although H. lividus, one of the parents, is probably the most tender hellebore species, H. x sternii is considerably hardier. The tough, coriaceous leaves of H.x sternii mean it is much less vulnerable to the fungal leaf spots which can sometimes afflict H. x hybridus.
Points of interest:
The seeds are dispersed by ants. This mutualistic association of ant and plant (myrmecochory) benefits the ants because hellebore seeds provide food rewards (both lipids and proteins) in special structures, called elaiosomes. Hellebores are by no means unique in having this type of relationship with ants: there are frequent examples of myrmecochory among the South African fynbos flora, where ants effectively bury seeds of different plant species, protecting them from fire and allowing germination when conditions are right. For anyone who might not have time to visit South Africa and look at this astonishing flora in situ, it is worth noting that many beautiful fynbos plants can be found closer to home, growing in the Great Glasshouse at NBG Wales.
References
New RHS Dictionary of Gardening
Hellebores Brian Matthew 1989
www.hellebores.org
Wikipedia-article on Theophrastus
