''Prunus'' × ''eminens'' or ''Prunus eminens'' is a species of small

cherry A cherry is the fruit of many plants of the genus ''Prunus'', and is a fleshy drupe (stone fruit). Commercial cherries are obtained from cultivars of several species, such as the sweet ''Prunus avium'' and the sour ''Prunus cerasus''. The nam ...

tree native to central Europe. It is a naturally occurring hybrid of sour cherry, ''

Prunus cerasus ''Prunus cerasus'' (sour cherry, tart cherry, or dwarf cherry) is a species of ''Prunus'' in the subgenus '' Cerasus'' ( cherries), native to much of Europe and southwest Asia. It is closely related to the sweet cherry (''Prunus avium''), but ...

'', and dwarf cherry, ''

Prunus fruticosa ''Prunus fruticosa'', the European dwarf cherry, dwarf cherry, Mongolian cherry or steppe cherry is a deciduous, xerophytic, winter-hardy, cherry-bearing shrub. It is also called ground cherry and European ground cherry, but is not to be confus ...

'', occasionally found where their ranges overlap. Like its parents, it is a

tetraploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains ...

with 32 chromosomes. It is forming a hybrid swarm with, and threatening to extirpate, ''P.fruticosa'' in much of its western range through

genetic pollution Genetic pollution is a controversial term for uncontrolled gene flow into wild populations. It is defined as "the dispersal of contaminated altered genes from genetically engineered organisms to natural organisms, esp. by cross-pollination", but ...

Description

It is difficult to distinguish ''P.''×''eminens'' from ''P.fruticosa'' based on vegetative characters alone. This task is made even more complicated by the high level of genetic

introgression Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Intr ...

from ''P.''×''eminens'' to ''P.fruticosa'', such that pure specimens of ''P.fruticosa'' might not be available for comparison. It is a small tree, usually 3 to 5m tall, with very rare specimens reaching7 m. The crown is spherical. The white flowers are about 1.5cm wide, and the fruits are a crimson red. The small ovate leaves turn a vibrant orange in the fall.

Distribution and habitat

''P.'' × ''eminens'' takes after ''P. fruticosa'' in preferring open, steppe-like habitat, although it also grows in

forest edge A woodland edge or forest edge is the transition zone (ecotone) from an area of woodland or forest to fields or other open spaces. Certain species of plants and animals are adapted to the forest edge, and these species are often more familiar to hu ...

s. In the wild it is chiefly found in central Europe, in the western part of the range of ''P. fruticosa'' and largely over-lapping and supplanting it there.

Cultivation

Canadian researchers have crossed the parent species and selected the offspring to create cultivars which are marketed as Mongolian cherry or dwarf sour cherry by commercial nurseries. A further backcross of ''P.cerasus'' with ''P.×eminens'' has yielded a cultivar dubbed 'SK Carmine Jewel', with follow-on cultivars 'Crimson Passion', 'Juliet' and 'Romeo', which produce cherries at the northernmost limits of viable ''Prunus'' production. These cultivars have a tidy spherical growth habit, are very cold hardy (to USDA Hardiness Zone 4a or better), and their high sugar content fruit makes good pies, jams and jellies. A cultivar named ''Prunus'' × ''eminens'' 'Umbraculifera', with a slightly weeping form when mature, is commercially available as an ornamental. Unlike the agricultural cultivars, 'Umbraculifera' is not a heavy fruit producer, but produces sufficient pollen to be useful for honey production.

Uses

Some tests have been conducted to assay its usefulness as a dwarfing rootstock for other ''Prunus'' species. The small size and spherical growth form of ''P.'' × ''eminens'' 'Umbraculifera', and its autumn finery and cold hardiness make it useful as a

street tree Urban forestry is the care and management of single trees and tree populations in urban settings for the purpose of improving the urban environment. Urban forestry involves both planning and management, including the programming of care and ...

. It does well in containers and on

green roof A green roof or living roof is a roof of a building that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. It may also include additional layers such as a root barrier and drainage ...

s. It is planted in cities from Sweden to Hungary and Ukraine. Commercial nurseries graft the compact spherical crowns to other ''Prunus'' stems to produce taller standard forms with a lollipop-like appeal.

Notes

References

{{DEFAULTSORT:Prunus eminens eminens Hybrid prunus Plants described in 1893 Flora of Middle Europe Interspecific plant hybrids Ornamental plant cultivars