The Genus Rosa
Based on fossil record Roses (Rosa species) appeared around 40 million years ago during the Eocene period.
Wild roses naturally occur through the temperate and subtropical zones of the northern hemisphere and over half the species are native to China. Roses are also native to Europe, North America, and Northwest Africa, reaching as far south as the tropical mountains of Ethiopia, Mexico and the Philippines. The tropics prevent their expansion as a native wild plant in equatorial regions or the southern hemisphere.
Roses are much loved but little studied. The last complete account of the genus was by J.G. Baker in Ellen Willmott’s The Genus Rosa in 1910-14, resulting today in an approximate accepted number of over 100 species (perhaps 150).
Underlying this taxonomic problem is the fact that many have been cultivated and hybridised for centuries with the belief now that many of the original “species” are more likely to be ancient hybrids of complex and disputed ancestry.
The Chinese cultivated roses both for ornament and medicine for some 2000 years — compared with the European roses they included species with longer flowering season, brighter coloured flowers. Double-flowered as well as repeat-flowering dwarf forms had been developed
The first introductions to the West in the late 18th century were based on Chinese cultivated roses (although thought to be species at that time). Today four Chinese cultivars are recognised as the first introductions to the West: ‘Slater’s Crimson’, ‘Parson’s Pink’, ‘Hume’s Blush’ and ‘Park’s Yellow’. They are all now recognised as decendants of just two species: Rosa chinensis and R. gigantea.
The introduction of these four cultivars revolutionised European rose-breeding and the mixed gene pool resulted in the thousands of wonderful ornamental rose cultivars we see today. |
