How Many Species of Roses Are There?

Estimate Based on Chloroplast DNA Sequences

• According to scientists who studied the deoxyribonucleic acid (DNA) present inside the green, chlorophyll-containing structures called chloroplasts within rose leaves, about 190 roses species exist. Based on those findings plus floral and plant structures, botanists concluded that roses originated in Europe and Asia, and that the presence of wild rose species in North America is the result of several separate introductions from the Old World. The center of diversity for roses is in western China, and no native roses exist in the Southern Hemisphere.

Conservative Estimates

• Authors Kim E. Hummer and Jules Janick, in their paper on Rosaceae posted on the Purdue University NewCrop website, give the opinion that more than 100 species of roses exist and range throughout the Northern Hemisphere's temperate regions, from the Arctic to the subtropics. Scientists at the U.S. Government's Integrated Taxonomic Information System compiled a report on world rose taxonomy that lists 101 species. These figures don't include cultivated roses.

Modern Rose Ancestors

• Experts agree that of all the wild species of roses, only seven to 10 of them were involved in the production of modern cultivated roses. Ancestral species roses came mostly from China, India, Europe, Northern Africa and Central Asia. Over the centuries, gardeners in the two major rose-growing areas of the world, Europe and Asia, transformed once-wild roses into garden subjects, selecting and hybridizing them for improved flower color, form and fragrance as well as their ability to be used in gardens. From ancient times, roses were valued as sources of essential oils to use in perfume and cooking, as cut flowers and as landscaping plants.

Origin of Modern Roses

• By the 1700s, European roses were divided into five basic categories, collectively called the Old European roses. In the late 1700s, roses from China became available, and the China group of roses crossed with the Old European roses to give rise to new rose classes. Two of them, hybrid perpetuals and tea roses, were bred together to produce modern hybrid tea roses (Rosa x hybrida), which are hardy in USDA zones 6b through 10b, depending on the variety or cultivar. "La France" (Rosa "La France"), introduced in 1867, was the first hybrid tea. It is hardy in USDA zones 4 through 9. Hybridizing has continued to create current rose classes, such as Grandiflora, Floribunda, Miniature and Polyantha roses. About 13,000 named cultivated roses exist, according to estimates.