The United States Department of Agriculture has created a map of numbered plant hardiness zones, and these zones represent areas of the United States having similar average low temperatures in winter. The lower the zone number, the harsher the winter. Roses typically grow in warm climates, and flower in the summer months, but some roses can grow in the hot tropical climate found in Florida, while others can grow in hardiness zones as low as 2, which have winter temperatures that drop as low as -50 degrees Fahrenheit.
The south of Florida has a tropical climate, enjoying long, hot humid summers. A number of rose species grow well in this climate, and are able to tolerate periods of drought that other other roses do not tolerate. Most of the roses that grow well in this climate originated in China, and came to the United States via Europe. The most common China rose grown in the hot dry conditions prevailing in south and central Florida is Old Blush, otherwise known as Parson's Pink China. Another variety of roses that flourish in hot dry climates are Noisettes, named after the Charleston nursery owner Philip Noisette who first cultivated these roses from seeds, and Bermuda roses, which come from the Atlantic island of Bermuda.
Wind And Low Humidity
The climate of Colorado is dry, particularly in the west of the state. Winters are dry and freezing, with much of Colorado rated as hardiness zones 4 or 5. This means that winter temperatures can get as low as -30 degrees Fahrenheit. Springtime can be windy. Some climbing roses grow well in this climate, and although you should plant them where they will not be fully exposed to the wind, whenever possible, many climbing roses will still grow and flower. The roses that grow best in the Colorado climate are Old Garden Roses and Canadian Explorer roses.
While roses do not bloom in winter, they are perennial shrubs that must survive the winter months so that they can bloom again the following year. Harsh winter frosts will kill most rose varieties, but some can withstand winters in hardiness zones as low as zone 2, where winter temperatures can get as low as -45 degrees Fahrenheit. Roses that are able to survive zone 2 include Blanc Double de Courbert, which produce white double-flowers, Assinboine, which produces medium-sized red blooms and Dart's Dash, a rose producing purple and red double-flowering blooms.
Temperate climates, such as those found in England, and much of the northern Mediterranean, and those found in the maritime parts of northern California and southern Oregon, are good for growing most rose species. Most of the modern roses found around the world originate from breeding done in continental Europe, England and the northern Mediterranean, using specimens imported from Asia, and especially from China. Most English and European garden roses, cultivated for temperate climate growth, do not do well in climates where the winters are harsh.