Most modern hybrid roses need some winter protection because their parents are of subtropical origin.
If roses have grown excessively, they may be subject to snow and wind damage. In November, prune all tall plants by one-third of their height. Otherwise, mid-April is best.
In December, remove all leaves and debris from the ground. This will help prevent the spread of some diseases. When the night temperatures drop to 20 degrees Fahrenheit for several days, mound soil over the rose crown. The soil should be eight to ten inches deep. Bring soil in from other parts of the Garden to avoid disturbing the roots of the plant being covered.
Other suitable mulching materials include pine needles, boughs, leaves, rotted manure or sawdust. Mulching is very important because it keeps the soil at a uniform temperature, reducing the possibility of early growth that might be injured by frost. The mulch should be removed gradually in the spring after the danger of hard frost has passed. Climbing roses can benefit from being completely covered with burlap during the winter to prevent desiccation from wind.
Selecting an appropriate rose for this region, choosing the proper planting site and following good cultural practices will minimize insect and disease problems.
For more information, see the following Colorado State Extension fact sheet(s).