|How should I prepare my roses for winter? Should I prune them back and cover them?|
|Since you didn't mention what kind of roses you're growing, I'll give the basic rundown on common types.
If you have individual rose bushes, cut canes back to 2 to 3 feet tall AFTER THEY'RE DORMANT. If the stems have turned purplish, they're dormant. If you prune roses before they've developed dormancy, it can reverse the process, and they'll likely be more succeptible to cold damage. Cover the crown with a 1-foot deep layer of bark mulch. This will protect the crown and allow air to circulate; soil, leaves and grass clippings tend to hold too much water which can cause rot. Then wrap the canes with burlap to protect them from drying winds.
Another method is to use purchased rose cones. Be sure to anchor them well so they won't blow away. These cost more, and I'm not sure if, they provide any better protection than the first method.
Hedge (shrub) roses tend to be hardy, and need little care beyond annual early spring pruning, and topdressing with compost.
Climbing roses vary in their hardiness. Large-flowered climbing and rambling roses are the hardiest, and require that their crowns be buried in 1-2 feet of mulch. Climbing 'sports' are very tender, and require uprooting and winter 'burial' of the entire plant.