Clean up plant debris in the area surrounding the roses to prevent diseases from overwintering. Mound soil or compost eight to ten inches high around each rose plant. Bring in new soil for this rather than displacing soil from the area around the roses to avoid damaging the roots and exposing them to the cold.
Once the ground has frozen, add a 4-inch layer of straw, leaves, wood chips or other mulch over the mound and cover with a layer of soil to hold it in place. This will help protect the plants from the cold but also prevent early budding during warm winter and early spring days. As the mulch settles during winter you may need to add more.
Prune canes to 36-inches and remove weak or thin canes. Tie the remaining canes together loosely to keep them secure during windy weather. If the canes are allowed to whip in the wind it can cause damage to the crown and disturb the soil.
When the ground thaws in the spring remove the mulch and soil from the base of the plant to return the soil level to normal. (Cynthia Domenghini)