Climbing roses are varieties cultivated to produce long, flexible canes trained upward on supports like arbors, trellises, and walls. While these plants offer spectacular vertical displays, their exposed nature makes them susceptible to damage during cold winter months. Winterization protects the plant’s delicate tissues from harsh conditions, particularly freeze-thaw cycles and desiccation. Without adequate protection, canes may experience dieback, and the root crown and graft union risk permanent injury. Preparing the rose for winter ensures the survival of the plant, allowing it to regenerate vigorously and provide abundant flowering the following spring.
Preparing the Rose for Winter Dormancy
Winterizing a climbing rose begins weeks before the ground freezes, typically after the first light frost. This cold exposure signals the plant to slow growth and enter dormancy. To support this transition, cease applying high-nitrogen fertilizers by late summer or early fall. Continuing to feed the rose encourages soft, new growth that is highly vulnerable to frost damage and will not harden sufficiently before winter.
Reducing irrigation during this period also helps the canes “harden off.” Lower water availability signals the plant to reduce moisture content within its cells, increasing cold tolerance by lowering the freezing point of the cell sap. However, the plant should not be allowed to dry out completely, as dehydration makes it susceptible to desiccation during windy, dry winter conditions.
Sanitation around the base of the rose is a major step in winter preparation. All fallen leaves and spent debris must be meticulously removed from the soil surface surrounding the plant. This organic matter often harbors fungal spores, such as those responsible for black spot, and overwintering insect pests. Eliminating this debris reduces the likelihood of disease pressure while the plant is dormant.
Undertake a light, preparatory pruning to remove weak, thin, or crossing canes unlikely to survive the winter. Cut back any diseased or damaged wood to healthy tissue and dispose of it away from the garden. This step should not involve removing the main, structural canes, which are needed for spring growth.
Protecting the Root Crown and Graft Union
The most sensitive part of the climbing rose is the graft union—the swollen area where the desired rose variety joins the rootstock. Exposure to severe cold can cause the plant to die back completely to the rootstock, resulting in the loss of the cultivated variety. Protecting this point ensures the entire plant can regenerate, even if the upper canes are lost.
Protection begins by creating a protective mound directly over the root crown and graft union. Carefully pile dry soil or finely sifted compost 10 to 12 inches high around the base. This soil layer acts as the primary thermal buffer, preventing rapid fluctuations in ground temperature that cause damaging freeze-thaw cycles.
For further insulation in very cold climates, place a protective collar around the base of the mound. Secure hardware cloth or a wire cylinder, approximately 18 inches high and wide, around the base. Fill this cage with lightweight, insulating materials such as shredded leaves, clean straw, or pine needles.
These materials provide air pockets that trap heat and stabilize the soil temperature. Coarse materials are preferable to dense organic mulch, which retains excessive moisture and encourages rot. Apply the insulating material after the ground has frozen slightly to prevent nesting by pests.
Insulating and Securing the Canes
Once the base is protected, attention shifts to the long, exposed canes, which are susceptible to desiccation from cold, dry winter winds. The protection method depends on the rose’s age, cane flexibility, and the severity of the local climate. Older, woodier canes often cannot be safely bent without snapping, requiring a different approach.
Ground Burial (Minnesota Tip)
The most comprehensive method, often called the “Minnesota Tip,” involves physically detaching the canes from their support structure. This technique is reserved for colder regions where temperatures consistently drop far below freezing. The goal is to get the canes onto the ground, where the soil offers a consistent, warmer temperature.
Bend the detached canes slowly and gently toward the ground, moving them incrementally over several days if necessary to prevent breakage. Once the canes are lying flat, secure them with landscape staples or heavy wire hoops. Spread a thick layer of insulating material, such as straw or shredded leaves, over the entire length of the laid-down canes.
Place a protective layer of soil or heavy burlap over the insulation to hold it in place and provide additional protection from wind and moisture. Covering the canes completely shields them from drying winter winds and maintains a stable, warmer environment. This technique offers the highest survival rate for canes in extremely cold climates.
Upright Wrapping
For older, stiffer climbing roses that cannot be safely maneuvered to the ground, upright wrapping is the necessary alternative. This approach involves leaving the canes secured to their support structure and insulating them in place. The primary risk with this method is poor ventilation and potential moisture buildup.
Loosely wrap the individual canes or the entire bundle with burlap or specialized rose blankets. Ensure the material is not cinched too tightly, which could damage the tissue. The space between the canes and the wrapping material can be loosely filled with dried straw or pine boughs to enhance insulation.
Regardless of the method, ensuring adequate ventilation is necessary to prevent the canes from rotting. The protection material must be applied loosely enough to allow air circulation and prevent moisture accumulation. Trapped moisture, especially during warm spells, creates conditions conducive to mold and can cause more damage than the cold itself.