Winterizing roses is a proactive garden practice that ensures the survival of the plant’s crown and roots through the coldest months, safeguarding its health for the following season. Roses, like many deciduous plants, require a period of dormancy, a necessary rest cycle that allows them to conserve energy and prepare for vigorous spring growth. Proper care involves a series of carefully timed steps, beginning in the late fall, to guide the plant into its winter slumber and protect it from temperature extremes and desiccation. This preparation is particularly important for less cold-tolerant varieties, such as hybrid teas, floribundas, and grandifloras, which are susceptible to damage at the graft union.
Preparing Roses for Dormancy
Preparation for winter begins in late summer to signal the plant that it should cease active growth. The most immediate step is to stop all nitrogen-heavy fertilization approximately six to eight weeks before the average date of the first expected hard frost. Continuing to feed the rose encourages tender new shoots that lack the rigidity to survive freezing temperatures. The focus shifts from growth stimulation to maturation, allowing existing canes to “harden off” before dormancy begins.
As the days shorten and temperatures drop, gradually reduce watering frequency, though the plant should not be allowed to dry out completely. Adequate moisture in the roots is important for surviving the drying effects of winter winds and frozen ground. Fall is also the time for thorough sanitation, which involves cleaning up all fallen leaves and debris around the base of the plant to remove overwintering fungal spores.
Finally, a light, functional pruning, or “heading back,” should be performed to reduce the height of tall canes to about two to three feet. This measure is preventative, minimizing the leverage of winter winds that can cause the canes to whip, rock the root ball, and loosen the plant in the soil.
Protecting Roses from Extreme Cold
Physical protection techniques are applied once the rose has entered full dormancy, signaled by a few consecutive hard freezes or when the leaves have fully dropped. The primary method for protecting in-ground roses is “hilling” or “banking,” which focuses on insulating the vulnerable graft union at the base of the plant. A mound of loose material, ideally fresh soil, compost, or shredded leaves, is piled around the base of the plant to a height of approximately 10 to 12 inches.
This deep layer of insulation is applied after the ground has frozen. Applying it too early can trap warmth and encourage premature growth that subsequent cold snaps will kill. The goal of this mounding is not to keep the rose warm but to keep it consistently cold, preventing damaging freeze-thaw cycles that can heave the plant out of the soil and damage the crown. For added protection in colder climates, a wire cage or specialized rose collar can be placed around the plant and filled with insulating materials such as dry straw or pine needles.
Protecting the canes themselves from windburn and desiccation can be achieved by loosely wrapping the bundled canes in burlap. This fabric acts as a windbreak while allowing air circulation to prevent moisture buildup and rot.
Managing Container and Climbing Varieties
Roses grown in containers require a different strategy because their roots are fully exposed to air temperature, unlike those in the insulating earth. Once dormant, container roses should be moved to a protected, unheated space, such as a garage, shed, or cold frame, where temperatures remain cool but consistently above freezing. This space must be unheated, as excessive warmth can trick the plant into breaking dormancy prematurely, leading to weak growth that will not survive.
During the winter rest, potted roses require minimal, yet regular, moisture to prevent the roots from drying out, a condition known as desiccation. The soil should be checked every two to three weeks and lightly watered, providing just enough to keep the medium barely moist without becoming waterlogged, which can lead to root rot.
For climbing roses, which are often less cane-hardy, the most secure method in very cold regions involves detaching the canes from their support structure. The canes should be carefully bundled together and then gently bent down to the ground, where they can be covered with a thick layer of mulch or soil, providing insulation.
Transitioning Roses Out of Winter
The final stage of winter care involves safely transitioning the roses in the spring. The removal of protective coverings, such as burlap wraps and rose cones, should begin when the danger of a hard, sustained freeze has passed, generally when nighttime temperatures are consistently above freezing. This process should be gradual, starting with the outer layers of insulation, to prevent the canes from experiencing shock or sun scald from sudden exposure to bright sunlight.
The heavy soil or mulch mounds around the crown should be gradually pulled back over a period of a few weeks, allowing the graft union to acclimate to the ambient air temperature. Once the protective materials are removed, the main structural pruning can take place, timed to occur when the leaf buds are visibly swelling. During this pruning, all dead, damaged, or dark-colored canes are removed, and the remaining healthy wood is cut back to an outward-facing bud to encourage an open growth habit.
Fertilization should be cautiously reintroduced once new growth is clearly visible. This is often done with a slow-release formula to provide the necessary nutrients.