Winter protection is necessary for many gardeners, especially those cultivating less cold-tolerant varieties like Hybrid Teas or Floribundas. These measures shield the plant from damaging freeze-thaw cycles and harsh, desiccating winter winds. The goal is to maintain a consistently cold temperature around the bud union, ensuring deep and stable dormancy, rather than keeping the plant warm. Proper timing and application techniques significantly increase the rose bush’s chances of surviving the cold months and thriving in spring.
Pre-Frost Preparation and Timing
Preparation should begin only after the plants have entered dormancy, generally triggered by several nights of hard frost. Applying protection too early can trap warmth and moisture, encouraging tender growth that will be killed by the cold, or fostering fungal diseases and rodent infestation. Wait until the leaves have fallen naturally and temperatures have consistently dipped below freezing, but before the ground has frozen solid.
Before applying covering material, clear away all fallen leaves and debris from around the base of the rose bush to reduce overwintering fungal spores or pests. The canes should be watered deeply one last time before the soil freezes. Hydrated tissues are better equipped to withstand the stresses of freezing temperatures.
Pruning should be minimal, focusing only on reducing excessively tall canes that could be damaged by heavy snow or whipping winds. Cutting the canes back to approximately 24 to 30 inches is sufficient to prevent wind damage without removing material needed for spring growth. Tying the remaining canes loosely together with twine helps prevent movement that could loosen the soil around the crown once the covering is in place.
Choosing and Applying Protective Materials
The most important step is insulating the bud union, the thickened area where the rose was grafted onto the rootstock. This area is highly susceptible to cold damage and must be covered with a mound of material at least 10 to 12 inches high. The mounding material should be brought in from another location, as scraping soil from the plant base exposes shallow feeder roots to the cold.
Clean, well-draining materials such as shredded leaves, straw, compost, or fresh soil are suitable for mounding. Avoid using manure or fertilizer-enriched soil, which could stimulate unwanted late-season growth, and wet materials like grass clippings, which can promote rot. The mounded material should be settled lightly with water and can be contained using a wire cage or a specialized rose collar to prevent erosion.
For the exposed canes above the mound, additional measures prevent desiccation from winter wind and sun scald. Burlap wrap is a frequently used option because its woven structure is breathable, protecting the canes while allowing air circulation to reduce moisture buildup. Canes can be wrapped directly with burlap or contained within a wire cylinder filled with a loose insulating material like straw or pine boughs.
Another option for cane protection involves specialized rose cones, placed over the plant after the canes have been trimmed to fit. If using cones, ensure they have ventilation holes near the top and bottom to prevent overheating and condensation on sunny days. Non-breathable materials like plastic sheeting or tarps should never be used, as they trap moisture and heat, which can be detrimental to the dormant plant.
Uncovering Roses in Spring
The removal of winter protection must be a gradual process to allow the rose to acclimate to ambient conditions. The process typically begins in early spring, once the threat of sustained hard frost has largely passed and the ground has thawed. Removing the protective layers on a cool, overcast day is best, as it reduces the risk of sun scald on any tender, pale new growth.
The first step is to remove any covers from the canes, such as cones, burlap, or straw-filled cylinders. If rose cones were used, remove them during warm spells to prevent excessive heat buildup, but keep them nearby in case of a sudden temperature drop. After removing the cane protection, wait several weeks before disturbing the mound of soil or mulch at the plant’s base.
The mound should be pulled back slowly, allowing the plant’s bud union to gradually adjust to the cooler air temperatures. This slow acclimation helps prevent the plant from breaking dormancy too quickly, which leaves new shoots vulnerable to a late-season frost. Once the protective layers are fully removed, any canes that appear blackened or dried out from winter damage should be pruned back to healthy, green wood.