Most gardeners don’t think about burying their roses, but that’s essentially what they should do to protect them from winter’s extremes. Similar to hibernation in animals, roses and other woody plants go through a dormant (rest) period in the winter.
The first step to winterizing roses is to keep them healthy through the growing season. Gardeners should protect roses from insect and disease damage and maintain adequate fertility and moisture.
After several killing freezes in late fall, plants become dormant; this is the time to put on the winter protection.
Pick up and remove debris, such as leaves and dead stems on and around the plants to prevent diseases from overwintering. If the soil is dry, give the soil a thorough soaking. Plants underneath overhangs of buildings often are very dry, even during wet seasons.
The most foolproof method of protection is to mound the soil up around the plant to protect the graft union. A 12-inch-high mound–approximately 5 gallons–of soil provides excellent protection. A soil mound will also prevent rabbits from feeding on the stems.
Prepare the plant by tying the canes up with twine, not only to prevent excessive wind whipping but also to make mounding easier as well. Begin by tying twine to a lower branch base, and wind the twine up the plant in a spiral fashion. Save pruning chores until late winter or early spring. Branches cut in fall tend to die back from the cut through winter weather.
Dig the soil for the mound from an area away from the roses, so as not to damage their roots. For further protection, pile additional mulch, such as straw or chopped leaves, on top of the soil mound.
Commercially available rose cones have been used with varying success. Some soil mounding is still advisable–about 6-8 inches to protect the graft union and to anchor the cone. Plants must be pruned to fit under the cone. And it’s important to cut slits in the top of the cones to provide air ventilation, because excessive moisture buildup encourages fungus growth. A heavy rock or brick placed on top of the cone will help secure it in place.
In early spring, both soil mounds and cones must be removed as soon as plants begin new growth. Don’t forget to remove the twine, and be careful not to injure old canes or new shoot growth. Soil from the mounds should be placed in another area.