Plan to continue watering plants, particularly new ones, throughout the winter months if we go extended periods of time with no or very little rain. Trees and shrubs don’t require nearly as much water during the winter, but they should not be allowed to dry out. A plant weakened by the lack of water is more susceptible to cold damage.
Water is particularly important before a hard freeze. Use a garden hose to direct water to the base of the plant, and try not to wet the foliage.
Mulch your plants to conserve moisture and keep the roots warm. You might need to replenish the mulch on existing beds if it has scattered or decomposed. I usually do this after most of the leaves have fallen from the trees. A 3- to 5-inch layer of organic mulch, spread uniformly under the shrubbery should be sufficient. Pine straw, pine bark, or leaves are good organic mulches.
Protect the graft union of newly planted roses and fruit trees. The graft union of these plants is most sensitive to the cold. Before a hard freeze, mulch material can be mounded over the graft union of your roses to help keep the graft warm. The trunk of young fruit trees can be wrapped in special tree wrapping materials available from some garden centers.
Plant and construct windbreaks on the northwest side of the home. Most cold winter winds and sudden temperature changes come from the north and northwest. A wind barrier such as a fence, wall, or grouping of evergreen trees or shrubbery can help control both wind speed and direction. Windbreaks will reduce wind velocity for a distance about ten times their height. For example, a windbreak 30 feet high will protect an area extending as far as 300 feet downwind. Temporary windbreaks can be constructed from cardboard or plywood to protect individual trees or shrubs in exposed locations.
Sheets or blankets placed over annual flowers or tender shrubbery can help spare them from a mild freeze. Secure them to the ground with soil, bricks or rocks. Be certain the covering goes all the way to the ground so that heat radiating from the warmer ground can be captured and held under the covering during the night.