Plants don't need as much care in winter as they do in summer, but it's important not to neglect watering your plants over the winter. Some ice or wind damage is unavoidable, but a lot of cold weather damage to plants' cells is caused by dehydration. In many regions, normal winter precipitation is enough for plants because their cold weather watering needs are considerably less. However, making sure your plants have adequate hydration is the best way to protect them harsh weather.
Water your garden thoroughly in the fall, and deeply water newly planted saplings and shrubs. Plan to give the garden a deep watering every two to three weeks until the first frost.
Mulch your garden with leaves and compost in the fall after pulling spent annuals and cutting back perennials. Mulch protects your topsoil and helps it retain water. It also nourishes roots and keeps them warm. Spread at least an inch of mulch over the ground. Pile up some extra mulch around any new saplings or plants that have been planted within the last year.
Prepare for sudden fall frosts by checking your local weather report. Watering your plants before a frost will protect them from damage caused by freezing. The roots need a chance to absorb the water before it freezes, so try to soak them at least 24 hours before the frost.
Avoid getting water on the plants' stems and leaves when you water in the winter. Ice sitting on foliage can kill it or cause it to break off. Water woody plants like shrubs and saplings away from the trunk because ice can damage the bark.
Water plants during the winter only after long dry spells of two weeks or more. Plants are inactive during the winter so they don't need much water, but if the soil completely dries out they risk damage from wind and dehydration.
Water your garden even when the ground is frozen during a long winter dry spell. Watering helps aerate the soil and warm the roots, and plants can't get enough moisture from the soil when it's frozen. Do the watering mid-day to give the plants a chance to absorb the moisture before night temperatures freeze the water.
Watch sunny parts of your garden for shallow-rooted plants that have heaved, or raised out of the soil due to repeated freezing and thawing. If you see a plant has heaved, push it back into the soil as soon as possible and give it some extra mulch to keep it shaded and prevent the soil from thawing.