The days are getting longer; the sun, a little stronger; and your green thumb is starting to twitch. What's a gardener to do when the ground is frozen and getting to the potting shed seems like a walk across the tundra? Remember that while everything above the ground is hibernating, everything below the ground is teaming with activity. For instance, your compost pile: Continue to add your kitchen refuse to the compost pile, and when the inevitable winter thaw arrives, take advantage of the warmer weather and turn your compost pile.
Winter warming periods pose problems for perennials, which can heave out of the ground. It's a good time to look for those plants and get some mulch or compost around them to protect their exposed roots from the inevitable return of freezing temperatures. Evergreens are also susceptible to the ups and downs of winter temps, so keep an eye out for winter burn and apply antidesiccants when temperatures cooperate. Remember, even in late February, the mid-day sun is strong enough to give you sunburn, and as it shines on leaves it heats them up just as it does your skin.
At this time of year, the air is typically very dry, so water can quickly evaporate out of stomata into the parched atmosphere. Normally, a tree or shrub will draw water from the earth to replace what has been lost through its leaves, but if the ground is frozen, replenishment is impossible. With no water coming from the roots, the leaves and even twigs and larger branches simply dry up. Often desiccation injury that happens in February doesn't appear until later, when temperatures warm to reveal injured or dead stems.
One sure sign of winter burn is damage that occurs to plant areas above the snow line. Snow may cause problems for leaves higher up, but it shields the lowest ones quite effectively. Note that newly planted shrubs with underdeveloped root systems are particularly susceptible.
While winter is a great time to study the shape and structure of woody plants, it is not the best time to prune. Fresh cuts on plants can lead to problems during winter warm spells. Since the fresh wound does not have time to heal, the quick rise in temperature can lead to "bleeding," which may invite insects and disease. It is also not the time to make decisions on whether a winter-damaged branch will, or will not, return in the spring. Plants are very resilient and giving them until mid-May to make a recovery can prevent an unnecessary cut.
A great activity for the impatient winter gardener is to get your tools in shape. The more time you spend now preparing for the spring, the more time you will have to actually garden.
Sharpen all tools, including your shovels, hoes and trowels, with a blade. Use a flat file and move in the same direction (away from you) as you sharpen. A crisp sharp edge on your digging implements will prevent at least one blister. Take apart your pruning and hedge shears, lightly scrub them with steel wool, and lubricate all moving parts. Don't forget the handles, especially wooden ones. Sanding wooden handles and applying a fresh coat of linseed oil will help prevent excessive drying and splintering.