What your garden is up to in winter

December 30, 2013

The garden may have dimmed for the winter, but it hasn’t turned off entirely.

Notice the green of evergreen needles. It shows that those plants still have chlorophyll for photosynthesis. All winter, they keep capturing energy to create food whenever there’s a sunny day and it’s not too cold. They are making food at a much lower rate than they do in spring and summer, but they’re still in business.

Even trees and shrubs with bare branches and fallen leaves are only sleeping. In the fall, they packed their root systems with stored energy in the form of starch and sugar. That stored food will give them a jump-start in spring until they can unfurl enough leaves to restart their own food factories.

Look closely at most trees and shrubs in winter and you will see buds at the tips of twigs. Each is already packed with a leaf or flower, all folded up. When the soil thaws and water starts flowing in spring, it will make the tissues swell so the buds open and the blooms and leaves unfold.

There’s life beneath the snow too. Snow is actually a good insulator, protecting against bitter cold and biting winds. Plants that would die if they dried out in the wind—such as bulb foliage that sprouted in fall—can stay safe and green beneath a layer of snow. Small animals, such as voles, burrow beneath the snow to stay invisible to predator such as hawks. They feed on grasses and sometimes on the vulnerable thin bark of young trees and shrubs.

Many animals are hibernating, tucked away in burrows or in the hollows of tree trunks, but not squirrels. They stay active all winter, foraging for stashed-away nuts as well as crocus bulbs. When it’s cold, squirrels huddle together for warmth in treetop nests of twigs and leaves called dreys.

Meanwhile, seeds lie in the soil waiting for the right conditions to sprout. Most need a particular combination of temperature, sunlight and moisture, and they can wait for years until the perfect spring. Seeds of plants that evolved in areas with cold winters often won’t sprout unless they’ve been chilled for a certain period.

To learn what you can do in winter to help your garden, consult the Plant Clinic.