Q: It’s winter. I can sit back, relax, and ignore my garden—right?
A: Not quite. The sky is bright blue, the sun is shining, the predicted high is well above freezing, and it’s been like that for months. Sounds like perfect weather—but not if you’re a plant. In fact, if you listen, you can hear their cry for water. Everything is so dry! Desiccating winds have drained the last vestiges of moisture from exposed leaves and branches, and even the so-called evergreens are shriveled.
While the Midwest and Northeast get plenty of snow cover (like the photo to the left), and the Northwest gets rain all winter, Colorado gets neither. When the weather continues this dry and windy, it’s up to the gardener to keep the soil damp. It is essential to provide enough water for our plants to replace what is lost to evaporation.
Supplemental irrigation is important for ornamental grasses and perennials—the top growth might be brown and crispy, but the roots are very much alive. It’s important for deciduous trees and shrubs. It’s particularly critical for dormant lawns. And it’s a matter or life and death to any plants that keep their leaves all winter. In fact, our dry winters are a major reason evergreen shrubs that do well in other parts of the country do not survive Colorado.
At this time of year, the ground is mostly frozen, so winter watering is a bit tricky. For one, we’ve drained our sprinklers and drip systems, and the hoses are coiled in the garage. Watering means hauling those heavy hoses out to the garden, hooking them up, and then draining them and putting them away again when we’re done. The alternative is to lug a heavy watering can—not a practical solution for most yards.
Another problem is the frozen ground we’re dealing with. Dumping water on top of icy dirt accomplishes little beyond creating a skating rink. We have to time our irrigation carefully, waiting for a warm day and using the mid-day thaw to get some water into the soil. Use a screwdriver or other poky tool to check and make sure the water is actually soaking in. Ideally, you want to dampen the entire root zone—one to two feet deep.
Gardeners can reduce the need for winter watering by applying a generous layer—three to four inches—of mulch to their planting beds. (Unfortunately, we can’t mulch our lawns.) Mulch replaces snow as winter insulation, both keeping existing moisture in the ground, and mitigating the daily cycle of freezing and thawing that damages plant roots. Most shrubs appreciate a layer of organic matter such as shredded bark (recommended in windy areas), straw, shredded leaves, etc., Some natives prefer pea gravel, which mimics their natural habitat. Be sure to check under the mulch so see how dry things are. Mulch alone won’t completely eliminate the need to water.
Although it’s a hassle, winter watering is worth our time and effort. We have a lot invested in our lawns and gardens. Grass that dries out now will be dead come spring. Who wants to replace a lawn every year? Buying new shrubs and trees is not only expensive, but frustrating—it takes many summers for woody plants to reach maturity in our short growing season. Even if the plants don’t die completely, leaves can be burned and branches can experience considerable die-back (like the tree above), damaging both appearance and health.
It’s lovely not to worry about shoveling driveways, slipping on sidewalks, or driving on ice. On the other hand, our gardens really need some winter white stuff. Maybe skiers aren’t the only ones who need to be praying for snow.
Article and photos by Leslie Holzmann, Colorado Master Gardener.