Wind-driven air and too little precipitation are common wintertime side effects that can damage drought-sensitive trees, lawns and shrubs.
You can help remedy that by watering when temperatures are still above freezing and before the ground hardens. Adding mulch also insulates plants, enriches topsoil and provides cover for native pollinators.
“Plants that have an ample supply of moisture going into winter survive better,” said Dennis Patton, a horticulturist with Kansas State University Research and Extension. “The ones that suffer the most are the evergreens because they have foliage that dries out. They experience more browning.”
Plants should be cared for in much the same way you care for humans, Patton said. “With the proper diet and exercise, people are quicker to fend off diseases,” he said. “The same goes for plants. They’re able to tolerate more stress.”
Give landscape and foundation plants a last, healthy watering using sprinklers and soaking hoses before the onset of winter’s deep chill. Most plants go dormant but still crave moisture, which poses practical problems for watering.
People living in severe climates should remove hoses and hose attachments to allow faucets to properly drain through winter, Patton said.
“I try to take advantage of those periods when the soil warms and you can water again,” Patton said. “If you have an older hose or a short hose that you can leave out in winter, you can connect and disconnect. Or use a 5-gallon bucket to slowly add water.”
Soak the soil to a depth of 6 to 8 inches. “That degree of saturation should provide enough moisture to reach most of the roots,” Patton said. “Use a rain gauge or a trowel to measure your water output.”
Newly planted trees and shrubs are more susceptible to tissue damage than established plants, according to James Klett, a professor with the College of Agriculture Sciences at Colorado State University.
“Trees generally take one year to establish for each inch of trunk diameter,” Klett says in a fact sheet. “Bare root plants require longer to establish than container plants. Perennials planted late in the fall will not establish as quickly as those planted in spring.”
Mulching combined with watering helps considerably to avert winterkill.
“There are two primary seasons for mulching,” Patton said. “You put it down around plants in spring through summer to hold moisture and prevent weeds,” he said.
“But winter mulching covers the plants. That keeps plants cooler and protects them from warm winter days.”
Just as we aren’t used to the cold after some warm days, “neither are plants,” Patton said. “Winter mulches keep them insulated from those fake spring-like days we sometimes get.”
And what about those end-of-season yard cleanups? Do they help plants survive winter?
“Forget about it,” Patton said. “Letting things go natural into winter is an emerging trend. Sometimes people leave plant material for wintertime interest or where it catches leaves and snow for insulation and prevents erosion.