Plant Hardiness and Its Significance to Your Trees This Winter

Winter is almost here. To tolerate the colder temperatures, you’re bundled up or snuggled beneath a blanket within the comfort of your home. But how do your trees face the next few months of ice, snow, and extreme cold weather?

Although freezing temperatures, snow, and sleet have greeted some of us already, the winter season has more frigid weather in store for us which greatly affects our landscape trees and shrubs. The health and vitality of your trees are extremely important in withstanding such conditions and will help you determine which best practices should be done to address proper care this season. Read below for an explanation of plant hardiness:

What exactly does plant hardiness mean?

When trees sense a decrease in sunlight and temperatures as the winter season approaches, they begin to slow shoot and bud growth and store energy in the roots to prepare for spring flush. This is a process in which cells in the bark begin to harden. This insulates the tree, preventing it from freezing. The more hardening that occurs in a tree’s bark, the more cold-hardy it is.

What is the USDA Plant Hardiness Zone Map?

The USDA Plant Hardiness Zone Map is a guide that gardeners, growers, and planters use to determine how likely any particular species is to cope in different regions within the U.S. Each species is assigned a number or numbers that pertain to the zone(s) in which it may thrive.

Why is the USDA Plant Hardiness Zone Map important to plant survival?

“Most plant material native to the south will not react appropriately or timely to the winter conditions in the north,” says Jim Zwack, VP of the Davey Institute. For example, freezing temperatures in the north could easily harm non-native plants. Seek native plants from local, well-established nurseries when choosing specimens to bring home and plant in your landscape. Tree problems also may occur when a specimen hasn’t yet adapted or cannot adapt to the environment in which it is planted.

What about coniferous trees? Why do they stay green all winter long?

Evergreen trees have narrow needles that help conserve water and energy during winter. This allows conifers to maintain the green pigment chlorophyll in their needles throughout the year, unlike deciduous trees that break down chlorophyll and mobilize those resources during the fall color period.  A combination of frozen soils with mild air temperatures, however, can lead to the browning or “burning” of evergreens.

If you need help choosing the best trees and shrubs for your landscape, contact your local Davey professionally trained arborist for a free consultation.