snow damage on tree
Updated: August 26, 2021

Winter damage can occur on many plants. A rapid temperature drop following a mid-winter thaw can cause bark splitting. Dead twigs and branches in the spring may be the result of ice and snow damage from the winter. 

Ice and snow damage

  • Symptoms include bent or broken branches from the heavyweight of the ice or snow.
  • Heavy snow can be gently knocked from branches, but branches that are iced over may actually be more brittle and suffer further damage if removal is attempted.
  • Wind during ice storms will cause the most damage.
  • White pines in our area are especially prone to winter ice and wind damage.

    Winter color of evergreens 

    boxwood branches turn yellow and brown - winter damage symptoms on boxwood

    Winter damage symptoms on boxwood

    • Symptoms of winter damage can include a change from the normal green color to gray, yellow, blue, purple, bluish-green, brown, and bronze leaves or needles.
      • Examples of plants that are often damaged by extreme winter weather include
          1) Japanese cedar (Cryptomeria) turn bronze
          2) Yew (Taxus buccata) turn brown
          3) Eastern red cedar (Juniperus virginiana) turn brown
          4) Arborvitae (Thuja spp.) turn brown
          5) Creeping juniper (Juniperus horizontalis) turn purple
          6) White pines (Pinus strobus) turn yellow
          7) Boxwood (Buxus spp.) turn yellow-orange
    • Some evergreens such as Leyland cypress and spruce usually don’t change color. Dieback in Leyland cypress can occur under extreme winter temperature fluctuations.
    winter damage on leyland cypress

    Severe winter damage on Leyland cypress. Photo: David L. Clement

    • Causes of  ‘winter color’ can include low temperatures and drought stress. Often, the foliage colors will revert back to normal when springtime temperatures return to normal.

    Leaf scorch

    • Damage is most severe on shallow-rooted broadleaved evergreens such as azalea, rhododendron, holly, cherry laurel, boxwood, mountain laurel, or those at their northern limit for winter hardiness (Magnolia grandiflora, Aucuba japonica, Camellia spp. and others).
    • The injury occurs on dry, windy, warm, or sunny winter days when the ground is frozen. Plants are unable to move water from frozen soil to replace water lost from the leaves.
    • Leaves curl and droop, then brown from the tips and margins, giving the leaves a scorched appearance. In many cases, damage occurs during the winter months but symptoms appear in the spring as the plant begins to emerge from the winter dormant period and move into the spring growth phase.
    • Sometimes newly planted white pine and spruce can suffer needle scorch during their first season from limited root systems.
    • Needled evergreens in exposed conditions such as along roadsides and parking lots can suffer needle scorch.
    • Most damage is during the winter but in some cases, symptoms can occur during the spring as new growth appears.
    • Hardy gardenia shrub with winter scorch

      winter scorch on hardy gardenia
    • Evergreen magnolia leaves with winter scorch

      Magnolia foliage with winter scorch

    Salt damage

    • Heavy accumulations of de-icing salts can cause leaf scorch similar to winter damage and may kill buds and branch terminals.
    • Damage is caused by desiccation (extreme dryness) of the more tender tissue in buds and new growth.
    • Salt can also accumulate in the soil and cause root death from desiccation of root tissue.
    • Deicing salt runoff from one sidewalk or parking lot may not cause problems, but the combined effect from numerous such events raises the harmful concentrations of salt in adjacent soil and bodies of water.
    • Salt damage on evergreen juniper shrubs

      salt damage on juniper
    • Salt damage on evergreen yew shrubs

      salt damage on yew

    Freeze blasted blooms and new growth damage

    New growth damage

    • Warm temperatures in protected areas in February and March may stimulate buds, flowers, or shoots into growth too early.
    • Subsequent cold weather and frosts will kill young buds and tender new growth resulting in fewer flowers and later leaf development.
    • Frozen tissue damage frequently appears as blackened buds and leaves that may also drop off.
    • Pruning out remaining bare branches will help stimulate new growth later in the spring. 

    Blasted or damaged blooms

    • This damage results when flower buds swell and then freeze during cold snaps or late frosts. Star magnolia and lilac flowers frequently suffer from this type of injury.
    • The damaged buds and leaves usually drop off. Prune remaining bare branches if new growth does not emerge as spring progresses.
    • Freeze or frost damage on new growth of shrub

      Freeze or frost damage on new growth
    • Star magnolia flowers damaged by a late season freeze

      freeze damage on magnolia flowers

    Frost cracks and sunscald

    • Even hardy trees may develop sunscald or frost cracks.
    • Occur when temperature fluctuations are extreme. Water in the cells of the tree trunk freezes and moves out of the cells, causing the wood to shrink.
    • Tree bark warmed by the sun in winter can reach a temperature as much as 18 degrees warmer than the air temperature.
    • When clouds shade the bark or temperatures drop quickly at nightfall, the bark and cambium layer beneath is damaged. This type of freeze damage is called sunscald.
    • Tension between the frozen and unfrozen layers of wood is so great that the wood separates, causing a crack.
    • The crack can form suddenly and is often combined with a loud cracking sound.
    • When temperatures warm, the wood absorbs moisture and the crack closes.
    • Frost cracks can reopen and enlarge in subsequent winters and may extend to the center of the tree.
    • Damage to tree trunks in most likely on the south and west sides of the tree where the sun is strongest.
    • Frost cracks may begin in previously wounded or pruned areas.
    • Proper pruning and avoidance of injury may help to prevent some frost cracks.
    • Tree species prone to frost cracking (those with thin or smooth bark) may benefit from applying white latex paint to the tree trunk. The light color reflects light and helps to reduce temperature fluctuations.
    • The following species are more likely to develop frost cracks: apple, beech, crabapple, elm, goldenrain tree, horse chestnut, linden, London plane, maple, oak, walnut, and willow.

    Normal growth cracks

    • Occasionally growth cracks form in the tree trunk as a normal part of trunk development.
    • Growth cracks usually appear when the tree is growing rapidly during periods of abundant rainfall.
    • The bark splits longitudinally when cells in the cambium layer (the conducting tissue just under the bark of the tree) expand more rapidly than the bark can expand.
    • The tissue inside the crack looks like developing bark (smoother and lighter in color).
    • As growth continues, bark covers the crack and no permanent damage occurs.
    • Growth cracks can be differentiated from frost cracks or cankers because there is no heartwood visible, and no decay or oozing from the crack.
    • Frost and winter injury, James Solomon, USDA Forest Service, Bugwood.org

      frost crack on tree trunk
    • Sunscald damage, Joseph OBrien, USDA Forest Service, Bugwood.org

      sunscald damage on tree trunk

    Management

    • Cultural practices that conserve soil moisture, prevent root damage, and promote “hardening off” prior to winter will reduce winter damage.
    • Avoid fertilization or pruning in late summer, which stimulates late season growth that does not have time to “harden off” properly and is much more susceptible to winter injury.
    • When watering in the fall, soak the soil several inches deep, and then allow it to dry between waterings. This encourages deeper rooting. Avoid frequent shallow sprinklings, which encourage surface roots that are easily injured by drought and cold.
    • Freshwater sprays on foliage and deep watering in early spring will also help wash deicing salts from the leaves or needles and flush salts through the root zone faster to help reduce desiccation damage.
    • The use of mulches conserves soil moisture and prevents temperature fluctuations. Mulches also keep the soil cold in early spring, which helps to reduce premature bud break.
    • Wait until the plant puts out new growth in the spring and assess the damage.
    • Typically, damaged leaves fall off or are masked by new growth. Severely damaged shrubs may benefit from pruning. Prune to remove dead, damaged or broken branches and to stimulate new growth.