WSU Extension

Hortsense

Common Cultural : Winter injury
(revision date: 4/30/2013)


Biology
Winter injury includes a myriad of plant damage and symptoms, including death of stems and buds, frozen roots, sunscald and windscald of leaves and bark, bark splitting, leaf droop and roll, and limb breakage. During the day, south and southwest sides of trunks are warmed by winter sun. Cambium and phloem cells deacclimate and are then subject to injury by cold temperatures when the sun goes down resulting in a 'frost canker'. Leaf and stem tissues can be damaged when warm weather in early winter suddenly turns very cold. Extended mild winter temperatures followed by an extreme cold spell in the spring also can predispose normally hardy plants to cold injury.
Management Options

Non-Chemical Management
  • Do not fertilize, prune, or water heavily late in the season. This can encourage late-season growth that may not acclimate well in the fall.
  • Prune out only dead and severely damaged wood; prune back to live, green, healthy wood; prune to a bud, stem, or trunk.
  • Water properly throughout the spring, summer, and fall. Check soil moisture for evergreens and plants under eaves, and water when necessary.
  • Apply loose organic mulch over the root zone to maintain soil moisture and give protection from cold temperatures.
  • On damaged fruit trees, remove as much developing fruit as possible. This allows the tree to recuperate rather than produce fruit.
  • Select plants hardy for the local climate and soil conditions, especially native plants.
  • Place evergreens in areas that minimize their exposure to sun and wind. If this is not possible, provide shading or a windbreak during the winter months.
  • Wrap trunks of recently transplanted trees with a white or light-color bark-wrap in the fall, especially younger trees or ones with dark bark.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

Images
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Caption: Winter damage on apple
Photo by: R.S. Byther
Caption: Winter damage on apple
Photo by: R.S. Byther
Caption: Winter damage on apple
Photo by: R.S. Byther
Caption: Cold damage on camellia
Photo by: R.S. Byther
Caption: Flower bud damage on rhododendron
Photo by: R.S. Byther
Caption: Winter damage on rhododendron
Photo by: R.S. Byther
Caption: Winter injury on photinia
Photo by: R. Maleike
Caption: Winter injury on English/cherry laurel
Photo by: R. Maleike
Caption: Winter injury on Asian pear
Photo by: R.S. Byther
Caption: Winter injury on pine
Photo by: R.S. Byther