Is Winter Damaging Your Landscape?
Posted: February 17, 2015
- If the plants in your landscape are native to Northeastern Pennsylvania, or they are hardy to zone 6b (which typically experience an average annual minimum temperature of -5 to 0 degrees F), they will be able to tolerate the cold, but plants like Crape Myrtle, Blue Atlas Cedar, or Sweetgum might see some damage to twigs and buds.
- Some multi-stemmed shrubs and trees like birches, arborvitae and yews can sustain some branch damage when snow loads bend them down towards the ground. It is best to try to knock heavy snow loads off of branches before they bend or break, or cable multiple stems together to add strength, or use rope and tie up arborvitaes or yews prior to winter snows. Ice on branches can increase the weight loads for trees by 10-30 fold, depending on how thick the ice forms. If trees are damaged by ice, it is best to have an ISA Certified Arborist evaluate the tree to see if the damage can be repaired or if the tree should be removed.
- One of the real silent winter killers of plants is the use of deicing salts. Trees and shrubs are affected by salt in many ways. Salt in the soil is highly absorbent, depriving roots of water. When sodium chloride dissolves, free chloride ions are absorbed by roots and carried to the leaves and needles where they accumulate to toxic levels, drying or burning leafy tissue. The sodium ions damage soil causing it to loose pore space and become more compacted. Sodium also restricts the plants uptake of magnesium and potassium that are needed for photosynthesis. When salt sprays from roads splash on twigs and buds, the salt enter the cells and causes damage (twig dieback).
- Salt injury may be seen in the spring as brown needles; tip/branch dieback; stunted, yellow leafs; browning scorch to the leaf margin; or early leaf color and drop in late summer.
- The best way to reduce or minimize salt injury to plants is to avoid using de-icing salts around landscapes or pilling salt laden snow into planting beds. Using other chemicals such as CMA (calcium magnesium acetate), or course sand, or other products that do not contain sodium or chloride will prevent injury to plants. When spring arrives, it is best to thoroughly water your planting areas to flush the sodium and chloride through the soils.
For more information about maintaining a healthy landscape visit the Penn State Extension Home Lawn and Garden website or contact your local Penn State Extension Office.