Snow & Ice

Pathogen Type

Frequency

Severity

Hosts

Almost any plant is susceptible to this injury, but multiple leader evergreens and narrow vase shaped deciduous trees are more susceptible.

Symptoms

Snow and ice can cause severe damage to not only junipers but also to arborvitaes and many other trees and shrubs. The sheer weight of the snow or ice may exceed the breaking point of the limbs. The breakage can cause large gaps in the plant,often ruining the appearance of the plant. If the snow or ice is followed by a severe temperature drop and gusty winds, the damage is often more severe because the wood is more brittle and the wind causes additional breakage. Sometimes the snow or ice does not cause any breakage. Instead the weight bends the stems over. Multi-stem plants seem to be more prone to this damage than single stem plants. If the bending over occurs at the wrong time or lasts too long, permanent internal structural damage is done to the trees wood. When this happens the tree does not return to an upright position by itself.

Management

Carefully remove the snow while it is snowing and before branches begin to break. Keep in mind that "wet" snow is heavier than "dry" snow and thus, is more likely to damage trees. Remove the snow carefully during cold temperatures to avoid breaking limbs with the broom or what ever is being used to remove the snow. As for the ice, it is very difficult to remove with out damaging the plant so it is probably best to let nature take its course. In addition, the multiple stems may need tying. Use something that will not cut into the bark or cause girdling. Instead of tying individual branches, encircle all the stems in one loop. Old pantyhose make very good tying material since they are made of nylon and take forever to decay. The pantyhose does not cut into the bark easily and if used in one large loop it does not usually cause girdling.

Credit

James E. Schuster, retired Extension Specialist, Horticulture & Plant Pathology, University of Illinois

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