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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Winter Desiccation Injury to Conifers

This article was published originally on 4/12/2013

The first samples to come in through the clinic at the beginning of the season are generally conifers and evergreens. We sometimes diagnose disease or insect-related problems on these samples, but for the most part, we diagnose problems due to environmental conditions.
 
Lately, we have been noticing some needle browning on all sorts of conifers, especially white pine and Concolor fir. Many of these browning trees are suffering from winter desiccation. This is usually associated with lack of moisture in the soil, especially when trees are subjected to sun and winter winds. Needles appear yellow or brown because they continue to transpire during winter. However, since the ground frozen, needles are unable to replace all the moisture that is lost during the process.
 
Winter desiccation injury is often most severe on trees in exposed site or on the south and west sides of trees. The extent of damage may vary depending on the tree species, location, and weather conditions. However, if the damage is not too severe, the tree should resume normal growth in spring. To avoid winter desiccation in the future, make sure to choose tree species appropriate for your region. In addition, planting trees in protected or sheltered can help prevent unsightly needle browning.
 
 
Thinning pine and needle drop from winter desiccation injury.
Thinning pine and needle drop from winter desiccation injury.
Needle browing from winter dessication injury.
Needle browning from winter desiccation injury.