Winter burn is a common occurrence to boxwood, holly, rhododendron, and most conifers. Winter burn symptoms often develop when temperatures warm up in late winter and early spring. This type of winter damage is often misdiagnosed as an infectious disease or damage from excessively cold temperatures.
To understand winter injury, it is important to understand that while a plant is creating its food by photosynthesis, it is releasing large amounts of water through the process of transpiration (the evaporation of water from the plant). Over the course of a day, a large tree can lose hundreds of gallons of water. When plants are unable to obtain the water they need (due to drought or frozen soil), the water lost through transpiration cannot be replenished, resulting in dehydration, foliar damage, and even death.
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Michael Mickelbart, Clinical Engagement Assistant Professor
Horticulture and Landscape Architecture
Janna Beckerman, Associate Professor
Botany and Plant Pathology