Desiccation During the winter evergreen plants continue to lose water by transpiration.
Water loss is greatest during periods of strong winds and on bright, sunny days.
Even though the air temperature is cold the temperature inside the leaf can be warm. The brighter the sun the higher the rate of transpiration. Desiccation occurs when water is leaving the plant foliage faster than the roots can replenish lost moisture. Root absorption is reduced or prevented when the soil is cold or frozen. The foliage of plants, such as camellia and boxwood, may turn yellow or orange due to mild desiccation or excessive sunlight.