When there is snow cover, deer thrive on white cedar, Norway pines, and other evergreens. Deer Guard must be applied at above freezing temps, recommended after the first frost and when leaves are down. Then they are protected from rain, snow, sleet, etc. through the winter.

Deer Guard was tested by the University of Minnesota in St Croix and northern Minnesota counties and is the proven deer repellent for sub-freezing winter protection of trees, evergreens, and shrubs. Odor based repellents do not work in freezing temperatures. Deer Guard uses the bitterest substance known to man and a detection agent so deer learn to avoid Deer Guard treated trees, evergreens, and shrubs. Applied in above freezing temperatures, Deer Guard literally bonds to the plant's surface using a latex formulation.