This is especially important in upstate areas where the soil can freeze and remain frozen on sunny days. When this happens, the foliage continues to transpire but the roots cannot replace the lost moisture from the frozen soil. If boxwoods have died and boxwood decline disease is confirmed, do not plant English boxwood in the same site. American boxwood can be used as a replacement as it is resistant to decline. But if Phytophthora root rot is confirmed, the site should be avoided for future boxwood plantings.
Leaves turn from normal dark green to light green as the plant declines.
Roots are dark and rotted. The bark rots and peels at the crown. Death of the entire plant is characteristic of this disease. Root rot is favored by high soil moisture and warm soil temperatures. The disease is more severe in heavy clays or poorly drained soils.