If girdling roots are the cause, it may be possible to cut them out. Dieback Rapid dieback may be due to damage from rabbits, mice or moles feeding on the lower stems or trunks. Leaves turn yellow, wilt, and droop. Leaf petioles and the base of the leaf blade may turn brown or black. Later, brown, rotted tissue may be evident at the base of the plant.
Plants become loose and wobbly, pulling easily from the soil.
These diseases are most severe during high soil moisture and high temperature periods. Once plants become infected, they rarely recover. Remove diseased plants. Improve drainage of the planting site. Do not plant sensitive plants in wet areas or cover roots with heavy mulches.