Pruning

• Pruning a damaged plum tree soon after the damage occurs is important. Whether the damage is due to weather, a falling tree or mechanical injury, removing the dead branches from the plum tree helps prevent harmful insects and pathogens from making a home in them and attacking the plum tree. Examine the plum tree and look for branches that have broken completely off and that do not show signs of recovering. Prune dead branches from the tree.
  
  

Fertilizer

• An immediate application of fertilizer after a plum tree has sustained damage is one way to help jump-start the tree's natural healing process. An infusion of crucial nutrients like nitrogen, potassium, phosphorus and magnesium helps the plum start to rebuild damaged areas and produce new, healthy growth. Avoid placing fertilizer directly on the roots of the plum tree, as fertilizer burn will only do more damage to the plum. Spread fertilizer evenly over the soil.
  
  

Pest and Disease Control

• Begin or continue a regimen of pesticide and fungicide sprays on the plum tree. Plums with damaged branches are at a much higher risk of infection and infestation from harmful insects and pathogens, and may hasten the death of trees. Avoiding damage from pests and diseases helps keep plum trees alive after they are injured. Spray pesticides and fungicides according to the directions on the package for the best results, and wear proper skin and eye protection when working with chemicals.
  
  

Assess the Plum Tree

• Keep a watchful eye on the plum tree during the months that follow damage. Continue watering and fertilizing the tree as normal. If the tree shows signs of recovery, such as the production of new branches, it is likely that it will survive. If the plum does not start producing new leaves or branches in the spring, however, remove it from the garden before it becomes a falling danger or hosts pathogens that harm the rest of the plants.