University of Maryland Extension

Broken Branches and Lower Trunk Damage

broken stems on azalea
Broken stems on an azalea shrub

Key Points

  • The death of one branch or scattered dieback throughout a tree or shrub may be the result of mechanical damage (damage caused by equipment or a weather event) to branches or damage to the lower part of the trunk. 
  • Branch or lower trunk damage opens the tree or shrub to disease and insect organisms, which may further damage the plant.
  • Severe bark or trunk damage restricts a plant’s ability to transport water, nutrients and food.
  • Small amounts of damage can be tolerated but repeated damage that results in large masses of scar tissue is a serious problem.

Causes of Damage

  • Lawn mowers, tractors, and string trimmers are the primary cause of mechanical and lower trunk damage to plants. Trees and shrubs planted near parking lots, sidewalks, driveways or roads are also vulnerable to damage from cars or foot traffic bumping into them.

  • Excess mulch, planting too deeply, and animals such as rabbits and voles can also damage the lower bark on trunks of trees and shrubs.

  • Storm damage.


  • Prevention is important because damaged bark or branches cannot be reattached or repaired. 

  • Trunk damage and mechanical injury can be avoided by maintaining mulch rings around ornamentals and keeping weeds down to a minimum. 

  • Prune out broken branches as soon as possible. 

 mechanical damage
Broken branches on juniper


Rev. 2019

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