Prevent ‘Moweritis’ from Killing Your Young Trees and Shrubs

Young healthy trees in our landscapes and along our streets are dying overnight from an unusual cause.
Prevent ‘Moweritis’ from Killing Your Young Trees and Shrubs - Articles

Updated: August 8, 2017

Prevent ‘Moweritis’ from Killing Your Young Trees and Shrubs

Some might think it is being caused by a new disease infecting the root systems. Others think it could be another invasive insect boring into the wood or chewing the leaves that make food for the plant. The real culprit is us and our wonderful power tools that are used to cut grass.

If there is grass growing close to your young tree, then there is the potential for your tree to become inflicted with "moweritis". Whenever we use string trimmers or weed whackers to cut grass around trees, those flailing blades or plastic strings repeatedly wound the trunk of a young tree, tearing bark away that protects the important vascular, or water and food conducting tissues found just under the bark. I know we all think of tree trunks as wood, a very tough material, but trees are very vulnerable to wounds because their most important growth tissue, called cambium is just under the young thin bark. As the string trimmer nicks and beats off the bark in a circle around the circumference of the trunk, the tree will become girdled and the vascular tissue in the stem will die. Once the vascular tissue and the cambium (the thin layer of growth cells that creates new wood) is dead, the tree can no longer get water up to the leaves there it is needed to make food, or transport food down to the roots where it is needed to grow new roots. In essence, the tree dies because we wounded its trunk while cutting grass.

Now don't think this only happens when homeowners forget their fourth-grade science class, where they learned how plants grow. Much of damage being inflicted to young trees in the landscape is coming from lawn care professionals and landscapers that have not trained their workers and who are often in a hurry to mow the grass and move on.

If you have a young tree in your landscape that you want to grow into maturity and provide shade and beauty to your home, then you should,

Take the following steps to protect the trunk from mowers and string trimmers:

  • Apply a thin layer (2-4 inches deep) of mulch (wood chips) around your trees. Don't pile it up on the trunk - that can hurt the tree causing decay and rot to enter the trunk.
  • Place a thick plastic protective sleeve or tube around the base of your tree to a height of 12-18 inches. Flexible corrugated drainage pipe that is split open on one side works very well as a protective device that string trimmers can now hit as the grass is mowed.
  • Talk with your landscapers about this issue and check the base of your trees for damage.

Instructors

Urban Forestry Arboriculture Green Infrastructure Urban Stormwater Management

More by Vincent Cotrone