Can Too Much Mulch Kill a Tree in Lakewood, OH?

Petrarca Landcare, your expert tree service in Lakewood, Ohio, offers useful advice about growing healthy trees. 

In this post, we’ll answer another commonly asked question—can too much mulch kill a tree? The short answer is “Yes.” However, let’s look at how too much mulch affects soil health and how it kills the tree.

Why are Mulch Volcanoes Bad? 

Over-mulching causes several issues, namely:

  • Root suffocation: The layers cut off the oxygen supply to the roots. This causes them to suffocate and die. 
  • Soil waterlogging: Mulch is an effective way to retain soil moisture. However, if it’s too thick, the roots never get a chance to dry out and become susceptible to rot and fungi. 
  • Trunk rot: If there’s excess organic matter, it’s bound to pile up against the tree. Where it touches, it may rot the bark.
  • Fungal and bacterial diseases: If the mulch layer is too thick, it becomes a breeding ground for fungi and bacteria. The process of decomposing increases this risk.
  • Heat damage: Decomposing plant matter releases heat. When that layer’s too big and too near the trunk, this warmth damages the bark. 
  • Changes in soil pH: The type of mulch you use can also create an issue when it decays. If you use wood chips, for example, they might make the soil too acidic. 
  • Pest infestations: Bugs and rodents might make their homes in the organic matter and start to breed. 

Signs of Over-Mulching

Can too much mulch kill a tree? The problem here is that you won’t realize that there are any issues straight away. It may take as long as five years for the following signs to start showing: 

  • Discolored leaves
  • Stunted branch growth
  • Smaller leaves than normal
  • Branch dieback

You should also look for signs of root rot and other signs of fungal infections. 

How to Deal With Volcano Mulching

The solution depends on how long the situation’s been building for your tree. If it’s only a small tree, you can try to excavate the area (carefully). 

  • Gently straighten any roots that are circling around and leave the rest as undisturbed as possible.
  • Fill in the gap with loamy topsoil.
  • Add a reasonable layer of mulch. 

If the problem’s more advanced, or you run into too many surface roots, call in the experts. 

Proper Mulching

Your mulch layer shouldn’t be higher than three or four inches at the most. You want to avoid the “volcano” look that peaks at the trunk and opt for a “donut” look instead. Leave 12 to 18 inches from the trunk before laying the organic matter. 

If you’ve the space to do so, extend the mulch layer to just beyond the tree’s drip line (where the outer edges of the canopy end). Rake up the matter once a year to loosen it, but don’t remove it. 

Contact Our Team for Expert Tree-Related Advice

Now you know the answer to “Can too much mulch kill a tree?” Are you concerned about your yard? 

Call Petrarca Landcare at 330-933-0562 to evaluate the situation. Our experience could save a stressed tree.

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