Volcano Mulching

Volcano Mulching

“Volcano mulching” is a term used to describe a detrimental mulching practice where a large mound of mulch is piled up around the base of a tree or plant, resembling a volcano. This mound can sometimes reach a foot or more in height.

This practice is not recommended and can have negative effects on the health of plants and trees. It can cause excess moisture to build up at the base of the trunk, which can lead to rot or infestation. It can also encourage roots to grow into the mulch, instead of spreading outwards which gives the tree its ability to keep itself stablized during storms. 

Once you start to notice volcano mulching you’ll see it everywhere in commercial landscaping and the yards of well-meaning homeowners. Below is more information to help you keep your trees healhty. 

How to Avoid Volcano Mulching

  1. Create a Mulch Donut: Spread a layer of mulch in a donut shape around the base of the plant, leaving a gap of a few inches between the mulch and the trunk or stem.
  2. Apply the Right Amount: Apply a layer of mulch that is 2-4 inches deep. Avoid excessive mulch that can suffocate the plant.
  3. Keep Mulch Away from Trunk: Maintain a clear area around the base of the plant to prevent moisture buildup and discourage pests.
  4. Choose the Right Mulch: Use organic mulch materials like wood chips, straw, or compost. Avoid using plastic or synthetic mulches that don’t break down and can trap moisture.
  5. Monitor Plant Health: Regularly inspect your plants for signs of stress, disease, or pests, and adjust your mulching practices accordingly.


Notice the donut shape of the mulch in this photo. The base of the trunk is visible and you can see where the trunk enters the ground. The root collar is where the first root shoots out from the trunk. Remember this flare should sit above ground- prefereable 1 -3 inches above the level of the dirt. Creating a mulch donut with room around the base of the tree should reveal the flare of the root collar.

Get a refresher on planting trees here.