Mulch Volcanoes: Too Much Of A Good Thing

Mulch VolcanoesRecently we came across a Facebook photo about mulching. It says what we have tried to inform people for years. Properly applied mulch provides a lot of benefits to your tree; however, if you use too much mulch you are doing damage to your tree. In this video and article, you’ll learn why over mulching is detrimental, how to properly mulch, and get to see how our Arborists fix these issues using Root Collar Excavations.

Properly applied mulch should be 2-4 inches deep and extend out to the edge of the tree’s crown or beyond.

proper mulching

Benefits Of Properly Applied Mulch:

  • Insulates the soil helping to provide a buffer from heat and cold temperatures.
  • Retains water helping to keep the roots moist
  • Keeps out weeds to help prevent root competition
  • Prevents soil compaction
  • Reduces lawn mower damage.

When too much mulch is built up around the trunk of the tree you get what Arborists call a mulch volcano.

Effects Of Mulch Volcanoes:

  • An increased susceptibility to insects & diseases caused by mulch irritation on the trunk of the tree.
  • Girdling Root Systems – a condition where smaller roots wrap around a dominate root choking it and not allowing the tree to absorb nutrients.
  • Rodent issues – mulch piled high against the trunks of trees create habitats for rodents that chew the tree’s bark.
  • And Root Rot from excess moisture

Recently we performed work on a client’s trees that were suffering from mulch volcanoes and improper mulching (See Photo Below).

1) First, we performed a Root Collar Excavation using pressurized air to expose the roots for inspection without hurting the tree.

2) Once the root system was visible it was obvious that the excess mulch had caused roots to grow from the main trunk and around dominate roots. This is problematic and could lead to numerous health problems and even the death of the tree in the future. We also noticed discoloration on the trunk from mulch irritation and excess moisture.

3) To fix the problem and keep health issues from occurring we hand pruned the roots. By removing the problematic roots we returned the root structure to a healthy state which will allow the root system to grow properly and thrive in the future.

4) Lastly, we properly re-mulched the tree.  You can see by the dirt lines on the trunk how high the mulch used to be. Notice that our proper mulching is much lower and does not pile up against the trunk of the tree.

If your trees have mulch volcanoes they most likely are starting to develop root issues, like the ones in this article & video. We suggest haveing a root collar excavation and root pruning performed on your tree to identify and fix your trees’ root issues before the effects become irreversible.BEFORE (2)

Learn more about mulching around trees

One thought on “Mulch Volcanoes: Too Much Of A Good Thing”

  1. Anna says:

    Yes Samantha, those mulch volcanoes are definitely a big no-no. Yet, I see it all too often around my neighbourhood. You need to keep it shallow around the base – I am doing this with my trees. I was looking at other articles for inspiration on how to landscape around trees, and this is a good supplement to that. I suppose the approach for mulching will differ slightly depending on the type of tree, no? Anyway, you can expect a call from me shortly. Thanks for the helpful post.

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