Why Homeowners and Landscapers Should Avoid Volcano Mulch

Volcano mulching—piling mulch high against the base of a tree trunk—might look neat, but it causes serious long-term damage.

When mulch is stacked against the trunk, it traps moisture where the bark should stay dry. This leads to rot, fungal growth, and insect infestation, weakening the tree from the base up. Over time, roots may begin growing upward into the mulch instead of outward into the soil, creating girdling roots that slowly choke the tree.

Volcano mulch also hides structural problems at the trunk flare, making it harder to spot decay until the tree is already failing. For homeowners, this can mean unexpected tree loss or costly removals. For landscapers, it can mean unintentionally shortening the life of otherwise healthy trees.

The Correct Way to Mulch

The correct method is simple:

• Keep mulch 2–4 inches deep
• Spread mulch in a wide ring around the tree
• Pull mulch back several inches from the trunk so the root flare remains visible

A tree planted and mulched correctly is stronger, healthier, and far less likely to become a future hazard.