Drive through almost any neighborhood and you’ll see it: trees surrounded by towering piles of mulch stacked into miniature volcanoes. It might look neat and intentional, but this landscaping shortcut is quietly killing trees. Known as “mulch volcanoes,” this practice is more harmful than helpful, and it has become so widespread that experts now call it a ‘landscaping epidemic.’
At Horstmann Brothers Landscaping Services, we’re here to explain why mulch volcanoes are choking trees, and what you can do instead to keep your landscape healthy and thriving.
Why Mulch Volcanoes are Deadly for Trees
Mulching has many benefits when done correctly. A proper 2 to 3-inch layer of mulch helps retain soil moisture, regulate soil temperature, and reduce weed competition. But piling mulch high against a tree’s trunk turns this helpful practice into a silent killer.
- Trapped Moisture Leads to Rot and Disease
When mulch is stacked like a volcano, it traps moisture directly against the bark. That damp environment becomes the perfect breeding ground for fungi, bacteria, and insects. Over time, the tree’s protective bark begins to soften and rot, leaving it vulnerable to decay and pest infestations. What looks like “extra care” can shorten the lifespan of your tree.
- Oxygen Deprivation in the Root Zone
Healthy roots need oxygen. A thick mound of mulch smothers the soil beneath, creating oxygen-poor conditions. Without proper airflow, roots struggle to function, weakening the tree from the inside out. A suffocated root system means your tree cannot absorb the water and nutrients it needs.
- Shallow, Weak Root Systems
Perhaps the most dangerous consequence of mulch volcanoes is how they change root growth. Instead of spreading outward into the soil, roots begin to grow upward into the mulch itself. These shallow, circling roots, called adventitious roots, wrap around the trunk and create girdling, effectively choking the tree. Even worse, these weak root systems fail to anchor the tree, making it far more vulnerable to wind damage and storm blow overs.
What Proper Mulching Should Look Like
The good news is that mulch itself isn’t the problem. It’s how it’s applied. The goal is to mimic nature. In forests, organic matter like leaves falls to the ground in thin, even layers, never stacked against trunks.
Here’s how to do it correctly:
- Keep mulch 2-3 inches deep (never more).
- Always pull mulch back from the trunk, leaving a few inches of bare space around the base of the tree.
- Extend the mulch ring outward to cover the root zone rather than upward around the trunk.
- Refresh mulch lightly once or twice a year instead of piling new layers on top of old ones.
By following these steps, you protect your tree’s bark, encourage strong outward root growth, and maintain a healthy soil environment.
Why Professional Care Matters
DIY mulching often leads to volcanoes because it seems like the easiest, fastest option. But what looks tidy can be deadly to your trees. Professional landscaping teams, like Horstmann Brothers, understand tree biology and apply mulch in a way that supports long-term growth and stability.
Our trained experts not only mulch correctly but also spot early signs of stress, disease, or improper planting. By investing in professional garden care, you ensure your trees don’t just survive but that they thrive for decades.
Protect Your Trees Today
Mulch volcanoes may look harmless, but they slowly choke the life out of trees. The best way to protect your landscape investment is to mulch properly and trust the experts.
At Horstmann Brothers Landscape Services, we take pride in keeping trees strong, stable, and healthy. If you suspect your trees have been buried in mulch volcanoes or want to make sure your new plantings are mulched the right way, we’re here to help.
Contact us today to schedule a consultation and give your trees the care they deserve.