What is a Mulch Volcano?
A “mulch volcano” is a large pile of mulch heaped up against the trunk of a tree. These piles, while often the work of landscaping companies, are very harmful to trees. They place stress on root flares, bark and deep roots, which can lead to decay and disease.
Mulch Volcanoes Cover Root Flares
Mulch volcanoes cover a tree’s root flare. This encourages the growth of moisture-related pathogens. Rotting bark exposes underlying conductive tissue to insects and disease. This leads to weakening of the tree trunk and roots.
For more on the importance of keeping root flares exposed, please read our article: Exposing Root Flares and Tree Health.
What Can You Do to Correct this?
First, remove the mulch away from the trunk and root flares of the tree. Mulch should be applied at least 3 inches from the tree trunk and root flares.
Second, spread the mulch evenly, no more than two to three inches thick, over the tree’s critical root zone. Absolutely no landscaping fabric should be used, which will impede the essential exchange of oxygen and carbon dioxide in the soil and roots.
Benefits of Proper Mulch Application
- Suppresses weed growth
- Protects soils in the winter and the summer from extreme temperatures and drought
- Protects from mechanical damages caused by string trimmers and mowers
- Encourages the healthy microbial activity in the soil as the mulch decays
