Say No to ‘Mulch Volcanoes’
Simple Fix Protects Tree Health
May 1, 2026
“Mulch volcanoes,” where mulch is piled high against tree trunks, are a common sight throughout Rockville and it’s not doing trees any favors.
Stacking mulch against the tree’s trunk creates moisture buildup that can lead to rot and disease. The barrier also creates hiding spots for pests and can cause roots to grow in unhealthy patterns, sometimes wrapping around the tree and cutting off nutrient flow. Additionally, thick mulch layers can limit oxygen from reaching roots.
Instead, spread mulch in a flat ring around the tree base, keeping a 2-3 inch space between the mulch and the trunk. Maintain a depth of about 2-3 inches, extending the mulch outward around the tree’s base, rather than building upward.
Pulling mulch back from tree trunks to expose the top of the root flare is simple and can make an immediate difference. Proper mulching supports healthier, longer-living trees that provide shade and character to neighborhoods.