Curse of the Mulch Volcano

We hear a lot about applying mulch around plants, shrubs, and trees to aid in moisture retention and deter weed growth. We have all driven past beautiful landscapes that are manicured to perfection. But there is a trend in landscaping that home owners and gardeners need to be aware of. It is called a “mulch volcano.” Simply put, it is mulch piled too high around the base of a tree. Did you ever have one of your children make the comment, “Everyone is doing it. Why can’t I?” This is the very misconception of mulch volcanoes. The fact is that too much mulch will limit a tree’s life span to approximately seven years.
Here’s why:

The warm, moist conditions provide the perfect environment for fungi to grow and spread. The bark then begins to decay, allowing fungus and disease to penetrate the tree.
Piling mulch high onto a tree encourages rodents to make their homes there. They will then begin to chew on the bark, causing girdling of the tree. In severe cases of chewing, the tree is killed.

Tree roots need to breathe. Mulch piled too high causes root suffocation.

Decomposing organic mulch can create a barrier that prevents water to penetrate in dry areas or evaporate when excessive rain has fallen.

Insects have ability to sense when a plant is weak and will be drawn to infest it.

The National Arbor Day foundation and the International Society of Arboriculture recommend mulching trees this way:

Add mulch to the base of your tree by removing any grass within a 3 to 10 foot area depending on the size of your tree. Pour natural mulch such as wood chips or bark pieces 2 to 4 inches deep within the circle. Keep the mulch from touching the trunk of the tree.