Somewhere, right this moment, someone is “volcano mulching” a tree. You’ve no doubt seen this practice but maybe didn’t realize that’s what it was called, or that it was harming the tree. Like the name suggests, volcano mulching is when you build up a mountain of mulch around the tree with the trunk erupting from the center. To understand what is wrong with this, let’s first learn why we put mulch around a tree in the first place.

The purpose of mulching a tree

Mulch looks great around trees, giving it a clean, tidy look. But that’s not really the main reason we use it. Trees in the wild get the benefit of “litter,” all that decomposing matter like leaves, branches and other biological material. Unlike trash, this litter is good, giving the trees moisture and nutrients as well as protecting it from extreme heat and cold. 

But in a landscaped lawn, people don’t generally leave decomposing forest litter around, so we instead mimic it with mulch. Good mulching will spread a thin layer of mulch to the full circumference of the root area. If you need a guide, the roots spread about as far as the branches, so you can look up to get an idea. 

When you get close to the tree though, leave a little hole to allow the tree to breathe. The mulch should not come in direct contact with the trunk — for reasons we will discuss in a moment. This wider circle with a hole in the middle is called “donut mulching.” Remember: donuts are good, and volcanoes are bad. 

Why volcano mulching harms a tree

Without this donut hole, mulch comes in contact with the trunk. Because mulch is meant to hold onto moisture, the tree trunk is being smothered with a moist blanket. This brings mold, mildew, and bugs and also will rot the trunk alive.

The higher this mulch volcano goes, the higher the area that is being exposed to moisture and left to rot. There are many pictures online of people flattening their mulch volcanoes only to discover the first three feet of their trunks are now rotten. 

In addition to the moisture problems, it also confuses the root system. Feeder roots usually have to plow through harder soil to get moisture and nutrients. But if they can grow upwards into soft mulch, they will. These upward roots may begin to grow back downward if the volcano is flattened, but regardless, you will have large above ground roots for the remainder of the life of the tree. 

Anthony’s trained staff knows how to properly mulch trees

If you live in the Bloomington, Indiana, area, and want to have your property mulched the right way, contact Anthony’s Lawn Care and Landscaping. We take great care with our customers’ trees and always avoid mistakes like volcano mulching. Call us today at (812) 929-9463 for more information.