Stop the Mulch Volcanoes!

Glen Ellyn, it's time to start a movement against "mulch volcanoes." This movement won’t require you to march in the streets, but you will need to march to your parkways and yards to participate.

Mulch is an important additive to trees but a common practice in this area is damaging our foliage. Mulch is important when used properly; it holds in moisture and discourages weeds and grass from growing that can rob tree roots of water and nutrients. It also creates a barrier from lawnmowers and weedwackers that can cut into bark. And, it introduces a colorful texture to the landscape that contrasts well with grass and plantings.

“Mulch volcanoes”, are mounds of mulch that are too tall, applied around the base of trees--in the shape of a volcano. Although they may be aesthetically pleasing, they are bad practice because they hurt the tree, which is not good. They encourage fungal rot, which once it has attacked a tree, it is almost irreversible and leads to teh death of a tree. Excessive mulch piled against tree trunks also invites wood borers to nest and provides a habitat where many insect pests can live and reproduce. And soggy, thick mulch layers drain too slowly, causing a loss of oxygen in the soil. I have seen mulch volcanoes rising 15” above ground line in my neighborhood. Many of them are created by the lawn crews hired to make our landscaping “look nice”.

The Morton Arboretum provides great information on the care of Midwest trees, and the correct application of mulch. The best method is to lay a 3- to 4-inch layer of mulch in a very wide ring around the trunk, not letting the mulch directly contact the trunk and basal root flare. Create what is called a “berm” or “well” around the tree. The well should begin at least 4-6″ away from the trunk of the tree, then build the berm in a circular fashion around the tree. This will allow water to collect at the base, rather than having it roll away from the tree where it is less beneficial. The berm should only be a few inches tall, certainly not 15” tall.

Linda Gilbert, President of Citizens for Glen Ellyn Preservation states that “our whole CGEP board is strongly behind tree protection and preserving our village tree canopy. Over-mulching is much more common than I had realized. A number of our members have been helping with a volunteer program started by our forester in tagging some 1600 ash trees on public parkways.

Members of our community have seen so many of these trees “eaten alive” from Emerald Ash Borer that are also being rotted from the outside at the base, due to mulch placed against the bark.