Gary Haygood > Blog > Don’t Make Volcanoes When Applying Landscape Mulch

Don’t Make Volcanoes When Applying Landscape Mulch

Oct 6, 2017 0 Blog, Garden, Green, Landscape Architecture, Lawn Maintenance, Lawns

According to Gary R. Bachman with the Mississippi State University Extension Service, people aren’t using mulch properly, and this can cause damage to your trees. Adding a layer of mulch around the base of your trees can reduce weeds, cools the soil and most importantly, conserves precious water in the tree’s root zone when done correctly.

Bachman suggests the following for proper mulching:

  • The ideal mulch thickness is 2 to 3 inches, but some gardeners think 6 to 10 inches has to be better, and so mulch volcanoes are born.
  • When a thick layer of mulch is spread around the trunk of a tree, many things can happen, and they’re all bad. The mulch will indeed hold moisture, but it will be up against the tree trunk, creating a condition where the bark starts to decay. This problem allows fungi, bacteria and insects to get under the bark and cause problems internally for the tree.
  • Circling roots are another problem commonly found in mulch volcanoes. In this moist environment, a tree will begin to grow roots into the mulch instead of outward into the surrounding soil. Most mulch volcanoes are circular because that’s the way most homeowners place mulch around trees. Roots will start to circle the tree, staying in the mulch.
  • An example of root circling can be seen with bedding plants or any plant grown in a container. Many consumers will look at the roots of a container-grown plant before purchasing it. They are looking for roots that circle the inside the container. These roots never grow out into the soil, and the plant will not perform well in the landscape.
  • As the tree grows, the circumference of the trunk grows larger, and the circling roots eventually strangle the tree. However, the tree does not die immediately. It goes through a prolonged period of decline.
  • The proper way to mulch a tree is to first spread an even 2- to 3-inch layer around the base of the tree. The diameter of this mulch is up to the home owner. I personally like big mulch beds around trees to ease lawn mowing and reduce edging, but that is a topic for another column.
  • After the mulch is applied, use a rake or your hands to pull the mulch back away from the tree trunk. It is OK to leave a thin layer to avoid exposing bare soil, as long as the mulch does not touch the tree trunk. As you pull the mulch back, contour it to resemble a bowl. This shape helps to collect water and direct it towards the root system of the tree during rain or irrigation.
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