Why Mulch Volcanoes are Bad

Why Mulch Volcanoes are Bad

Why You Shouldn’t Build Mulch Volcanoes Around Your Trees

You see it everywhere–mulch piled high around the trunk of a young tree. It looks nice. Lots of mulch was used, giving the impression that no expense was spared toward giving this tree a great head start in life.

Unfortunately, these “mulch volcanoes” are a clear example of “just because everyone else is doing it, doesn’t mean it’s a good idea.”

What is a Mulch Volcano?

Mulch volcanoes involve creating a mound of mulch around the base of a tree. The mulch is heaped tallest around the trunk, sometimes up to a foot in height. The volcano then slopes downward to establish a circle around the tree, which is around 3-10 feet in diameter. Here’s the key takeaway: mulch is good for trees, but too much mulch piled high around a tree trunk is harmful, and often a death sentence for a promising young tree. 

What Happens to a Tree When You Pile Mulch High Around Its Base

First of all, there are several benefits to landscaping with mulch around your young trees. Mulch helps in the following ways:

•   Creates a buffer to protect the tree during lawn mowing

•   Helps the soil retain moisture

•   Helps keep the soil cooler in the summer and warmer in the winter

•   Prevents soil erosion and runoff

What Problems Develop? Why are Mulch Volcanoes Tree Killers?

It’s a good idea to use mulch when planting or caring for a tree. However, volcano-style mulching does much more harm than good. Mulch volcanoes are problematic because they cover the bark.

The bark is a tree’s protective layer. This layer is meant to be exposed to air. Dig down below the surface around a tree, and you’ll find roots, not bark. Maintaining this distinction of exposed and unexposed tree material is important. 

When exposed to air, bark stays dry and hard. When surrounded by mulch, the bark becomes wet and soft. Then insects and diseases are able to penetrate into the tree, often initiating a slow process of decline and death. A mulch volcano essentially turns the base of your tree into a compost heap. 

A lower trunk surrounded by mulch might even start sprouting adventitious roots – roots that emerge from the trunk rather than from actual root tissue. This is a sort of desperation tactic by a tree in response to stress. These roots impair the normal movement of water through the organism and can eventually form spiraling roots that strangle the trunk.

The Best Way to Landscape the Area Around a Tree

Properly mulching a tree is not difficult. The best mulch varieties are wood chips or shredded bark. 

To apply mulch around a tree, first, remove any weeds growing in the area that you’ll be treating. Then layer mulch around the tree, extending 2-3 feet from the trunk. Use a maximum mulch depth of 2-3 inches. 

Mulch shouldn’t touch the bark at all. For the few inches of space immediately surrounding the trunk, don’t apply mulch. The resulting shape from proper mulching is more like a donut than a volcano. The center is a hole, rather than a peaking slope. 

If your tree’s diameter is 10 inches or larger, you really don’t need mulch at all. If you’re mulching for aesthetic purposes, do so conservatively. 

Sustainable Landscaping and Tree Care

Mulch volcanoes are an unfortunate example of copycat landscaping. It’s a trend that spread quickly and became the norm for suburban tree planting. However, if you want your trees to live long, healthy lives, pass on the volcano-style mulching. 

Hire a Professional Landscape Company Today

If you are looking for landscaping design and maintenance services, look no further than right here. Fernandez and Sons have built an excellent reputation providing years of high-quality landscaping services throughout northern New Jersey. Contact us to learn more and get a free estimate. We can assure you that your trees will be healthy and look great under our care.