Are You or Your Landscaper Killing Your Trees with Volcano Mulching?

It is very common to see “volcano mulching” around the base of trees in a residential and commercial landscape. But is this what is best for your tree? Short answer: No! Volcano Mulching is easy to spot because the mulch is piled high around the base of the tree, creating a mountain of mulch that somewhat represents a volcano.


Often home-owners and landscapers think that merely adding mulch around the base of the tree is adding a benefit to the tree but that cannot be further from the truth. Although the intention is typically useful when adding mulch around the base of a tree, a lack of understanding of tree biology is at the root of this standard and often fatal mistake.

So why is volcano mulching so bad? At the base of a native tree or a tree that was planted at the proper depth, is what is called the root flare. The root flare is the transition from the trunk and bark of the tree – to the root system. Before we dive into tree biology lets discuss a fun way to think about the root flare. When you look at the base of your tree, you want it to look like the bottom of a wine glass where you see the trunk “flare” out before entering the ground. All too often we see trees that look like “telephone poles” at the base which is an indication of serious problems that we’ll discuss below.

Just like humans have different cells – hair, skin, nails, etc.– all that have different functions and purposes, trees are similar in this regard. When a tree is either planted too deep or too much mulch is added around the trunk (telephone pole), the root flare is often covered. Because the cells of the trunk and root flare are not the same as those of the roots, when exposed to the moisture, organic matter, insects and fungus that inhabit both the soil and mulch volcanoes, they have a much higher chance of premature decay compared to the roots that are meant to live within these conditions. Once the base of your tree has decay, it often creates a mortal wound that is an easy entry point for insects and infestations or will prevent the tree from ever reaching its fullest potential.

You may be asking, then why do landscapers mulch at all then? Although the practices used by many landscapers are wrong because of lack of arborilogical education, properly mulching your tree does have several benefits. When mulching is appropriately done, it helps retain moisture and regulates temperature for the root system and adds organic matter to the ground (although it takes time for it to break down and be useful for the tree). Mulching also creates a definitive barrier around the base of the tree to help protect the trunk from lawn crews that often weed whack around the base of a tree damaging both the bark and the cambium, the layer of a tree that transfers both water and nutrients.

So, how can you ensure your trees are planted at the proper level, have their root flare exposed and are not mulched improperly? Certified Arborists are trained in tree biology and have a great understanding of the conditions that will help your tree thrive and be as sustainable as possible.

Give us a call at (817) 329-2450 to set up a consultation to check the health and condition of your trees today!