Have you ever noticed that in some new landscapes the base of the tree is buried? Into this weird-looking cone shape? Well, if you’ve seen it, erase it from your mind! We’re going to tell you just why you shouldn’t bury a tree base.
Burying the base of a tree stops the vascular flow of water, oxygen and nutrients from getting to the rest of the tree. This makes the more susceptible to ailments, fungus, and pests over time. To properly mulch your tree, evenly spread mulch around the tree’s base up to 4in deep.
In this article, we’ll explain why you shouldn’t bury a tree base and what to do instead. Keep reading to find out more!
So, Is It Okay To Bury The Base Of My Tree?
No! You never want to pile any soil against the base of the tree!
What do we mean and what does this look like?
Burying the base of the tree isn’t the same as when you plant a new tree. It looks like a pile of mulch stacked around a tree trunk. This can look similar to a cone or a volcano and is often called a mulch volcano. This creates a multitude of problems for your tree and will eventually destroy it.
This can also look like mounds of mulch, or a cone shape stacked against the trunk of the tree. It’s not always done to all age trees, but if you’ve seen it, you’ve probably seen it around fairly young, and newer planted trees.
The weirdest part is that you’ll even see some landscapers doing this, which might make you think it’s okay and the thing to do, but we promise it is never okay!
Now, we aren’t saying to NOT mulch your tree but rather, we’re saying not to bury the base of the stump. Mulch is super great to have around your tree but is primarily beneficial for the roots.
Why Are Mulch Volcanoes Around Trees Bad?
This is a weird, yet popular phenomenon commonly referred to as volcano mulching. Volcano mulching is not good for your tree as it will create a number of issues down the road.
Mulching is great for your tree, but piling it up into a massive mulch pile or volcano is not the way to go. If you create a “mulch volcano”, you are limiting the amount of oxygen that can happen between the roots and the soil.
Lack Of Nutrients Reach The Roots
Additionally, this mulch pile tells the roots to grow into the mulch volcano rather than into the soil creating a girdling effect. Roots begin to grow in a circle around the tree trunk eventually restricting the vascular flow of water and nutrients.
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Causes Root Dehydration
Piling mulch against the tree trunk also causes root dehydration. When mulch compacts over time oxygen is unable to reach the tree’s roots.
So not only can the roots begin to girdle, but as the mulch degrades and roots are exposed, they become dehydrated from being at the surface where the mulch was.
Have you ever spread mulch on a hot day, when the mulch has been sitting in the sun? When you pile mulch against the trunk of the tree you’re trapping all of the heat and moisture against the trunk itself, creating a perfect environment for bacteria and pests to thrive.
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Makes The Tree Vulnerable To Pests And Insect Damage
How might this cause a perfect environment for pests even? Because of the slow but intense effects of volcano mulching, the tree becomes stressed and isn’t as strong to protect against insects who attack trees when they are weak.
The effects of burying the base of a tree with a mulch volcano are not immediate. They are long-term effects that happen over time. So even if you have done it, or seen it, and don’t see any issues with your trees, it’s because the damage is taking place slowly!
Fertilizers are essential to getting a tree back to its former glory once issues start taking place. It’s also a great idea to consult a local arborist if your tree already has pest damage!
What Can I Do Instead Of Burying a Tree Base?
Mulching around the base of the tree is a great way to keep moisture in, help regulate soil temperature, and improve the soil content.
If you created a mulch volcano unknowingly, don’t worry, you can fix it!
Rake Away Excess Mulch
If you’ve already put too much mulch around your tree, you should rake away the excess mulch to create a circle around the tree.
You only want the mulch to be 2-4 inches deep. Also make sure the mulch doesn’t come close to the base of the tree, roughly 4-6 inches away from the trunk.
It’s fine to not have any mulch against the trunk. And, it’s better for the tree plus allows for the exchange of oxygen, water, and nutrients.
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Make sure to rake the mulch out to the drip line of the tree, which is where the canopy extends to. The shape will probably take on a circle, which is aesthetically pleasing and the general shape the drip line creates. And that’s it!
Create A “Mulch Circle” Around Your Tree
When you do create a mulch circle around your tree, you want to think of making it look like a donut shape.
This means you’ll want to keep the mulch away from the trunk (the hole in the donut) and pull it out evenly to the drip line (the main part of the donut). Creating a donut out of mulch can help you remember to keep that mulch away from the trunk! No matter how tempting!
Use this technique for all plants, trees, and shrubs alike!
If you haven’t mulched around your plants or tree yet, you can use the mulch donut shape to correctly mulch around your tree instead of burying your tree base.
But again, don’t put mulch against the base of the tree, and make sure it’s only a few inches deep, preferably, 2-4 inches, and no deeper!
Why You Should Always Mulch Your Tree
Now that we’ve gone over the proper way to mulch your tree instead of burying it, we’re going to talk about the benefits of mulching your tree and plants.
Increases Soil Composition
First off, mulching around young trees is one of the best things you can do for your tree! It helps increase the tree’s growth rate, decreases competition from surrounding plants, and helps to improve the moisture content in the soil.
But, the benefits don’t stop there!
Reduces Watering Frequency
Mulching your tree can help reduce the frequency of watering your tree, saving you time and money.
Mulching also increases the amount of organic matter and adds an extra layer to the soil, which helps to reduce erosion and protect the integrity of the soil.
Mulch Can Double The Growth Rate Of Your Tree
According to information from Kansas State University, the growth rate of your tree can double just by adding mulch. Of course, this is done by “properly” mulching your trees consistently.
If you follow our tips above, you’ll be in good shape because you’ll be putting your tree in a great spot to grow moving forward!
Prevents The Growth Of Weeds
Mulch also prevents weeds from germinating and reduces the growth of weeds.
So, no more need for going out and hand picking all those weeds under your tree! Well, you’ll probably still have to pick some out.
Did you think that the benefits of mulch stopped there? Well, think again, they just keep going!
Reduces Salts And Pesticides That Can Reach The Trees Roots
Mulching also can reduce the number of salts and pesticide contamination in water, and it is known for binding to heavy metals.
According to the University of California Cooperative Extension, mulch helps dilute the number of salts that are deposited in the soil because it traps evaporation. Additionally, organic mulch can degrade pesticides and other types of contaminants like heavy metals.
Organic mulch is made up of things that decompose naturally and is made of plant material. This could be straw, old hay, pine needles, cover crops, wood shavings, compost, leaves, wood chips, and bark chips, to name a few.
This contrasts with inorganic mulch, which doesn’t break down naturally, like plastic, rubber chips, or anything of the sort.
Best Simple Mulch To Use For Your Tree
Before mulching, you’ll want to choose the right mulch for your yard and garden.
If you’re not sure where to start with organic mulch, pine straw mulch is a good option. The USA Pine Straw – Premium Pine Needle Mulch covers up to 160 square feet at a 2-3 inch depth. It helps suppress weeds and is lightweight.
Pine straw mulch is significantly lighter than wood mulch, which might be the right option if you’re looking for something that’s not as heavy as regular mulch.
Pine straw mulch is also less expensive than regular mulch, and it is a good insulator. Like most mulches, pine needle mulch keeps moisture within the soil and is best at preventing weeds. Additionally, pine straw doesn’t need to be replaced as often as other mulches.
That’s A Wrap
So, do you still think you want to create a mulch volcano? After reading this, hopefully, you’re cured of piling mulch up against the tree trunk! Let’s recap why you shouldn’t bury a tree base.
- When you bury a tree base, you are setting up the tree for lots of issues. These issues aren’t immediate, happen over time, and can surely destroy your tree to the point of no return.
- Burying the base of a tree and creating a mulch pile or volcano against the trunk restricts vascular flow to the rest of the tree. It causes root girdling around the trunk of the tree preventing water and nutrients from getting to the rest of the tree.
- Burying the trees base also causes root dehydration and prevents oxygen from flowing to the roots. Not only this but when you create that mulch volcano against your tree trunk you’re creating the ideal environment for pest infestations and rot!
But in case you have trees in your yard that have mulch volcanoes, no need to worry, you can fix it! By raking the mulch away from the trunk of the tree and into a donut shape towards the outer edge of the canopy, you’ll have corrected your mulch volcano.
Thanks for sticking around and we hope you learned why you shouldn’t bury a tree base! Happy mulching!
Gilman, Edward F., and Jason Grabosky. “Mulch and planting depth affect live oak (Quercus virginiana Mill.) establishment.” Journal of Arboriculture 30, no. 5 (2004): 311-317.
Kamara, A. Y., Akobundu, I. O., Sanginga, N., & Jutzi, S. C. (2000). Effect of mulch from selected multipurpose trees (MPTs) on growth, nitrogen nutrition, and yield of maize (Zea mays L.). Journal of Agronomy and Crop Science, 184(2), 73-80.
Koski, Ronda, and William R. Jacobi. “Tree pathogen survival in chipped wood mulch.” Journal of Arboriculture (2004): 165-171.
Mulumba, L. N., & Lal, R. (2008). Mulching effects on selected soil physical properties. Soil and Tillage Research, 98(1), 106-111.
Prosdocimi, Massimo, Paolo Tarolli, and Artemi Cerdà. “Mulching practices for reducing soil water erosion: A review.” Earth-Science Reviews 161 (2016): 191-203.
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