Sometimes it’s tricky to tell what’s too much, not enough or just right for our trees.

Take mulching, for example. It’s a must for proper tree maintenance, but when mulch is too high and touches a tree’s trunk, it can cause problems.

Let’s look what can happen when you apply mulch that’s too thick around trees.

When is mulch around trees bad?

To be clear, mulch is great for trees (when it’s applied correctly). Mulch reduces weeds, conserves moisture and improves the soil, which helps your tree stay healthy!

But when it comes to mulch, it is possible to have too much of a good thing. Piling mulch too high and covering a tree's trunk, also known as “volcano mulching,” can cause decay.

Problems Caused by Mulch That’s Too Thick Around Trees

When mulch is too high and sits too close to a tree’s trunk, it causes two main issues that can slowly damage your tree over time.

  1. Problem: Too much mulch smothers the tree’s roots.
    Consequence: Roots might grow up through the mulch in search of air. That can cause them to “girdle” or wrap around the trunk, which chokes the tree by cutting off its water supply.

  2. Problem: Moisture builds up.
    Consequence: That excess moisture between the trunk and mulch volcano creates perfect conditions for wood decay diseases, like fungi. Plus, deteriorating bark at the tree’s base can lead to an unstable foundation.

Luckily, preventing these problems is as easy as mulching your tree the right way.

Click here for step-by-step instructions on how to best mulch your trees!

Related Blog Posts

Mulch That Repels Bugs
Soil Care & Mulching

What Mulch is Best For Repelling Bugs?

What mulch is best for repelling bugs? Try cedar, melaleuca, or plastic mulch! Cedar is known to repel ants, moths, mosquitoes, and carpet beetles. Melaleuca is known to keep away termites. Plastic mulch deters aphids, thrips, and whiteflies.
Read More
Pine Needle Mulch
Soil Care & Mulching

Can I Use Pine Needles For Mulch?

Pine needles are handy to have all year long. When it’s time to mulch your plants and trees, consider using the needles that have fallen in your yard
Read More

Sign Up For Free Tree & Landscaping Tips! 

Subscribe to the "The Sapling," the Davey Blog's email newsletter, for the latest tips to keep your outdoor space in tip-top shape throughout the year.

Plus, receive a free instant download of our landscape seasonal checklists when you sign up!

Get In Touch With Us!

We pride ourselves at Davey Tree on providing prompt, professional and personalized service from certified arborists that live, work and engage in your community. Contact one of our Davey Tree specialists for your residential, commercial, utility, or environmental needs.

Let's Find What
You're Looking For!

Davey uses cookies to make your experience a great one by providing us analytics so we can offer you the most relevant content. By continuing to use this site, you accept our use of cookies. View our Privacy Policy for more information.