Understanding how to mulch a tree and shrub will help you guide your tree to optimal health for years to come. Mulching around your tree is one of the easiest, quickest, and most cost-effective things you can do to support it.

Why Mulch is so Good for Trees

Here’s a quick rundown of why it’s important to know how to mulch a tree:

Benefits Of Mulching:

• Enhances root growth which improves overall tree health
• Nearly doubles the growth rate of newly planted trees
• Can create a buffer between temperature changes
• Helps retain root and soil moisture
• Protects against root competition and soil compaction
• Helps tree soil retain its essential nutrients
• Reduces lawn mower damage

When is the Best Time to mulch around trees?

While mulch can be applied to your trees at any time of the year, the best time to mulch is in the spring season. Certified Arborists and tree service experts alike generally recommend that you mulch around trees in mid-spring, when the temperatures consistently stay warm.

The Consequences of Improper Mulching

• Increases susceptibility to insects & diseases caused by mulch irritation on the trunk of the tree.
• Girdling Root Systems – a condition where smaller roots wrap around a dominant root. This chokes the tree, which makes it absorb essential nutrients it needs to survive.
• Rodent issues – mulch piled high against the trunks of trees creates habitats for rodents that chew the tree’s bark.
• Root Rot from excess moisture

In our Northern VA, MD, and DC tree service area, we, unfortunately, see a lot of improper mulching practices. In this article, we’ll guide you through how to mulch a tree; this way, you can avoid making the top 5 mulching mistakes.

The Best Ways to Mulch Around Trees

How wide should mulch be around trees?

The best mulching goes out as far as the tree’s canopy, referred to as the drip line of the tree.

Mulching this far out covers the tree’s “life veins” (“critical root zone”/CRZ). By doing this, you’ll apply the mulch where it matters most (where the feeding and nourishing happens).

Most homeowners don’t like to apply mulch around trees in this way. They either don’t like how it looks, or they have big trees on small properties.

If mulching this far out isn’t practical, you can apply mulch in a 2 to 3-foot radius around the tree.

How much mulch should I use for my trees?

You should apply mulch about 2-4 inches deep. Most mulching you see is likely a lot deeper than this, as over-mulching is one of the most common mulching mistakes.

It’s become a common practice to pack 6-12 inches of mulch up around the base of the tree; however, this over-mulching is very bad for your tree and can result in the many issues we discussed earlier.

Avoid mulch volcanoes!

Need Help With Soil & Root Care?

Our Top Tips for Mulch Application Around Trees

Keep Mulch Away From The Tree Trunk

Do not pile the mulch against the trunk of the tree, as this can cause the roots to grow in a way that causes them to choke each other. Instead, keep the mulch away from the trunk, so that the root flare zone (shown on the right) is visible.

Remove Last Year’s Mulch

If you want to refresh the mulch, don’t pile the new layers on top of the old. Instead, lightly rake the top layers of the mulch, or remove the old mulch and replace it with fresh mulch.

Don’t Use Fresh Wood Chips For Young Trees

Do not use fresh wood chips for mulching around young trees, as they can injure the tree.

Pine Needles are an Affordable and Effective Mulch Alternative

If you have a healthy pine tree, you can save money by opting for pine needles. They typically last longer and are more durable against harsh weather. Avoid using them if wildfires are frequent in your area, as pine needles are flammable and can easily ignite a fire.

Yes, You Can Use too Much Mulch

Adding too much mulch around a tree and committing the ever-too-common mistake of building a mulch volcano will actually be too much of a good thing. Too much mulch can lead to poor soil and root health, leading to tree decline.

How to Tell if Mulch is Correctly Applied

As you can see, it’s crucial to understand how to mulch a tree. After all, 80% of tree health issues are connected back to the tree’s roots, so it’s vital for them to be in tip-top shape.

Quick Tree Care Tip From A Certified Arborist:

A quick and easy way to check how well your tree is doing is to push on the tree trunk and then look down at the tree’s root crown (pictured at the right).

If this area heaves up or if your tree seems to rock when you push down on it, then you’ll want to have your tree checked as it may have girdling roots.

*IMPORTANT: If GRS (girdling root syndrome) is not addressed and resolved immediately, your tree will experience chronic decline over time.

How to Recover from Incorrect Mulch Applications

If you have just recently over-mulched your tree, you can simply go out and fix it. You can redistribute the mulch to best support your tree’s needs, as long as you follow the instructions above.

But, if you’ve accidentally been over-mulching your tree for years, or you have other concerns for your tree’s soil and root health, you will want to turn to your Certified Arborist for help.

To improve your tree’s soil and root health, you can:

• Have your Certified Arborist assess your tree’s roots: Through root collar excavation, your tree service expert will be able to open up and assess the tree’s root zone to see if it may be experiencing girdling roots or root rot.
• Ask about our root care package: If your Certified Arborist discovers underlying root issues, don’t worry. We have a root care package that will help you supply your tree with the essential nutrients it needs and is likely missing from its urban environment.
• Apply the best organic multivitamin: Our Certified Arborists like to say that if you can do one thing for your tree, it’s to apply biostimulants. Biostimulants are an all-natural, organic solution that nourishes your tree, strengthens its immune system, and can help your tree and its root system recover from poor root and soil health.

Consult with an RTEC Arborist Today!

If you need help with your soil and root care this spring, you can reserve an appointment with one of our Certified Arborists through our online booking system or by calling us at 703.573.3029.