How to make mulch rings around trees

The Ultimate Guide to Mulching Around Trees

Whether you have a newly planted tree or a mature tree in your landscape, laying down a thick layer of mulch is a wonderful yearly practice that can dramatically improve the health of your tree long term.

When you’re planting a new tree in your yard your first step is to choose the right tree for the location, the second step is to plant it correctly, the third step is water it regularly and the final step is to spread mulch around the tree. Older trees can also benefit from a layer of mulch around their base.

In this article you’ll learn the many benefits of mulching, best practices for putting mulching around trees, the best types of mulch to use and where to source it. Oh, and how to avoid mulching volcanoes!

Benefits of Mulching Around Trees

Next to watering, mulching is arguably the best practice for keeping newly planted or even older, established trees healthy long term. 

What is mulch? Mulch is an organic material spread on the soil surface to protect the soil and tree roots from from things like heat, cold, and drought. As it breaks down mulch also improves the soil around the tree.

Mulching benefits include:

  • Decreased evaporation: Covering the soil helps it retain more moisture for the roots to uptake.
  • Root insulation: A layer of mulch moderates the temperature of the roots, keeping them cooler in the summer and warmer in the winter.
  • Air exchange: Mulch allows for more gasses to reach the roots, which improves respiration.
  • Improves soil structure: Mulch breaks down slowly over time and becomes rich humus. Humus increases soil nutrients and organic matter in the soil.
  • Decreases root competition: You don’t want grass and other plants popping up at the base of your trees because they compete with the tree for water and nutrients (and often win!).
  • Protection from lawnmower damage: If you walk around any city or town and look closely at trees planted in grass you’ll notice that many of them have wounds low down on their trunks from being run into with lawnmowers and other equipment. A nice, wide mulch ring will ensure you never accidentally run into your tree causing damage.
  • Dang it looks good! Mulch rings lend a tidy and aesthetically pleasing appearance to your landscape.

How to put Mulch Around a Tree

We recommend using woodchips as mulch for your trees. Medium to coarse textured woodchips work best, as fine material (eg: finely shredded bark mulch) can pack down and inhibit water from reaching the roots. Avoid rubber mulches and rocks if possible.

Woodchips are available for free in many municipalities. If you’re having tree work done on your property you can request to have the woodchips dumped in your driveway.

If you have many trees to mulch and a big garden you could sign up for a service called Chip Drop. You submit your name to a database that tree care companies can search when looking for somewhere to get rid of a load of woodchips. Our dump trucks fill up several times a week and we’re always looking for places to deposit woodchips and clear out our trucks for the next job.

Once you have your load of woodchips and are ready to mulch there are a few tricks and tips to keep in mind for applying mulch around a tree.


Always mulch 2-4” deep, never greater than 4” deep. Mulch that is too deep can inhibit the oxygen exchange that needs to happen between roots and the atmosphere. In other words, roots breathe oxygen just like we do! Most of the roots of a tree are located in the top 6-24 inches of the soil, so make sure you’re not covering them up with too thick of a layer of mulch.


The wider the mulch ring the better. We suggest 4-6’ or greater from the trunk of the tree. The farther out you can spread the mulch ring the better for the tree because the less the roots have to compete with grass for water and nutrients.

Roots stretch wider than the canopy, so give them room to breathe! It’s especially helpful to have a large mulch ring around young trees. The growing roots will thank you!

Make sure you leave the root flare (base of the tree) slightly exposed. Aim for flat round mulch rings, like a donut, and avoid “volcano mulching,” or piling mulch up against the trunk. More on that later.


We suggest a natural edge. If you dig a 2-4” deep trench around the outside of the ring, the mulch will naturally fall into it. No need for plastic edging!

In fact, when roots hit the plastic edge they interpret it as a barrier, and begin growing in a circle. This can lead to girdling roots (pictured left).

say no to volcanoes!

While walking around your neighborhood or town you might notice the strange phenomenon of people creating tall piles of mulch around their trees, or what we like to call “volcanoes”.

This great illustration from Trees Louisville shows the difference between a mulch ring and a volcano.

Illustration courtesy of Trees Louisville here.

As you can see in the first illustration of proper mulching, the mulch is pulled away from the base of the trunk. You can build it up a bit higher around the perimeter in order to create a basin for the water to infiltrate the soil.

The picture on the right illustrates the shape of the volcano style of mulching, which is a big no-no! Mulch that is piled up against the trunk of the tree traps moisture against that area which can lead to rot and decay. It also provides a home for insects and rodents which will sometimes eat away at the bark.

When you’re mulching your trees keep the above images in mind – wide, flat rings like a donut, no volcanoes!

Investing some money for mulch and a few hours of labor each season can help your tree thrive for a lifetime. Did you make a beautiful mulch ring? Neighbors might find it strange to get excited over a mulch ring, but we get it! Email us a photo at [email protected]! Show off that beautiful donut. 

How to Mulch Trees

How to Mulch Trees the Right Way

Return to Trees and Shrubs Agent Articles

We all have our soap box issues. They can range from the little things that just get under our skin to major life changing concerns. Lately for me my horticulture soap box issue has been tree mulching, or should I say the horrific practices I see that have been heaped upon helpless trees in our landscapes. It just slays me that people can mess up something so simple so badly!

Value of tree mulching
Creating a mulch ring around a newly planted or young tree less than 10 years old is the single best practice that can be done once the tree is planted. Tree mulching provides so many benefits, most importantly increased growth. Everyone wants a fast growing tree and proper mulching is the key. Research has proven that, over time, a mulch ring placed 3 to 6 feet around the tree can almost double the growth rate of the tree.

Mulching decreases competition from the grass. Grass robs water and nutrients from the tree’s root development and delays its establishment. A properly placed mulch ring helps conserve moisture and cools the soil aiding in root growth. Lastly, the other main advantage to mulch is it keeps our lawn mowers and weed whips away from the tender trunks. It is amazing how many landscape trees have been compromised by having chunks of bark knocked off in our zest to whack back every single blade of grass.

How not to mulch a tree
Unfortunately you can look on just about every street corner and see examples of what not to do. Tree mulching is not heaping piles of mulch up and around the trunk. Mulching is not developing a volcanic cone of wood mulch a foot or more high right up against the trunk. I have no idea why anyone would think placing piles of mulch up next to the trunk could be beneficial to the tree.  

Mulch heaped onto the trunk of the tree will result in a shortened life expectancy, or even death. Mulch that touches the trunk is moist from rainfall and irrigation. Over time this moisture rots and decays the bark layer of the tree, which kills the cambium layer area of tree growth and eventually rots the heartwood of the tree.

Deep piles of mulch, over 4 to 6 inches deep also excludes oxygen from the soil. This results in root development up into the mulch layer, not down into the soil. These so called surface or mulch roots do little to support the tree in the long-term for robust growth.

How to mulch a tree
I have always said when it comes to mulching trees think about donuts and bagels. What is in the center of these breakfast foods? A hole! This hole in the center is where the tree trunk would be located. Proper tree mulching starts out about 3 to 6 inches from the trunk and continues out in all directions at least 3 feet. Six feet would be even better for long-term establishment and increased growth.

The thickness of the mulch layer should be somewhere between 2 and 4 inches deep, or thick. It does not take piles to accomplish the benefits of mulch. A properly mulched tree should appear to have just a slightly raised ring around the tree.  

Over time the mulch will blow up next to the trunk and breakdown. This means that as part of normal maintenance the mulch ring should be replenished yearly. Start by carefully pulling the mulch back from the trunk, and then add enough new mulch to the 4 inch depth.

Types of mulch
The best mulch for trees is organic wood chips. There are a number of different wood chip products which all accomplish the desired outcome of improved tree growth. Select which type of mulch fits your budget and desired appearance. Raked leaves are just as effective as the trendiest designer dyed mulch on the market. Wood mulches will not transmit insect and diseases to the tree. Any harm associated with wood chips comes from improper mulching practices. Keep in mind, mulch serves a function. Its secondary aesthetics is only important to one’s personal taste. The tree really does not care.

Mulching young trees is more important to overall establishment and growth than fertilization or other practices. The removal of the sod and creating this zone of root development will help develop a healthy tree. Don’t follow the bad examples done by many grounds maintenance firms and unknowing neighbors. Join my soap box and spread the word about the importance of correct tree mulching for success.

How to mulch tree trunks

Tree roots need regular watering, feeding, protection from drought and frost. Mulching the trunk circle is an effective way to preserve moisture and nutrients in the soil, suppress weed growth, and protect roots in winter. Mulch components enrich the earth with organic residues, prevent erosion, soil erosion, attract worms and beneficial insects.

With so many mulching materials, it can be difficult to choose the right ones for mulching the soil around trees. The choice of this or that material depends on the desired result: protection from heat and cold, soil nutrition, garden decoration.

Types and properties of mulch for trees

All types of mulch that are used in home gardens are divided into 2 types: organic and inorganic.

Organic mulch is based on processed natural materials. Its important property is the enrichment of the earth around the trunks with nutrients. Coniferous needles, cones, sawdust, bark, branches, straw, hay, rotted manure and compost are used to cover the trunk circle of trees.

Needles improve soil ventilation, drainage, repel rodents, increase soil acidity. The resins contained in it slow down the metabolic processes in the soil.

Sawdust, bark, wood chips, small branches improve soil aeration, increase its acidity, retain moisture and snow, and prevent nitrogen penetration into the soil. They are used after two years of exposure to sand and nitrogen-containing fertilizers.

Hay, straw, cut grass rot quickly, supply the soil with organic matter, contain plant seeds. Small rodents and insects often start up in hay, which harm trees.

Compost is organic remains of sawdust, wood shavings, leaves, wood chips, vegetables, and fruits that have rotted for two or more years. It is considered the best type of natural mulch.

Inorganic mulch does not rot. It is reusable and has protective and decorative properties. These are stones, pebbles, gravel, crushed stone, broken bricks, agrofibre, paper, cardboard. These materials do not feed the soil, but retain and pass moisture, improve the appearance of the site, and prevent the growth of weeds. To feed the roots, inorganic mulch is removed from under the trees, tree trunks are fertilized, loosened, and then returned to its original place.

Features of the use of mulch

For coniferous and fruit trees that do not require organic top dressing, use inorganic mulch. It suppresses the growth of weeds, passes moisture to the roots, creates an attractive appearance of the site, protects the roots from frost. In the near-stem circles of such trees, bright flower beds are broken, which do not require careful maintenance, create a good mood.

Needles and waste from wood processing increase the acidity of the soil. They cover the soil around the apple tree, quince, dogwood, which give a high yield on acidified soils. Plums and cherries grow well on neutral soils, so they should be carefully mulched with needles and sawdust. Alkaline soil is loved by tall and white plums, mountain ash, yew berry, viburnum, so needles and wood chips are not suitable for them.

Organic materials are used to protect and fertilize the soil around trees. Decomposed compost, manure is the perfect mulch for this occasion.

Rules for mulching near-stem circles of trees

Usually, near-stem circles are covered in spring, when the soil around the trees has already warmed up, dried up, and the first shoots of weeds have appeared. First, they clean and burn last year's organic mulch, in which insects, rodents, putrefactive bacteria have taken refuge for the winter. Then they loosen, fertilize the near-stem soil, pour fresh mulch. The diameter of the circle should be approximately equal to the diameter of the tree crown.

The effectiveness of mulching depends on the thickness of the layer. Too thick a layer will lead to decay, too thin - to the development of weeds and loss of moisture. The optimal thickness is 3–7 cm. The heavier the soil, the smaller the mulch layer. The height of the layer depends on the type of material:

  • needles - 3–5 cm;
  • sawdust, shavings - 3–7 cm;
  • bark - 3-5 cm;
  • hay, straw, grass - 7-15 cm.

Too early spring mulching slows down the awakening of plants from hibernation. Mulching immediately after heavy rains is not recommended, because pathogenic microorganisms, fungi, slugs quickly develop in dampness. Not rotted manure and compost causes burns and death of young seedlings.

Autumn mulching is carried out in regions with cold winters to protect the roots from freezing, to delay the snow cover around the trees. It is impossible to lay a layer of mulch on frozen ground.

Proper application of mulching improves the growth and yield of trees on the land. This is an effective way to protect and decorate the garden.

How to make an annual ring mulch

Properly built mulch growth ring will not only enhance the beauty of your yard, but it will also enhance the overall health of your trees. Mulch is a protective covering, either organic or inorganic, that is spread over the ground to improve plant growth, reduce moisture evaporation, and stop weeds from growing.

Step 1 - Choosing the Right Mulch

Organic mulch, such as wood chips, straw and pine needles, makes an excellent, natural tree fertilizer because it slowly breaks down to feed the soil. As such, a ring of mulch around trees not only looks attractive, it also protects the tree's bark from lawn mower or weed trimmer damage. Mulch has many benefits. In addition to improving the soil, mulch also retains moisture; controls weeds; reduces soil compaction and prevents erosion. Unlike synthetic mulches made from recycled rubber or plastic, because organic mulch breaks down and improves the underlying soil, it eventually needs to be replenished.

Step 2 - Prepare the soil

The best way to mulch around your trees is to create a ring of mulch at least 4 to 6 feet in diameter around the trunk of the tree. The more surface area covered in the mulch, the better for your trees. Start by placing a circle of wet newspapers around the tree trunk. This will help prevent any weeds from poking through the mulch. With the tree already established, use a weed trimmer to cut the grass as close to the ground as possible. If the ground is extremely weak, use a brand name weed killer. However, use this only as a last resort to insure the continued good health of your trees. Do not use a commercial weed block or any other types of fabric. Weed blocks or fabric could prevent organic matter from enriching the underlying soil. Further, the fabric also prevents beneficial organisms such as earthworms from living in the fabric-covered soil. This can cause serious problems for the tree if enough of the root zone is covered.

Step 3 - Measure Mulch Depth

With a trowel, spread the mulch under the trees to a depth of 2 to 3 inches. Trees are very sensitive to the depth of the mulch around them. If the mulch is too deep, rain and moisture will be unable to penetrate to the existing root system.

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