How to mulch your trees the right way

Learning how to mulch your trees the right way is easy! Tree care can be rewarding as well as fun but often it is the simplest things that can have the greatest impact.

Mulching around your trees is a simple and easy way to care for them, giving them many benefits.  From controlling weeds, protecting plants from extreme temperatures, aiding in moisture retention and improving soil quality.

Trees evolved with a symbiotic relationship with fungi in forests where they had the ability to use the fallen leaves and decomposing material to enable growth and survival.

Urban trees have to contend with depleted soils, mown lawns, concrete footpaths and paths, roads, cars and humans stomping on their root plates, etc.  They need all the help they can get as our urban environment drastically reduces the water and nutrients available to the tree.

Most people focus on what’s above the ground when caring for their trees.  Just as important, if not more so is what’s going on beneath the soil.  This is where trees get their nutrients from and what has the biggest impact on the overall health of the tree.

Continue reading for tips on how to best apply mulch around your trees.

Why is mulching beneficial?


It helps to control weeds by acting as a barrier between how much light can pass through it.

Using fresh mulch can help you control weeds.
Mulch and cardboard can be used to control weeds

Moisture retention:

It assists in retaining moisture and preventing evaporation by blocking out the sun from the soil therefore stops the soil from drying out.  It also decreases the water run-off during our rainy days or when watering and this reduces the amount of water needed, potentially (and in the near future) saving you money!

Provides insulation:

It improves insulation for the roots whether it is the hot summers or freezing winters, mulch protects the roots of trees and plants in your garden by acting like a coat. Newly planted or young trees that are yet to develop their root system will particularly benefit from this protection until they become strong enough to withstand our crazy weather.

Improves soil quality:

Mulch is amazing for soil as it helps increase biological activity by providing beneficial earthworms, fungus and microorganisms with food. As mulch decomposes it adds nutrients to the soil. If the microorganisms and soil fungi are in good health, this generally relates to good tree health. It is also a great way to bind together sandy soil or open clay soil.

Healthy looking soil can be generated using good quality aged mulch which encourages worms, good fungus and microorganisims.
Soil should be alive with micro-organisms

Saves you time and $$$:

It can save you time (by retaining moisture = less watering) and money. Why pay to get rid of your green waste when you can add it to your mulching pile and recycle waste material (such as grass clippings, fallen leaves, etc.)

Aid in visual amenity:

It can tidy and beautify your garden by providing uniformity to landscaping features. It can make an old plant look fresh and newly planted, and it brings a tidiness, precision and elegance to the landscaping.

Mulched gardens look fresh, healthy and tidy.
Mulch around your trees and plants is super beneficial – as long as you don’t over do it and smother them

Our top tips for mulching your trees is below:

Use good quality aged tree mulch.

As mulch breaks down it releases nutrients that can be absorbed by the trees at a rate they can deal with.
Fungi is also provided for in this process which is important given that fungi has a relationship with the tree’s root system.
Good quality mulch mimics the forest floor environment.  This encourages health and growth.
Earthworms are drawn to a mulched area and they get to work to naturally aerate and improve the soil around your tree.

Good quality aged tree mulch should have a combination of green leafy matter and bark/wood chips. A solely bark mulch (as some people like to use for an ornamental look) actually pulls nitrogen from the soil as nature attempts to break it down.

Mulch will be ready for use around trees and plants (not weeds) when it has stopped steaming, is cool to put your hand into, brown in colour and smells earthy.
Mulch will be ready for use around trees and plants (not weeds) when it has stopped steaming, is cool to put your hand into, brown in colour and smells earthy.

Let mulch age.

If you are using mulch around your trees and plants to encourage growth and help keep them and the soil healthy, you need to be using cool, good quality aged mulch.  Letting the mulch age allows it to start breaking down.  The mulch being used should NOT be steaming when it is turned over and should be a dark brown colour.
The ageing process begins as soon as the tree/branches are chipped.
Yes, you can add fresh lawn clippings to your compost pile but as above, let it age as part of this process. Do NOT add fresh lawn clippings around your tree – this will generate heat as it breaks down and create acidic conditions.

Aged mulch should be a brown colour and include green leafy matter as well as wood.
Aged mulch
Fresh mulch - colour will depend on the type of tree
Fresh mulch – colour will depend on the type of tree
Good mulch will have a combination of green leafy matter and wood
Good mulch will have a combination of green leafy matter and wood

Clear the trunk and root plate.

Clear the grass and weeds away from around the trunk of your tree before laying down mulch.
Competition no matter how small is still competition.
Using a paint spray can, mark out a circle around the tree giving it as much space as possible (out to the dripline if possible). Grab your spade and push it into the grass around the circle (don’t go too deep as to damage or cut roots) and remove slabs of grass from above the roots.

This space is now ready to add compost, fertiliser and mulch too.

Please note: I don’t use this method in an orchard. Instead, mow the lawn, cover the lawn with cardboard (removing the sellotape and stickers first) and pile a thick layer of good quality mulch on top (20cm or more).

Give the tree space!

Give the tree as big an area as possible for mulch as the roots of the tree generally reach at least as far as the outer leaves.  This is called the root zone and you will find small, newly forming roots in this space.  Giving a bigger space also means you don’t need to weed or mow around the trunk, therefore protecting the tree from damage from the weed eater or lawnmower.

Mulching the root zone, NOT the trunk.

Pile the mulch around the tree’s root zone in an even layer at least 100mm high.  Too little mulch and you won’t realize any benefits, too much and it stops the trees ability to breath through their roots.

Important tip: Do NOT pile the mulch against the trunk of the tree or stalk of your plants.  Like us, trees breathe and some of their ‘breathing holes’ are located in and on their trunk.  If you pile the mulch against the trunk, this inhibits the trees ability to breathe and you are more likely to suffocate it and eventually cause damage.

Mulch placed correctly around a tree trunk
Mulch the root zone, not against the trunk

Top it up!

Check the mulch every change of season and add more as it breaks down.  A great idea would be to have a pile of mulch located in the corner of your garden decomposing so you can use it as needed.

The last point to remember is that using fresh mulch can burn your tree trunks and roots as well as the stems of your plants.  This may damage them.
All is not lost!  Weeds can be controlled by using fresh mulch!  If you want to get really serious, lay cardboard down and mulch on top of that.  Make sure to remove any labels or tape from the cardboard first.

We provide a tree care service and are more than happy to provide you with a free no-obligation quote. Contact us today and we’ll book you in for a chat.

Happy days, happy mulching, happy trees!

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