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What is Mulch?

Mulch is a layer of material applied to the surface of the soil. Mulch is usually, but not exclusively, organic in nature; meaning that it is derived from living matter.

Generally, organic mulch is obtained from various plants and trees and can be a specific component of the plant (the protective bark, branch and trunk matter, leaf material) or a combination of some/all these materials.

Why should you Mulch?

Mulch can serve both a functional and aesthetic purpose in your garden or landscaping project.

To make an informed decision on which mulch to use it is important to establish the main reasons to mulch. These can range from

Adding colour to enhance the visual impact of your garden.
Enriching the soils used for growing vegetables and plants.
Preventing excessive evaporation and crusting of soil that causes hydrophobic soil.
Moderating soil temperatures to reduce stress on plant roots.
Weed suppression.
Reducing water usage in your gardens.
Reducing erosion on banked areas.

What are the various mulches on the market?

The various mulches and wood chip on the market offer different characteristics to meet different requirements. To make matters more complicated, various mulch outlets can label mulches with different names but it’s actually the same product. The best way to stay informed is to find out where the mulch is sourced from.

Mulch falls into 2 categories – Recycled off-cut material and processed material.

Recycled material is usually cheaper but has been repurposed through a basic grinding or chipping process utilizing a mix of whatever trees were available, therefore it lacks consistency and is not very refined.

Processed Mulch is a result of a single type of tree that has gone through a regulated manufacturing process to ensure consistency and quality.

Let’s look at mulches on the market.

Forest Mulch.

This is a heavy, coarse product that is produced by putting whole trees (usually a result of land clearing) through an onsite grinding machine. As a result, it can contain site rubbish and soil.

Leaf Litter.

Generally a mix of branches, trunks and leaves that has been put through a tree-lopper’s wood chipper machine. A lighter mulch, it will vary depending on the type of trees that have been felled at the time. It can also be called Forest Mulch or Budget Mulch.

Hardwood Chip or Pine Chip.

As the name suggests, this is a by-product from timber yards processing either hardwood or pine timber. It is usually 30 to 60mm sizing but, being it is a by-product, size cannot be regulated. Always ensure the timber being used is not chemically treated as it can be harmful to your plants.

Slash Bark or Pine Bark.

Also referred to as Tan Bark. Derived from the bark of the slash pine tree, Slash Bark is solid, chunky, dark in colour and can come in various sizes including 2 inch (50mm), 1 inch (25mm) and 10mm (known as Soft Fall, which must meet Australian Standards for use in playgrounds).

Hoop Pine.

Also originating from the protective layer of pine trees, Hoop is made by grinding the bark to produce long, curly strips mixed with some finer particles.

Fines.

Fines are simply the smaller particles of any mulch that have been screened to be separated from the larger components. Naturally, being smaller in nature, they break down quicker and are great for use as a ‘food-source’ for your soil. Products on the market include Forest Fines, Budget Fines, Hoop Fines.

Cypress Mulch and Tea Tree Mulch.

Both mulches are classified as ‘Termite-Resistant’ as they contain resins that termites dislike. These mulches generally go through processing procedures so they tend to be more consistent and a better quality which makes them great decorative mulch as well.

Coloured Mulch and Chip.

These products have a coloured dye added during processing to give the mulch a vivid finished colour. The most popular colours are Red and Black as these create a contrast ‘pop’ with your plants.

Sugar Cane Mulch and Lucerne Mulch.

These are leftovers after the plants have been processed for other uses. They are usually available in loose bales or compressed into sealed bale packaging and are great for vegetable gardens as they feed sweetness and nitrogen into the soil.

So how do I choose a mulch that’s right for me?

The first step is to establish what is the purpose of your garden. If you are growing veges or ornate plants, the focus is to maximize your growing media by using mulch that breaks down and feeds the soil (Sugar Cane, Lucerne, Compost) Otherwise, if your garden is a decorative, low maintenance part of your landscaping, something that addresses these needs would be preferable. Things to consider when choosing a mulch or wood chip.

Colour matching to suit design.
Layout of area. Binding mulches or course mulches such as Hoop or a blend are better suited to steep inclines as they hold their position better than a chip product.
Cypress Mulch offers termite resistance.
Dye-coloured mulches like Cypress Uluru Red add a fantastic colour ‘pop’ to augment your landscaped area and vividly contrast green, leafy plants.
Sugar cane & Lucerne mulch are great for topping vegetable gardens. Not only does this prevent evaporation and potential ‘crusting’ of soil which can prevent water permeating the soil, it breaks down and feeds sweetness and in the case of Lucerne Mulch, nitrogen into the soil.
While mulches offer a certain amount of weed suppression, it is recommended to use weed mat or mulch mat as an added barrier.

It is important to remember that Organic Mulch, by nature, will eventually break down. The rate of decomposition is dependent on the structure of the mulch (dense hardwood chip will take longer to break down than fine shreds or leaf matter) and the environment it is placed in (Temperature variations, moisture etc)

Of course, your budget will play a large role in your mulch selection. It is wise to incorporate mulch into your landscaping budget from the outset, otherwise you may end up spending the majority on soils and plants and have little left for mulch as it is the last component of landscaping gardens. However, consider mulch as the insurance investment you need to ensure your gardens prosper. Mulch pricing can range from around $25m3 to $150 m3 and while budget restraints can factor into your decision, choosing the best mulch for your purpose will prove more cost-effective in the long run.