The Best Mulch for Perth Gardens – The Inside Story

How do you choose the most suitable mulch for your garden?

In this article, I’m going to answer some of the most common questions people ask me about mulch. I’ll talk you through the different varieties of mulch, how they are made and the pros and cons of each.

Frequently Asked Questions About Mulch

What is mulch?
Mulch is a layer of organic material applied on top of the soil in a garden area. Mulch helps to slow water loss due to evaporation, suppresses weeds, and adds to the area’s visual appeal.

What is mulch made from?
At Simply Soils, we supply mulches made from both recycled garden organics and forestry by-products. Interstate and internationally, mulches are made from materials as diverse as sugarcane chaff to ground-up rubber tyres!

Where do Simply Soils get mulch?
Simply Soils source our mulches from a range of reputable local suppliers. Because we are independent and not affiliated with one particular producer, we have the freedom to source the best quality products to supply to our customers. All our suppliers have years of experience in the production of mulches suitable for our Western Australian conditions.

What mulch is best for my garden?
All the mulches that we supply at Simply Soils are functionally very similar. When deciding what is best for your garden, choose the mulch that best suits the look you are going for and aligns with your budget.

How long does mulch last?
Different mulches will last for different periods of time. Mulches such as pine bark and hardwood chips will last the longest, holding their structure for up to three years. Tropical black mulch and enviromulch will last from one to two years. Karri and Peat, because it is ground so finely, will last a maximum of one year. All mulches will naturally fade to grey over time; they can be turned with a rake after six to twelve months to expose an unweathered surface.

Is mulch pet friendly?
Yes! All our mulches are pet friendly! They are free from metal contamination that could get stuck in paws. Even our red dyed mulch uses a food-safe, non-toxic colourant, so there are no issues if pets (or even kids) chew on it!

Does mulch attract termites?
No mulch does not attract termites. They generally do not like composted material and live deep within the timber, not near the surface (as in a mulch) exposed to wind, rain and sunlight.

Is mulch good for the environment?
es! All the mulches we supply are made from recycled green waste or forestry products that would otherwise be burnt. It is especially cool that with the mulches made from recycled green waste, enviromulch and tropical black, the organic material removed from your garden is processed and returned, which is a rare example of true closed-loop recycling.

How thick should you spread mulch?
For best results, aim to spread mulch at a depth of between 50-100mm. A great thickness to aim for is 75mm. Spreading at least 50mm thick is necessary for the mulch to fulfil its purpose in insulating the soil below and reducing evaporation. Additionally, a thinner layer will allow sunlight to reach the soil below and increase the likelihood of weeds sprouting.

Mulch Calculator

Calculate how many cubic metres of mulch you need to order
50mm – minimum recommended 75mm – average 100mm – generous


What are the benefits of mulching?
Mulching your garden has many benefits. Mulch helps to insulate the soil below, reducing soil temperature and slowing evaporation. This is hugely important in Perth with our long, hot summers and restricted watering schedules. Water is precious. You want it to be soaking down into the root zone rather than evaporating straight off the soil surface. Mulch additionally helps prevent weeds from sprouting by preventing sunlight from reaching the soil below. Another benefit of mulching is that it helps to reduce the erosion of soil in your garden beds due to the effects of wind and rain. Finally, mulch looks great! An attractive layer of ground cover mulch really puts the finishing touch on a garden sure to be the envy of all your neighbours!

Is there a correct time of year to mulch?
Mulch can be applied at any time of year. As far as winter jobs in the garden, there are worse ways to spend a chilly morning than spreading a steamy pile of fresh mulch!

Why not just use free mulch?
Free mulch is incorrectly sized for use in residential gardens, being far too coarse and is not composted: this means that any plant pathogens, pests or noxious weeds in the mulch are still active and can be introduced into your garden! Additionally, uncomposted mulch will draw nitrogen out of the soil as it breaks down, leaving your plants at a deficit.

Does the variety of mulch change how thick you apply it?
No, all mulches should be spread to the same thickness for them to do their job correctly. A thickness of 50-100mm works best for all mulches.

Should I use a weed mat under mulch?
Weed mat is non-essential; a thick layer of mulch prevents sunlight from reaching the soil below, preventing weeds dormant in the soil from germinating. Most weeds that germinate in a mulched garden bed are blown in by the wind after the mulch has been installed.

Varieties of Mulch Available in Perth

Hardwood Chips

Hardwood Woodchips - Simply Soils Perth WA
Hardwood Woodchips

Hardwood Chips are one of our most popular mulches. They are popular because they are uniformly sized, easy to spread, long-lasting and free from fine particles.

The advantages of these attributes are:

Uniformly Sized: The pieces have a neat appearance once installed in high visibility areas. You can definitely see these are a uniform square chip as opposed to a shredded type mulch.

Easy To Spread: The hardwood chips are light (approx 350kg/m3 depending on moisture content) and easy to shovel compared to other mulches.

Long-lasting: As hardwood chips are produced from native hardwoods, they are naturally durable in our harsh climate and will hold their structure longer than green waste-based mulches such as Enviromulch or finely ground mulches such as Karri and Peat.

Free from Fine Particles: Hardwood Chips are a true coarse mulch free from fine particles. This means that rainwater is absorbed through the mulch layer into the soil below rather than being absorbed by fines in the mulch itself. Fine particles also behave like soil, easily allowing weed seeds blown in by the wind to germinate.

These chips are a blend of different Western Australian hardwood species, including marri, jarrah and karri. Coming from mixed-species, these chips are not suitable for export use in paper production. Instead, they are sold into the local landscaping market. Hardwood chips are untreated and undyed and are naturally hardwearing and resistant to decay. When supplied, hardwood chips are a naturally attractive blend of browns, and on close inspection, you can see the variation in the colour of individual chips. As with all-natural timber, hardwood chips will fade to grey in the elements.

Lasts: I would expect the surface of the chips to turn silvery grey in approximately 12 to 18 months; however, you can turn the mulch with a rake to expose an unweathered surface if you’d like.

Product Info & Prices: Hardwood Wood Chips

Tropical Black Mulch

Tropical Black Mulch - Simply Soils Perth WA
Tropical Black Mulch

Black mulches are by far the most common mulches found in Perth gardens. They go by many names in the marketplace: jungle mulch, budget black mulch, premium black mulch, sandgroper mulch and the list goes on.

We call our version Tropical Black!

In my experience, the composition of these different mulches with their different exotic-sounding names is largely the same material – shredded green waste and screened peat.

Many people are surprised to hear that Tropical Black Mulch is undyed. Its colour comes from the screened peat in its composition. Interestingly it’s not actually a true peat moss as found overseas. Rather it’s a fine, silty, black sediment that naturally occurred in Perth’s swampy wetlands that were excavated to make way for residential and commercial developments. This peat is blended with fine limestone to neutralize its acidic pH and stockpiled for use in producing landscaping soils and mulches. The natural darkening of organic matter occurs when it is composted.

The Tropical Black Mulch looks its darkest when it is wet; when it dries out, it tends to look more charcoal grey, so I would recommend using it in reticulated areas for maximum visual impact.

Tropical Black Mulch’s primary advantages are its value and its popularity.

Relatively Inexpensive: It is relatively cheap compared to a premium black mulch like Karri and Peat.

Longer Lasting: It will also last longer because it is not so finely ground and therefore doesn’t break down quickly.

Blends Well: It is also instantly recognisable to any Perth gardener as a quality black mulch and will blend well with your existing black mulch, which you may have purchased under one of the other dozen trade names!

Product Info & Prices: Black Mulch

Enviromulch

Enviro Mulch - Simply Soils Perth WA
Enviro Mulch

Enviromulch (same as Enviro Mulch) is our most cost-effective mulch. If you need to cover a large area without breaking the bank or want to tidy up the yard for visitors, a rental inspection or a home opens: then it is definitely worth considering Enviromulch for your garden.

Enviromulch is very simply made from shredded and composted green waste. It is a great example of closed-loop recycling in that the green waste is used then recycled into the new mulch product without losing its properties during the recycling process.

Enviromulch is very different to the free stuff you may be able to pick up from your local council tip. The two primary and most important differences are:

Consistent Size: Enviromulch is ground twice, using different sized screens on the grinder to produce a material with a consistent finished size. Free mulch, on the other hand, is only ground once (called the “primary grind”) and is very coarse (like kindling sized coarse pieces), making it very difficult to achieve an even finish when installing. A twice ground material is far more time consuming and expensive to produce, but it is necessary to create a mulch fit for purpose in residential gardens.

Thorough Decomposition: Enviromulch is composted thoroughly over a period of months, with water regularly added and the piles regularly turned to ensure an even and thorough decomposition of the material. Free mulch is generally stockpiled, ready to pick up straight after being ground. The heat generated in the composting process is vital to destroy any weed seeds and plant pathogens. Don’t risk introducing noxious weeds and plant diseases into your garden by using uncomposted free mulch.

Product Info & Prices: Enviro Mulch

Karri And Peat Mulch

Karri and Peat Mulch - Simply Soils Perth WA
Karri and Peat Mulch

Karri and Peat is a perennial favourite amongst Perth gardeners. Karri and Peat is the most finely textured mulch that we sell at Simply Soils.

Karri Fines (a by-product of the forestry industry) are blended with rich, black peat. Due to the fine texture of Karri and Peat, it spreads beautifully and looks great when installed in high visibility areas.

Karri and Peat add organic matter to the soil as it breaks down, giving your garden an extra boost.

Karri and Peat’s fine texture, while it allows for a beautiful finish, means that it breaks down rather quickly.

Lasts: 1 year

Product Info & Prices: Karri & Peat Mulch

Shredded Pine Bark Mulch

Shredded Pine Bark - Simply Soils Perth WA
Shredded Pine Bark Mulch

Shredded Pine Bark is a by-product of the forestry industry.

It is produced when pine logs are de-barked to prepare them for milling into structural lumber. The removed bark is then re-ground and screened to a finished size for distribution into the landscape market.

Shredded pine bark is very popular with local governments for median strips and verges on main roads as it is long-lasting, easy to spread and tends not to blow around in the wind.

This mulch is also a great option for residential gardens for the same reasons.

Pine bark is very light and, in many people’s opinion, the easiest mulch to spread.

Great Smell: A great fringe benefit of pine bark is that it smells great!

Product Info & Prices: Shredded Pine Bark Mulch

Red Dyed Woodchip Mulch

Red Dyed Woodchips - Simply Soils Perth WA
Red Dyed Woodchip Mulch

Red Dyed Woodchip starts life as plain old boring pine chips. Pine chip is a great fibre candidate for dying as it is naturally light in colour and absorbent.

The pine chip is then blended with a food-grade, non-toxic colourant to produce the finished product. At Simply Soils, we always recommend having Red Dyed Woodchips delivered onto a tarp or soft surface such as grass.

This is because colour runoff can occur during heavy rains, which may stain hard surfaces like concrete or concrete pavers.

Red Dyed Woodchip will keep its vibrant colour for up to two years.

Lasts 2 years

Product Info & Prices: Red Mulch


Choose The Right Mulch For Your Garden

Simply Soils are a bulk distributor for Richgro mulches. In this interview, Nick Lenzo from Simply Soils talks all things mulch with Rob Gileno. Rob is the Manager at Richgro Landscape and Commercial at Landgate. They discuss what goes into their mulch blends, which blend suits which circumstance, and the Australian Standards quality control.

Richgro History

Nick: I believe you’ve had a long association with Richgro?

Rob: We’ve been here for nearly 17 years. Richgro is actually a family company that was put together more than a hundred years ago. We were originally called Amazon Soils and they purchased the Amazon side of the business about 17 years ago. Now we actually come under the Richgro banner as Richgro Landscape & Commercial. We supply anything from bulk soils, mulches, composts to specialist mixes. We are located at Richgro, Jandakot. We supply bulk nurseries, production nurseries, and soil home delivery services like Simply Soils.

Most Popular Blends

Nick: What would you say your main blends are?

Rob: The main blends are basically your Landscape Mix, lawn mixes. On the mulch side of it, you’re probably looking at something a little bit more of a budget type blend that we sell quite a bit of, which is the Budget Black.  We then move on to something like Jungle Mulch, which is very black and very dense. People like that black look.

Everyone has their own preference for the look they want. If they want a native garden, they go with something like a bit of a Wood Chip or Enviro Mulch. 

Nick: With the mulch products specifically, would you say the main difference between them would all be aesthetic because functionally, they’re all good quality mulches, aren’t they?

Rob: Predominantly aesthetics, yes. When you get the bottom of the range products like Enviro Mulch or Budget Black, nutritional wise they’re very close. They are just basically a cheap type of product that customers can use.

Nick: Purely ground cover?

Rob: Purely ground cover, yes exactly. Then you start moving up to products like your Sandgroper Mulch, Jungle Mulch or Exotic Mulch, which have got more organic material blended in for nutritional value.

Nick: Okay, so it’s like a feed’n’mulch?

Rob: Exactly.

Nick: A one-pass product?

Rob: Exactly, yes.

Nick: So is Exotic the newest mulch?

Rob: Exotic is the newest mulch. It’s a fine mulch that has taken over the Karri & Peat because it is a similar texture. I think it’s a much better mulch as far as nutritional value. Whereas your Karri & Peat has been around for a long time, a fine mulch, the only problem with that is that it tends to bind together and not let the water through. The Exotic Mulch product is a little bit more open. Nutritionally wise, it’s also got a lot more nutrient level in it.

Nick: So, your Exotic will, once you’ve installed it, stay permeable?

Rob: Yes.

Nick: It will let the water down into the soil and then help reduce evaporation, rather than staying on the surface and letting the water runoff?

Rob: Exactly. As it degrades down or decomposes down, it adds beautiful nutritional value to the soil.

Nick: Is that because the Exotic Mulch contains some sort of conditioner in the blend?

Rob: Definitely. Yes.Nick: 

Thanks Rob, that’s a very useful thing to know when choosing a mulch for your garden.