Everything You Need to Know About Cedar Mulch

Sharing is caring!

If you've been into gardening for a while, you may be aware of the love-hate relationship about cedar mulch among gardeners. And if you're like most people, you may have chosen a side.

Those who dislike it argue that cedar mulches will kill other plants—especially germinating seeds or young seedlings as a result of what many believe are the allelopathic compounds allegedly found in the mulch.

However, there's a group that swears by this type of mulch.

They are convinced that aside from aesthetics and the primary role similar to any other mulch, cedar mulch does repel bugs.

And there are those who don't have a strong opinion about this debate. Those who are likely to consider the pros and cons before deciding on whether to use the mulch or not.

So, which side are you on?

Regardless of your inclination, there's something for everyone in today's post. The truth of the matter is; while there are valid reasons for your beliefs, some are rather myths than truths.

I've explored this topic extensively and here's everything you need to know about cedar mulch.

Let's begin:

What's cedar mulch?

Cedar mulch is a type of organic material composed of cedar bark, sawdust, and other cedar wood particles. The mulch is available in natural or red-colored varieties and has a strong scent due to the presence of volatile oils.

These oils are released when the mulch is exposed to heat and regular rainfall.

The mulch is essentially a bi-product of the Eastern Cedar, Juniperus virginiana, which is considered an invasive species because of its encroachment onto U.S. pastures and rangeland.

It is also a host for cedar-apple rust and must be removed near apple orchards to prevent the disease.

This is probably the reason why the resulting mulch gets a bad reputation by extension.

Is Cedar mulch toxic?

As earlier highlighted, there's a group of gardeners who believe that cedar mulches are toxic and therefore likely to kill other plants.

On the contrary, that is more of a myth than a fact since there's no scientific evidence to support these claims.

While it's scientifically true that some woody plants contain allelopathic chemicals, for example, Black walnut (Juglans nigra), it has not been shown to have negative effects on other plants when wood chips are used as a mulch.

However, there's a general consensus that volatile oils from cedar can repel or kill other types of insects including mosquitoes, houseflies, little ants, and ticks.

Now, two questions:

Is cedar mulch toxic to other plants? the answer is no.

Is cedar mulch toxic to insect pests? Probably, Yes - and will discuss more on this later.

Cedar mulch vs Cypress mulch

The two types of mulches have quite similar properties—including water retention and weed suppression abilities.

The main difference between them is the scent. Cedar mulch has a stronger aroma due to its higher levels of volatile oils.

Cedar mulch vs hardwood mulch

Hardwood mulches are mostly composed of deciduous trees and have lower acidic levels than cedar mulches.

They also break down faster, offering more nutrients to the soil and plants. Hardwood mulch also helps keep soil temperatures cooler, making it great for tropical climates.

Cedar mulch vs pine mulch

Pine mulches are often made from needles, cones, and bark of softwoods such as cypress and pine trees. They retain moisture more efficiently than cedar mulches and are not as prone to acidity.

Additionally, they tend to be less expensive than cedar mulch.

Does cedar mulch repel bugs?

The short answer is yes, cedar mulch does help repel bugs due to the presence of volatile oils in its composition.

However, you should bear in mind that the effectiveness of this repellency may vary depending on the type of bug.

According to this report, the mulch is more effective on ants which are often associated with attracting aphids and whiteflies.

Pros and Cons of cedar mulch

Cedar mulch has several advantages, such as weed suppression and water retention capabilities. It is also aesthetically pleasing and helps to repel bugs.

On the downside, it can be more expensive than other types of mulch and is not suitable for all climates.

Cedar Mulch application

When using cedar mulch, it is important to ensure that you apply it correctly.

For best results, spread the mulch in a 3-4 inch layer over soil or around plants, taking care not to cover the stems or leaves of plants. Water the mulch shortly after application to ensure that it is properly settled into the soil.


Cedar mulch can provide many benefits when used correctly. Its long-lasting properties, repel bugs capabilities, and aesthetic appeal make it a popular choice for landscapers and gardeners alike.

While there are some drawbacks, such as the potential for higher costs and unsuitable climates, its advantages make it a viable option for many gardens.

We hope that this article has given you enough information to decide whether cedar mulch is right for your project. With proper application and maintenance, you can enjoy its benefits for years to come.