Cedar Mulch

You can’t miss the regal presence of a cedar tree in a garden, but you may miss its humbler presence, low on the ground, surrounding shrubs and flowers, not as a towering conifer but as mulch.

Yes, because cedar mulch is as common in flower beds and pots as it is particular. It is, in fact, a bit “special.”

Cedar mulch is made from clippings and shavings of the bark of cedar trees. It is used to cover the ground, but it cannot be used at all times. In fact, its particular properties, including its insect-repellent smell and effects on the soil, make it excellent for some purposes but counter indicated for others. 

So, cedar mulch is not “any mulch,” and you cannot use it as such. This is why we need to talk about its properties, its effects, its uses, and also, of course, its drawbacks… Ready to find out?

What is Cedar Mulch?

What is Cedar Mulch

Cedar mulch is made from clippings and shavings of the bark of cedar trees, any of the conifers of the genus Cedrus, majestic trees originally from the Himalayas and Mediterranean Basin.

It is a byproduct of the wood industry, as these trees are sought after for their wood. They grow fast, and they are fairly straight, which makes the wood and the mulch obtained from them renewable.

The mulch itself can be natural or dyed for aesthetic purposes; while the natural color is reddish-brown, it is often died black, yellow, dark brown, or red, which adds to the decorative value of flower beds and gardens when you use it.

Why Do Gardeners Use Mulch?

Gardeners Use Mulch

Let’s look at the big picture: why do you see mulch in flower beds, vegetable gardens, and in houseplant pots? You may have seen that mulching is becoming more and more widespread in decorative and vegetable gardens alike.

The core idea is very simple: Nature covers the soil whenever she can. Look around you; when the soil is bare, small plants (grasses, musk, even algae) come first, then bigger ones, and so forth.

When the soil is not covered, it deteriorates. Rainfall, wind, dry conditions and even temperature changes impoverish the soil, which loses nutrients and organic matter, and this is the beginning of the process of desertification.

To give you a shocking fact, when you dig or till the land, it loses 10% of its carbon in 24 hours…

So, part of the organic revolution is the understanding that if you want fertile a soil, you need covered soil.

Reasons Why Mulching is Good for Your Garden

But let’s look at why mulching is good in detail:

  • Mulch keeps the moisture of the soil. This is why if you go to forward-looking organic gardens, even vegetable farms, you will find plants growing in beds of straw (mostly) or other mulch, especially in hot and dry countries.
  • Mulch keeps the soil temperature steady; as it forms a barrier between the earth and the air, it keeps the soil’s temperature higher. In the soil, there are microorganism that work all the time, and they produce heat. If the heat does not disperse into the atmosphere, your plants’ roots will be kept warmer and safer. Winter mulching is in fact very common with plants that do not tolerate low temperatures.
  • Mulch is a way of controlling weed; grasses find it hard to grow in the dark, and this blanket on top of the ground we call mulch is a cheap and permanent way of having fewer unwanted green guests in your garden.
  • Mulch preserves the nutrients in the soil; that very top layer of soil where microorganisms decompose organic matter needs protection from wind and dry weather and direct sunlight.
  • Mulch can act as a pest control method; not all mulch is equal at this, and cedar mulch is actually the best. We will see why.
  • Mulch is also used for decorative purposes; this, I am sure you have seen with your own eyes.

Inert and and Non-Inert Mulch

Mulch is not just cedar (or other trees) bark and shavings: anything that forms a layer of protection on the ground could count as mulch, even stones, gravel, cardboard, a blanket, or an old carpet.

But some materials are inert, which means that they never interact with the soil. Others, conversely, will have a low level of interaction.

Stones are inert, for example, but the bark is only partly inert. Why?

Especially if fresh, when it starts to decompose, it absorbs nitrogen from the soil… Later on, however, it may actually give nutrients to the soil as the composition process progresses.

It is also important to check if the mulch you use changes the soil pH. Pine needles are notoriously believed to turn the soil acidic, but this is only true if they are green, while wood bark and clippings may have this effect – including cedar mulch!

However, this is only true if your cedar mulch is not aged. If it is at least one year old, the effect on the acidity of your soil is negligible.

Keep this in mind when you buy it or, if this is the case, make your own cedar mulch.

Pros and Cons of Cedar Mulch

Don’t underestimate the advantages and disadvantages of each type of mulch! It can make a huge difference to your garden because the mulch will stay on the soil for a long time.

Actually, especially with cedar mulch, its qualities and drawbacks are quite marked, and this makes it suitable for some uses, but by no means all. So, let’s see them in detail.

Advantages of Using Cedar Mulch

Advantages of Cedar Mulch

Cedar mulch has some very particular qualities that can be an advantage for your garden. Here they are:

  • Cedar mulch lasts long: especially compared with other organic mulches (like straw, for example, but also other bark mulches, like pine mulch), cedar mulch does not deteriorate fast. This means that once you have put it on the soil, it will last even for years.
  • Cedar mulch is an insect repellant; this is possibly the reason why it is a favorite with many gardeners. Insects hate the smell of cedar mulch and they keep at a distance. So, as well as mulching your ground, it also keeps pests at bay.
  • Cedar mulch offers good ground cover; this, of course, is a key quality in any type of mulch.
  • Cedar mulch has a nice natural color; of course, if you are using it in a decorative garden, its warm red-brownish hue is added value.

Disadvantages of Cedar Mulch

But cedar mulch is by no means perfect; in fact, its downsides are enough to limit how you can use it in your garden:

  • Cedar mulch also repels pollinators and beneficial insects; this is the flip side of its pest control qualities: it will also affect the ecosystem negatively, and, especially if you want your plants to fruit or produce seeds, cedar mulch is not a good choice.
  • Cedar mulch is expensive; it costs more than average mulch, and this can be off putting.
  • Cedar mulch can release acetic acid, which can hurt your plants; this is not a must, it only occurs if the mulch has not received enough oxygen when it is stored after production.
  • Cedar mulch decomposes slowly; hold on, wasn’t this an advantage? Yes, but it is also a disadvantage as in the advanced stages of decomposition, it seeps nutrients into the soil, improving it, and cedar mulch will have a negligible effect in improving soil nutritiousness, unlike other mulches.
  • Cedar mulch loses color fast; this means that the decorative effect will soon diminish.
  • Cedar mulch has a strong smell, which some people find unpleasant.

Natural or Died Cedar Mulch?

Natural or Died Cedar Mulch

We said that you can get cedar mulch in its natural color or dyed. While red, yellow, brown or black mulch can look great in your garden, it does have a major disadvantage: the dye uses chemicals that will end up in the ground and ultimately even inside your plants.

This is bad for the environment, of course, but also for your plants and, if you intend to harvest them to eat, for yourself and your family.

If you have an interest in healthy living and the environment, dyed mulch is not an option, unless you are ready to fork out a small fortune for cedar mulch dyed with fully natural pigments…

Uses of Cedar Mulch

Uses of Cedar Mulch

Now, what can you use cedar mulch for? We have already seen how mulch has different “functions”, and cedar mulch is good for some of them:

  • Cedar mulch is good to repel pests.
  • Cedar mulch is good to preserve moisture in the ground.
  • Cedar mulch is good to control weeds.
  • Cedar mulch has high decorative value.

When to Use and Not to Use Cedar Mulch?

But how and where is cedar mulch used exactly? Here the story gets a bit more complicated…

  • Cedar mulch is used for paths and dog walks; this is arguably its best use. Because you do not need the soil to regenerate and because the mulch does not risk affecting your plants, this is a very safe use of cedar mulch.
  • Cedar mulch is also used to cover soil around plants and in flower beds. This is very common, but there is controversy about using it in flower beds. The reason is that some people believe that cedar mulch produces allelopathic substances, chemicals that plant roots do not like. But is it true?

Let’s investigate the second point; the fact that cedar mulch produces chemicals that affect the growth of your plant is discredited by scholarly studies, but there remain some questions…

  • Is this true for all types of cedar mulch? Did the study only look at good quality cedar mulch? We know that if it is not, it does produce acetic acid…
  • The study only concludes that it is “unlikely” that cedar mulch will affect the germination and growth of plants. It is not as conclusive as to give full confidence.

So, how can we go about this problem? With caution of course:

  • Cedar mulch can be used with well established plants; there is a degree of safety on this that, at this moment in time, can be trusted.
  • It is safer to avoid cedar mulch with seedlings, small plants and newly germinated plants.

Finally, A Very Important Point

Do not use cedar mulch if you want to invite pollinators and regenerate the ecosystem, especially in flower beds, but not just. Even a path can become a barrier to the natural corridors beneficial insects use to move from plant to plant.

As you can see, the actual uses of cedar mulch are restricted. With the wide range of mulches available, choose carefully according to your needs, your plans, your land and, naturally, your planting.

How to Use Cedar Mulch in the Garden?

Mulching is Good for Your Garden

But how do you go about actually mulching your garden with cedar mulch? You cannot just randomly scatter cedar mulch on the ground… You will need, in fact, to follow some key guidelines, and here they are:

  • First, calculate the area of ground you want to cover with mulch.
  • Next, calculate how much mulch you will need. To give you a rough idea, you will need about 2.5 cubic feet of cedar mulch for every 10 square feet of soil you want to cover. If you want your mulch layer to be thicker, you will need more. There are online calculators you can use.
  • Then, clear the soil from weed and grass. This should not be done long before you mulch the soil, or it will lose nutrients to the elements. Try to do it on the same day as you lay down the mulch or, at most, the day before.
  • After this, wet the soil if it is dry. In any case, make sure you put the mulch on the soil when it is moist.
  • Having done this, lay down 3 generous inches of mulch. About 3 inches is a good layer, you can go up to 4, but do not build big piles of mulch. Those are unnecessary and they will tend to slide down and touch the plants, which should never happen.
  • Importantly, make absolutely sure that the mulch is at a safe distance from trunks and stems. This is paramount, because if it touches the stem, the water in and on the mulch will come into contact with the base of your plant and this will cause stem and trunk rot. So, leave a few inches from each plant and the mulch.

That’s about it for a flower bed or group of plants.

How Can You Use Cedar Mulch around a Tree?

Cedar Mulch around a Tree

In case you want to mulch around the base of a tree, maybe a fruit tree, you will need follow these steps:

  • First, draw a vertical line from the last leaves on the tree branches to the ground. This is called a drop line. It shows where the roots of your plants have reached underground.
  • Repeat this for a few points around the tree.
  • Draw a circle around the tree that’s slightly larger than the drop line shows. This is the area you will have to mulch.
  • Now, calculate the area and how much mulch you will need.
  • Next, if you live in a dry area and you are mulching to preserve humidity, dig a swell around the trunk as wide as the circle you have drawn.
  • On the other hand, if we’re you live is wet, you can just remove weeds and grass etc.
  • Then, lay down the mulch, making sure it covers all the bare soil in the circle. Again, 3 inches will suffice.
  • Finally and most importantly, make sure there are a w inches from the trunk to the mulch, all around. Even string trees can develop trunk rot if their base is in touch with mulch.

Having mulched an area (a swell) larger than the canopy of the tree means that all the rainwater that falls from the leaves of the tree will go back to its roots.

Can You Use Cedar Mulch in Vegetable Gardens?

Cedar Mulch in Vegetable Gardens

Cedar mulch is far more common in decorative gardens, even in public parks than vegetable gardens.

However, you can use cedar mulch in a vegetable garden if you want. However, there are some serious disadvantages and issues with it.

  • Cedar mulch is expensive; this means that it may not be profitable for a vegetable garden. Maybe if you have a small garden in mind, however, you may want to use it.
  • Cedar mulch deters pollinators; this makes it unsuitable for fruiting vegetables.
  • Cedar mulch lasts a long time, most vegetable beds last months, if not weeks. This means that you will need to rearrange the mulch every time you change crop, which may well mean that you need to remove all the mulch than lay it down again.

In case you do use cedar mulch for your vegetable garden though, still make sure it does not touch the stems of your plants.

This is a bit more tricky with many small plants in rows than it is to frame a flower bed or for a large tree…

Most gardeners prefer cheaper, lighter and more easily managed types of mulch for vegetable gardens, like straw, dry leaves or even cardboard…

Cedar Mulch, between Myth and Reality

Cedar mulch is a very famous and even popular type of mulch. It looks good; it lasts for a very none time and it also deters pests from your flowers, plants and crops. However, it may not be the best choice for all purposes…

Because it is has very specific characteristics, it is unsuitable for many jobs, including if you wish to invite butterflies and bees into your garden or land or if your aim is to regenerative the soil.

On the other hand, the long held belief that cedar mulch damages your plants does not seem to be fully true, so you can breathe more easily now on this.

On the whole, the best use of cedar mulch is to cover paths and for large flower beds or trees; it is durable, it is pleasant to look at and, given its price, you may want to keep it for the most decorative elements of your garden.

Amber Noyes

Written By

Amber Noyes

Amber Noyes was born and raised in a suburban California town, San Mateo. She holds a master’s degree in horticulture from the University of California as well as a BS in Biology from the University of San Francisco. With experience working on an organic farm, water conservation research, farmers’ markets, and plant nursery, she understands what makes plants thrive and how we can better understand the connection between microclimate and plant health. When she’s not on the land, Amber loves informing people of new ideas/things related to gardening, especially organic gardening, houseplants, and growing plants in a small space.

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  1. Avatar photo Myrna Nordhougen says:

    I am having a difficult time deciding whether to use beauty bark..compost or pea gravel in my flower beds. I don’t want to keep redoing it every..and want it to.look nice.

    1. In perennial flowerbeds, cedar and other wood and bark chip mulches conserve soil moisture and insulate plant roots against temperature fluctuations. In addition to making flowerbeds look attractive and tidy, cedar mulch also improves soil texture and suppresses weeds. on other hand Pea gravel absorbs the sun’s heat and retains it in the soil longer than other mulches, it helps the soil retain moisture and prevents soil erosion that can expose roots.

      I hope this could help you to choose.

  2. Avatar photo Mary Shortell says:

    I’m kind of confused because I read that you shouldn’t put the mulch around your plants but In some of the pictures it’s touching the stem.Is white cedar chips OK for tomatoes,green peppers in your flowerbeds? Is it necessary to cover the whole flower bed or just the area by your plant with the mulch. Or does covering the whole flower bed keep the moisture in better how often do you have to water then,how do you know to water?
    Thank you,Mary

  3. Avatar photo diana marr, allan marr says:

    We have a 25 foot row of cedar trees that started out being a hedge, but now they are trees about 40 feet tall with no leaves on the lower 20 feet, They are unsightly and now no longer give any privacy and are a possible fire hazard. We intend to cut down the row. If both the branches and trunks are chipped, does it make a good mulch that can be used on walkways? What about in flower or shrubbery beds? If walked on, is there sticky sap that can be tracked indoors on shoes? Our property has a number of large fir trees with rhodos and a natural forested look. We would like to put the chips to some good use. Thanks. D

    1. If you are anywhere close to Dallas, TX. I would love to have the trunks of the cedar trees. They make beautiful Furniture. Dennis 9/7/2/9/6/5/5/2/7/4. Thanks.

  4. Avatar photo Judy Skiff says:

    Can cedar mulch be used in a rose garden??? please reply. Thanks you. judy skiff@aol.com

    1. Yes you can. Actually I have found that shredded cedar mulch stays put okay for me in the very windy times and can be fluffed up and around a bit during the season to keep it looking nice.

  5. We plant native specifically for the birds, pollinators etc. I thought of using Cedar Mulch for a dog path but don’t want to hurt the ecosystem. Is there another mulch or groundcover you recommend?

  6. I have put black mulch in my flower garden for the appearance but have noticed several of my knock out rose bushes seem to be burning up. New flowers are not sprouting as usual. Is black mulch the reason?

    1. Dark colored mulch can hold too much heat in and reflect it back at the rose bushes, so you need to replace black mulch under your roses, and mulch any bare ground around them, with shredded cedar mulch or light-colored mulch.

  7. This was a very informative article. Neither my husband or I were aware that cedar mulch was an insect deterrent, although when I think about the use of the wood in closets and chests, that’s just what it does. I’m horrified. We just laid 3 inches of cedar mulch throughout our flower beds which I’ve been switching over to native plants to better serve the butterflies and bees. Will the effectiveness of the cedar mulch as an insect deterrent be reduced each year so I have some hope of attracting them again in the future?

  8. I would not put pea gravel anywhere except a walkway or rock garden. If you put it in your plant beds, you won’t be able to work the soil as needed, or you would have to keep adding more and more, and then the soil would become too rocky to be ideal for plants. It is pretty much intended to keep plants away, rather than encouraging them to grow.