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Mulch samples

Mulch 101

It’s a great time to replenish mulch around trees, shrubs, & landscape beds. Here’s a quick lesson on the whys, whats and hows… of MULCH.


Q: Why use mulch?

A: A thick layer of mulch can help reduce weed issues, moderate soil temperature, and retain moisture around the root zone of your plants. As mulch breaks down, it can help improve the texture and fertility of your soil. It can also help to create visual contrast to the surrounding plant material and structures (homes, building, etc.)

Attractive bed of landscape plants surrounded by pinestraw mulch

A thick layer of pine needles can make an attractive mulch.

Mulch mimics the natural processes you find in healthy, mature forests. In a mature forest, there will often be a thick layer of leaves or needles blanketing the ground, creating a tidy forest floor without much weedy undergrowth. The leaves or needles slowly break down, creating rich soil.

Mature forest with thick blanket of needles preventing weeds.

Above: The ground underneath a mature stand of pine and cypress trees is blanketed in a thick layer of needles. The natural layer of mulch minimizes any weedy undergrowth.
(Photo taken in Jay B. Starkey Wilderness Park, Pasco County.)

Q: Which mulch is right for me?

A: When choosing mulch, you’ll probably want to consider factors like cost, durability, sustainability, and appearance. Below are brief descriptions of the most common types of mulch available to FL gardeners.

 Box with samples of various types of mulch


Pine bark is a byproduct of the forest industry. It comes in various sizes. It typically has a dark brown color. PROS: sustainable; long-lasting; decomposes very slowly. CONS: may float or wash away during heavy rains.

Pine straw typically comes from pine plantations which produce paper and wood products. Because they “knit together,” the pine needles are less likely to wash away than some other mulches. PROS: sustainable; won’t wash away. CONS: color options limited to natural pine needle color; availability is limited in some areas, therefore it can be more difficult to find than some other mulches; not very suitable for foot traffic.

Eucalyptus mulch typically comes from plantations in South and Central Florida, where the trees are grown specifically for this purpose. They grow quickly, so this mulch is considered renewable. PROS: available in various colors. CONS: low in nutrients.

Melaleuca mulch is made from the exotic invasive trees. The product is cured at a high temperature to kill the seeds so they won’t germinate in your garden. PROS: available in various colors; promotes removal of invasive exotics; doesn’t float; not attractive to termites. CONS: low in nutrients.

Mixed hardwood mulch is produced from scrap lumber, recycled pallets, or tree stems too small for use in paper or wood production. PROS: available in various colors. CONS: low in nutrients.

Utility mulch is sold or given away for free by many utility companies. This mulch comes from trimming trees and other plants that get in the way of power lines; but be aware that it can come with weed seeds. PROS: Typically free. CONS: Quality varies; may contain large chunks, seeds, etc.

Fallen leaves (including grass clippings) can sometimes be raked up for free in your landscape. This type of mulch is high in nutrients but decomposes quickly. PROS: free; may improve soil fertility better than some other mulches. CONS: may be less tidy looking for formal landscape settings; needs frequent replenishment.

Cypress mulch may be made from the waste wood generated in the manufacture of lumber for fencing, flooring, furniture, and other products, BUT… it may also come from whole trees cut from wetlands. Because its origins may be difficult to determine, the Florida-Friendly Landscaping Program does not recommend the use of cypress mulch at this time.

Gravel, pebbles, or shell can sometimes be useful (sparingly) in borders or pathways, but they won’t contribute to the soil’s nutrient content or water-holding capacity. If you use this type of mulch, make sure to first install a woven ground cloth to keep it from sinking into our sandy soils. This type of mulch lasts a long time, but it will need to be cleared of debris to look its best. PROS: Long-lasting. CONS: Very difficult to keep looking neat and weed-free; may increase soil temperature; no nutrient value. Note: Crushed shell can affect soil pH.



When replenishing mulch, DO NOT pile it in a heap directly against the base of your plants, trees, and shrubs. That can actually kill your plants (which probably isn’t your goal….)

Mulch piled in a heap around the base of a young tree.

Above: An excellent example of how NOT to pile mulch around a tree’s trunk! This is commonly referred to as “volcano mulching.”
(Image source:


So remember, give your plants a little “personal space” around the base…  and keep the root flare exposed.

Illustration of proper mulching, with space left around the plant.

Above: An illustration of the correct way to apply mulch around new plant material. The planting hole was dug at least 2x the width of the root ball. The entire back-filled area is covered with a thick layer of mulch, but the root ball is NOT covered by mulch. The root flare is exposed, and above the soil-line. Remember: “Plant ’em high, they won’t die. Plant ’em low, they won’t grow.”


Tip: Trying to estimate how much mulch you’ll need? There are a number of helpful mulch calculator tools available online. These can often help determine how many cubic yards or how many bags you’ll need.


A quick side-note about mulch & pollinators!

Native bee visiting a blanketflower

Several species of FL native bees are ground-nesting, which means they require patches of bare, open sandy ground. To attract and support these fascinating pollinators, try to pick a few areas of your landscape to remain mulch-free. These should be areas that are not subject to erosion, and where the nearby plants are more tolerant of dry soil. For more info about some of our native bees, check out:

A note on organic mulch vs. inorganic mulch:

Sometimes you will hear a recommendations about using a thick layer of “organic mulch.” If you’re mainly accustomed to thinking about the term “organic” in reference to food labels, this can be confusing.

The term “organic” means something entirely different in the context of food vs. mulch.

For food, “organic” refers to methods of growing plants without the use of certain synthetic chemical pesticides or fertilizers.

For mulch, “organic” simply refers to materials that were previously living things – in contrast to something “inorganic” like a rock, or synthetic fabric…

Organic mulches will typically decompose over time. Examples of organic mulch would include leaf litter, pine straw, wood chips, etc.

In contrast, “inorganic” mulches would NOT decompose over time. Examples of inorganic mulches include synthetic weed barriers, rocks, rubber playground mulch made from recycled tires, etc. These materials do not decompose, they do not improve soil texture, and they will not add any nutrients to the soil.

Hope that helped clear up any confusion. Happy mulching!


References & further reading:

UF Research – “Landscape Mulches: How quickly do they settle?” –

“The Facts About Termites and Mulch” –


About the Author: As one of the Florida Friendly Landscaping (FFL) Program Coordinators in Pasco County, Frank works with the residents, homebuilders, and businesses of Pasco to achieve attractive, resilient, low-maintenance yards and communities while reducing over-reliance on irrigation, fertilizer, and pesticides. (Click to learn the 9 Principles of Florida-Friendly Landscaping!) Through an innovative collaboration with Pasco County Utilities, Frank provides on-site assistance to individuals and communities identified as high water users. He can be reached at (813)929.2716.

Not in Pasco County? Not a problem! Click here to find your local UF/IFAS Extension office!

About UF/IFAS Extension: UF/IFAS Extension serves as a source of non-biased, research-based information for the residents, businesses, and communities of Florida, providing educational materials and programs for adults and youth. We proudly “provide solutions for your life.”

UF/IFAS Extension Is An Equal Opportunity Institution

by Frank Galdo

12 Comments on “Mulch 101

  1. Can someone tell me why my Persimmon tree is not bearing fruit? It barely grow has few leaves despite all the care i gave. Do you think the roots are affected by root pests ?
    Any advised will be appreciated.

    • Hi, thank you for checking out the blog, and for your question. There can be a number of factors that potentially could be affecting your persimmon tree. We’ll need a bit more background info to help narrow down the possibilities, so I’ll follow up by email.

  2. Where can I buy eculyptus mulch in nugget form? Anyone? I live in Delray Beach Florida

  3. I purchased bagged melaleuca mulch. What is the best way to store my extra bags?

    • Hi Pam, thanks for checking out the blog! I don’t know that anyone at UF has done any official research on best storage practices for bagged mulch. However, here are a couple of general tips and things to consider –

      1) Bags will likely be degraded by the UV in sunlight, so to avoid a bag blowout when you eventually try to move it, try to keep it covered, or someplace shaded.

      2) The longer it sits, the more it will break down. Moisture will speed up the decomposition of the mulch. The wetter it is, the faster it will break down. Eventually, it could end up somewhere between mulch and compost.

      3) Over time, you may see white mycelium* growing in the mulch, unless it is really, really dry. That’s perfectly normal & still safe for using around your plants. (*Think of mycelium as a bit like the “root system” for the beneficial fungi that help decompose leaf litter and dead wood – a bit of an oversimplified comparison, but that’s the basic idea…)

      4) Keeping it up off the ground (i.e put on pallet, etc.), might help reduce ants and other critters.

      Hope that helps!

  4. Thank you Frank.
    Our HOA mulches every year but the mulch is never turned and seems too thick in many areas. I’d like to share with the board of directors, your recommendations on turning mulch, frequency, time of year, pros vs cons, etc.
    I see you recommend 3 to 4 inches in thickness, how much is too much and why?
    Thank you very much.

    • Hi Steve – Thanks for checking out the blog! Regarding your questions about mulch depth and turning mulch, the answers will probably depend on a number of different factors (i.e. type of mulch, environmental conditions, aesthetic goals, etc.), so it’s difficult to provide a good “one-size-fits-all” recommendation… The 3-4″ recommendation comes from the fact that it’s often a good functional balance between preventing weeds while still allowing water to percolate through. Mulching at less than 3″ will tend to diminish the mulch’s weed-blocking capabilities, while using more than 4″ will often start to intercept too much rainfall, and can potentially even begin to affect gas exchange with the soil, etc… So it’s about striking that balance.

      (Also, mulch costs money, so if you’re working with a budget, and a 4″ layer is effective, why spend extra $ for minimal benefit, right?)

      Regarding raking, here are a couple of factors to take into consideration –

      In some situations, there’s no turning necessary – (particularly if leaves and pine needles are being used) – because the natural networks of soil microbes & decomposers do a great job of transforming these mulches into a rich layer of humus. So if using needles and/or leaves, you’d probably just want to spread more on top to replenish the mulch as it breaks down.

      In other situations, especially where wood or large-chunk bark mulches are used, there can sometimes be benefits to raking… BUT it’s ultimately going to depend on the site conditions, etc.

      The primary reasons to turn or rake the mulch would be:

      1) Some mulches are extremely slow to break down, so they may fade in color before they actually NEED to be replenished (from a functional standpoint). If your community’s mulch is primarily being re-applied because it’s lost its “pizazz,” raking can potentially help revitalize and refresh the appearance of the mulch between re-applications. (That saves $ and prevents the mulch from piling up too excessively.)

      2) Over time, certain mulches – especially wood-based mulches – can become very matted to the point where they begin repelling water. If the mulch is very matted, raking can help break up that “waterproof” surface layer, helping water penetrate again.

      3) If the mulch has spread from where it was originally applied, and is now encroaching on plants, walkways, etc. it may need to be rearranged back where it belongs.

      So long story short, consider the mulch’s function, looks, and costs, and let those factors determine the correct approach.

      I hope that helps. Feel free to follow up with me by phone or email if you’d like to dive into specifics for your community’s landscaping. or 727.514.5488

  5. We are removing a lot of the grass in our yard and replacing it with Florida friendly plants. Is there a mulch you would recommend. Our landscaper recommends Cyprus but with the ecological damage that we are causing from removing Cyprus trees I am concerned about this.

    • Hi Ken, thanks for checking out the blog!

      Due to the difficulty in tracing the origins of the cypress trees used for production of mulch, the Florida-Friendly Landscaping Program encourages alternatives such as melaleuca, eucalyptus, pine bark, pine straw, etc. They are effective mulches which offer better assurances of sustainability. Each has some pros and cons, as outlined in the post above. If you’re converting large areas, it can sometimes be beneficial to solarize the ground prior to planting, or use some other method to address the dormant seed bank. Otherwise, weeds can definitely become problematic, even with a decent layer of mulch. Dr. Chris Marble did a great webinar a few months back discussing a variety of good weed control strategies. The link for the recording is:

      If you’d like some advice for any specific sites you’re working with, please feel free to get in touch with us. We’re happy to follow up by phone or email. Hope that helps!

  6. If the mulched area is sloped (slightly) towards the street, can a border keep it where I want it? Or will it become another high-maintenance project?

    • Hi Kay, thanks for checking out the blog!

      A border can potentially be helpful in some situations. A good solution for a slight slope can sometimes include using a border in combination with a mulch like pine straw, which tends to “knit” together. Another trick that can help is to create a slight “dip” behind the border by removing a bit of the soil back there. It doesn’t necessarily need to be a major trench. Just a slightly lower area…

      (Side-note- Pine straw has recently been difficult to source in some areas. Hopefully, dry fall weather will be more favorable for baling, and the supplies will rebound.)

      It’s difficult to make a blanket statement though, because each situation can be different… Often, your ability to keep the mulch in place using the various solutions mentioned above will depend on a combination of both the slope, and also the volume of water that’s pooling or flowing through the area. For example, if a downspout causes a LOT of water to flow through at a high rate, that can definitely increase the concerns for washout, etc.

      One thing especially important to keep in mind is that if the area has standing water during any of our wettest summer rainy periods, certain types of mulch (i.e. pine bark nuggets) might go floating down the road…

      Feel free to send me some photos by email if you’d like some additional brainstorming of solutions – or if you’d like to show some before/after success stories. Those are always great too!

      Hope that helps. Happy gardening!