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.)
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.
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.
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….)
So remember, give your plants a little “personal space” around the base… and keep the root flare exposed.
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!
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: http://blogs.ifas.ufl.edu/seminoleco/2017/11/29/native-bees/
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?” – https://edis.ifas.ufl.edu/publication/FR052
“The Facts About Termites and Mulch” – http://edis.ifas.ufl.edu/in651
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