The Dirt on Mulch in Florida: Part II

Editor's Note: this is the second part of Steve Woodmansee's post on mulch, the first part can be seen here or you scroll down.
Organic Mulches

Yard Clipping and Leaves (stuff from your yard)
For permanent plantings, it is ideal to use clippings and leaves from your own yard. This helps prevent the overfilling of landfills, leaves no carbon footprint, and also saves money. Any leaves raked should be incorporated into the landscape. Pruned branches may be further cut up, and then spread over the area desired, or kept in brush piles (adding to the wildlife component). Larger branches may be left in a specific area for a time being so that the leaves fall off the dead branch and may be gathered later. When tree services are used, plan on keeping the mulch created. Lawn clippings may be also used; be aware that weed seed may be a component of them. Another source of green manure is excess algae and plants from your pond or water feature, this is best reserved for fruit trees and vegetable gardens.

Local tree trimmer mulch (seen in this photo) is perhaps the best mulch of the bunch. Just like using stuff from your yard, recycling tree trimmer mulch reduces landfill waste, leaves a small carbon footprint, and can be cheap or even free. It generally comes by the truckload however, so space is needed to store it. Curing the mulch is essential before applying. Let the pile of mulch sit for at least one month. As it breaks down, the composting process creates heat which then sterilizes the weed seed that may be present. You will even see steam rise from the top of the pile. I always keep a pile in my yard to use as needed. In addition to commercial tree trimmers, loads of mulch may often be obtained from local power companies and government agencies, such as parks and recreation. There are often mulch transfer stations where it may be obtained for free in smaller quantities. A potential drawback is that the aesthetic quality of local mulch varies. However the nutrients are largely the same.

Cypress Mulch
Cypress Mulch should be avoided. Sixty percent of cypress mulch comes from deforested wetlands, and isn’t sustainably harvested. It is one of the cheapest mulches for this reason. For more details click here for this helpful brochure from the Suncoast Chapter.

Eucalyptus Mulch
Eucalyptus mulch comes from trees that are farmed for the sole purpose of mulch production. It is attractive and durable, but also more expensive. It can be found at most garden stores however. For smaller plantings, and situations when local mulch is not available, it is a better alternative to cypress mulch.

Melaleuca Mulch
Under the brand name, Florimulch, this mulch is ideal as it is produced from large stands of invasive Melaleuca quinquenervia from our natural areas. It isn’t farmed, and companies aid local governments by removing this invasive as a service with the intention of converting them to saleable mulch. One needn’t worry about melaleucas coming up in one’s yard as the mulch is heat sterilized, thereby killing any seeds that may occur. It has the other added benefit of being somewhat allelopathic, futher inhibiting weed growth. It can be a bit more expensive than other mulches. Another drawback is that it is difficult to obtain as few stores carry it. It is up to us to let our garden stores know that it is in demand.

Pine Straw
Pine straw is a popular alternative. It is gathered as a byproduct from pine plantations, and sold in bails. Byproducts are better by their nature, of course. Attractive, and consistent, it is well used in more formal landscapes. It is lower in nutrients, and does further acidify the surrounding soil, which may also inhibit weed germination.

Pine Bark Nuggets
Pine bark nuggets are also byproducts. They are larger, and break down more slowly than typical ground up mulches. They are a good choice for paths to be distinguished from surrounding mulched areas.

Pine Chips
Pine chips, also byproducts from pine harvesting, are often are derived from smaller branches not used in lumber products. They are lower in nutrients, but may be cheaper than some mulches.

Hay and Straw
Hay and straw may be incorporated as mulch or in your mulch regime. They make a good first layer, covered by more expensive mulches. They tend to be neat, thus good for higher traffic areas.

Inorganic Mulches
Gravel doesn’t add too many nutrients, however it does insulate and conserve soil moisture. It may also alter soil chemistry depending on its alkalinity. Gravel is optimal for high traffic areas, stylized planters, or areas adjacent to buildings. Gravel may come in many different forms, sizes, and rock types. Pea rock is a local product coming from limestone mined in Florida.

Recycled Tires
Recycled tires are converted into a mulch, and their use is somewhat controversial. Tire rubber is synthetic, and may contain harmful chemicals. It lasts longer than other types of mulch (it doesn’t break down very well), and is often used in playgrounds. Like gravel, it doesn’t add nutrients, but does insulate and conserves soil moisture.

Other resources:
Which Mulch is Best in Your Garden ?
Mulch Pros and Cons
Free Mulch

Steve Woodmansee
Pro Native Consulting


dreamhonda said…
Just wanted to pass along some information regarding your comment about pine straw acidifying the soil. I did some research regarding that subject. If you have a chance, please read my report here:
Rick Brown said…
Is there a concern of spreading Old World Climbing Fern contained in bales of pine straw or is that problem trivial?
Ginny Stibolt said…
I highly recommend the tree cutters' mulch. I've been using it for years in various types of projects. It is better (lasts longer) when it's harvested in the winter here in northern Florida, because there are fewer leaves in the mix.
From Kristina Serbesoff-King:

In north Florida there have been several incidences of pine straw mulch containing Japanese climbing fern. Here is a related article in Wildland Weeds Spring 2005 issue

Definitely something to watch out for.

thistleandthorn said…
Steve, I appreciate this 2 part info but there are a couple of issues I wish you would address. One is the amount of nitrogen used by hardwood mulches in the process of decomposing, and whether you feel the need to provide extra nitrogen when using fresh hardwood, so as not to 'rob' the plants. Another is this god-awful red mulch used everywhere in Florida. What is used to color that mulch (also black, brown dyed mulch, etc.) and what are the long-term effects of the dye on the soil? And, perhaps making the point that the benefit of mulch is improving the soil structure, so that a mulch which breaks down more quickly is actually preferable (to us gardeners, anyway). Thanks!
Hobo Botanist said…
thistleandthorn, I don't recomend using any petroleum based inorganic fertilizers (or pesticides). I also believe in allowing plants grow at their natural rate as best as possible. I have used chicken manure (from my backyard chickens) in addition to mulch on my fruit trees and gardens. I do agree that colored mulches aren't ideal as they provide little in the way of nutrients, and are primarily used as decoration with modest amounts of water conservation. And yes, mulch improves the soil, except in the cases of low nutrient coniferous communities (as discussed above). thanks for your observations, and I hope this helps
The conference has had all of us jumping but we wanted to thank all of you for the great comments! Mulch is certainly an interesting subject.

We agree with a previous commenter that red mulch usually tends to overpower instead of complement the plants in a landscape. Although the sellers have given assurance that the dye is not toxic, at the very least the use of dye means one more processing step, so who needs it.

There is no one-method-fits-all for the use of hardwood mulch. Added nitrogen for veggies may or may not be needed depending on your soil type and what you are growing. As far as adding more as fast as possible for the purpose of building up the soil, again, it depends. Most people would say that it is so much work, and expense that they would just as soon have the mulch stay in place as long as possible and do its job.
Unknown said…
Any studies done on using Spanish moss as a mulch?
Unknown said…
I have 3 camphor trees that constantly drop leaves. I know that this tree is an invasive species but bought the house with them full grown. Are these leaves similar to eucalyptus and can it also be tecckmended to use as mulch?
FNPS said…
In the event the original author does not address your question. Here is a link to some information that may be helpful:
Hobo Botanist said…
Hi Barbara,
It has been a couple of years, and I do not follow my old articles, but to answer your question. Spanish moss could be used, it certainly helps retain moisture, it may be somewhat lower in nutrients, but is still organic.

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