by Sheila Dunning | May 17, 2019
Natural bark mulch
There have been a lot of questions about the use of colored mulches in the landscapes. Many individuals are concerned about the possibility of negative environmental impact from the dyes used on wood chips and pine straw. According to the Center for Agriculture, Food and the Environment (https://ag.umass.edu) the primary concern with colored landscape mulches is not the dyes used for coloring. Rather, it is about the sources of wood chips and the possibility of contamination with toxic substances.
The dyes used in coloring wood mulch are primarily of two types: carbon-based dyes and iron oxide based dyes. Iron oxide, the most commonly used dye, is simply a compound of iron and oxygen. As the compound oxidizes, iron is released to the soil but is not considered to be toxic. Dyes that are not absorbed by or adsorbed to the wood would come off with contact, especially if the mulch is wet. There are also some carbon-based dyes used on mulch. These carbon-based colorants are similar to those used in ink and cosmetics. Other dyes for mulch are vegetable-based and therefore organic. At this time, there is no evidence that the dyes used to color wood chip mulch are toxic.
Most of the wood used for making colored mulch comes from recycled wood, i.e. wood scraps, wood pallets, and wood reclaimed from construction and demolition (C&D) waste. Besides the benefits of recycling waste wood materials, the reason why these wood materials are used for colored mulches is that they are very dry and readily absorb or adsorb coloring agents.
Unfortunately, some of the recycled waste wood used for making landscape mulch products is contaminated with various chemicals, such as creosote and CCA (chromated copper arsenate). CCA is the chemical that was used in the manufacturing of pressure-treated wood.
Even though arsenic-based wood preservatives were banned in 2003, there are still plenty of CCA preserved wood being re-purposed. Sometimes wood pallets that have been used in the transport of chemical agents can become contaminated by spills of these chemicals. CCA and other toxic chemicals have been found to be contaminating soil where colored mulch made from these wood products have been applied. CCA treated wood can kill beneficial soil bacteria, beneficial insects, earthworms and young plants. It can also be harmful to people spreading this mulch and animals who dig in it.
Additionally, dyed mulches break down much slower than natural mulches. The greatest advantage to using them is to reduce the expense and time required to replenish the mulch. When wood breaks down, it requires nitrogen to do so. Colored mulch can actually rob the plants of the nitrogen they need to survive. Natural mulches retain moisture and add organic material back to the soil enabling the plants to better utilize nitrogen. Avoiding the use of colored mulches reduces the risk of contamination better than any other practices. Colored pine straw may be an alternative.
It should not be assumed that all colored mulches are contaminated. However, anyone planning to use colored mulch should become familiar with the supplier and the source of the wood used in making it. If C&D waste wood is used, it should be a red flag that there is a possibility of CCA contaminated mulch.
Certified Mulch Label
If you wish to improve the chances that the dyed mulch that you are buying is safe for humans to handle look for the MSC Certification Logo on the packaging. MSC stands for Mulch and Soil Council, whose responsibility is to certify that a mulch or soil product is free of CCA-treated wood. According to MSC’s Product Certification program, “Certified mulches and soils can be found at major retailers and garden centers across the country.” If you have concerns after contacting the supplier about the source of the wood used, contact a private environmental testing lab in your area.
While reading packaging, check the source of the product. If the supplier is a land management company rather than a processing mill it may be that mature trees are being removed and shredded. These mulches are sold as “long-lasting”, “no-float” products. They have the appearance of pine straw, but are actually finely shredded cypress from the heart of trees. These are coming from properties where the bald and white cypress trees are harvested for mulch. You can tell that it isn’t pine straw because the mulch pieces lack pine needle structures such as the fascicles and a revolute shape. While the use of these products is not contaminating, it is still depleting the environment. Mulches that are natural by-products are the most Eco-friendly.
by Julie McConnell | Jan 3, 2019
Storm debris turned into holiday cheer in Bayou George. Photo: J_McConnell, UF/IFAS
By the time this article publishes, we will be more than 70 days since Hurricane Michael toppled or damaged an incredible number of trees in the Panhandle. Enormous piles of once stately shade trees line the streets in neighborhoods and business districts in. The cleanup efforts have been phenomenal, over 4 million cubic yards of storm debris picked up in Bay County to date, but there is still a long way to go in the recovery process.
So, as gardeners, how can you help our community get back on track amidst your own struggles to recover? A few Florida Friendly Landscaping™ Principles come to mind.
- #1 Right Plant, Right Place – as you rebuild your landscapes, make sure to choose the appropriate plant for the location. Consider mature size and give those plants space to thrive!
- #4 Mulch – do you have bare ground that will eventually become landscape beds or turf but no resources or time to replant yet? Consider mulching the area to keep soil from eroding and to help improve soil though decomposition of natural products. Hint – see Recycling for free sources!
- Mulch tips https://sfyl.ifas.ufl.edu/media/MulchBrochure.pdf
- keep mulch 12 inches from tree trunks
- recommended depth in beds or under dripline of tree canopy (excluding within 12” of trunk) is 2-3 inches
- leave an 18-24 inch buffer around building foundations mulch free to reduce conducive termite conditions
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Dress up stumps with plants and whimsical designs. Photo: D_VanderMeer, UF/IFAS Master Gardener
#7 Recycle – driving around town I have seen some really creative uses for stumps, trunks, and branches that homeowners have constructed and messages of hope that bring a smile to my face. Another method of recycling is to use the chipped vegetative debris as mulch, either available as “utility mulch” by cities and counties or you may have some in your own yard right now.
- Utility mulch does come with some words of caution because there is an increased risk of introducing weeds to your landscape with untreated storm debris. However, if you need mulch for pathways or planting beds you will be helping your community’s cleanup effort by reducing waste accumulation. Just watch for “volunteer” plants and manage as needed.
In Bay County, there are 4 locations where you can load and haul off your own utility mulch from storm debris
- Under the Oaks Park – 5843 E. U.S. 98, Panama City, FL 32404
- G. Harder’s Park – 8110 John Pitts Rd., Panama City, FL 32401
- Chapman Park – 2526 Rollins Ave., Bayou George, FL 32404
- Laird Park – 6310 Laird Park Rd., Panama City, FL 3240
For sources in your county, check with your Solid Waste Department for utility mulch availability.
by Molly Jameson | Sep 25, 2018
The plasmodium of Fuligo septica slime mold consuming bacteria and fungi inside the office worm bin. Photo by Molly Jameson.
Just when we thought we had our Leon County Extension vermicompost bins all figured out for recycling office food waste with the aid of worms…aliens invaded. I instinctively started looking all over for my “Ghostbusters” proton gun and backpack – but when they didn’t turn up, I decided to retreat and do a little research.
Fuligo septica moves as a mass of protoplasm about a millimeter an hour. Photo by Molly Jameson.
A mesmerizing bright yellow substance had taken over the entire top of the office worm bin, and when the lid was lifted, the yellow ooze was streaming down the inside of the lid and into the bin. Long, squiggly zig zags seemed to be engulfing nearly all the contents within the worm bin.
Unlike Ray Stantz’s reaction when he first meets Slimer devouring the room-service leftovers in the hotel hallway in the original “Ghostbusters,” we were all a little taken aback by our surprise intruder.
“Oh my! Will it kill our worms? Is it toxic? Where did it come from?”
Turns out our slimy yellow visitor was Fuligo septica; a species otherwise known as – and here’s hoping you’re not eating – dog vomit slime mold. A fitting name, indeed. To our amazement, Fuligo septica is not actually a mold (aka: fungus). Nor is it a plant, animal, or bacteria. It is actually a plastid, in the kingdom Protista and class Myxogastria, whose wind- or insect-spread spores converge and divide into a singular giant cell containing millions of nuclei, known as a plasmodium. These individuals come together to form a larger plasmodium and move as a mass of protoplasm, about a millimeter per hour, to feed on microorganisms living in decaying plant material.
I know what you’re thinking…this smattering of scientific terms has you right back in high school science class, and you’re feeling a bit woozy. But really – who needs science fiction movies like “Ghostbusters” when we have scientifically-explained neon slime molds all around us?
After a few days, Fuligo septica transforms into a pillow-like fruiting body in preparation for spore dispersal. Photo by Molly Jameson.
Besides the potential of Fuligo septica spores to be an allergen to those who are susceptible, this surprisingly common slime mold is not toxic to people, plants, or animals. It can be found on rotting bark and forest floors in nature – or on wood mulch in urban areas – normally when conditions are moist. The microorganisms the slime mold consumes are mainly bacteria and fungi, which are also very much present in the decaying food scraps and coffee grounds within a worm bin. And although Fuligo septica is harmless to people, it needs to watch out for us, as it is actually edible! Appropriately, another name for dog vomit slime mold is scrambled egg slime, as indigenous people in some areas of Mexico have collected the mold and scrambled it like eggs. Breakfast anyone?
Although real-life slime molds give Slimer a run for his money, the plasmodium blob of Fuligo septica will not stay its striking yellow amorphous shape for long. After a few days, it transforms into a pillow-like aethalium – a spore-bearing fruiting body like that of a mushroom – then degrades, darkens to a pinkish tan color, and finally releases its spores to start anew when conditions are right.
As the slime mold degrades, it darkens to a pinkish tan color, and releases its spores into the air. Photo by Molly Jameson.
Slime molds have stood the test of time, as analyses of their DNA has revealed they’ve been on Earth approximately a billion years! For reference, that’s hundreds of millions of years before plants or animals. And it’s a good thing Fuligo septica is here, because some of its characteristics has shown a lot of potential to be helpful, including as antibiotics, an ability to fight cancer cells, as antimicrobials, and environmental site remediation due to its ability to hyper-accumulate toxic heavy metals, such as zinc, and convert them to inactive forms. Scientists have discovered it’s the same yellow pigment that gives Fuligo septica its striking color that also forms a chelate with the heavy metals.
So, if you’re walking through a forest, down a path of mulch, or tending to your worm bin and come across this eye-catching, bright-yellow blobby creature, let this plasmodium do its thing. Probably better to scramble some actual eggs, lest your guests be squeamish.
by Matt Lollar | Apr 23, 2018
Recently, an Extension Agent in the Florida Panhandle received a picture of some mushrooms popping up in a client’s garden. These particular mushrooms were in a spot where leftover mushroom compost had been dumped. The compost was previously used to grow oyster mushrooms and the client was hopeful that she had more oyster mushrooms growing in her yard. Unfortunately, the lab results came back stating the mushrooms in question were Armillaria spp.
Armillaria spp. in the garden. Photo Credit: University of Florida/IFAS Extension.
Armillaria spp. cause root rot of trees and shrubs throughout the world. The fungus infects the roots and bases of trees, causing them to rot and eventually die. Some species of Armillaria are primary pathogens that attack and kill plants, but most are opportunistic pathogens that are attracted to unhealthy or stressed plants. Fruiting structures of the fungi can be recognized by the clusters of yellow to brown-colored mushrooms that emerge during wet conditions. However, the mushroom caps sometimes never form and the plant material needs to be inspected more thoroughly to find the disease culprit. Infected plants may have wilted branches, branch dieback, and stunted growth and should be removed and replaced with resistant species.
White mycelial fan under the bark of a root infected with Armillaria tabescens. Photo Credit: Ed Barnard
Management – The best method for controlling Armillaria root rot is with proper plant installation and maintenance. Planting plant material at the proper depth will allow the roots to breathe and reduce the opportunity for the roots to rot. Pruning tools should be sanitized between plant material. Proper irrigation and fertilization will also reduce the risk of plant disease and root rot. Lastly, you can choose to plant a diverse landscape with resistant species.
For more information on Armillaria root rot and a comprehensive list of resistant species, please view the EDIS publication: Armillaria Root Rot
by Julie McConnell | Mar 13, 2018
Shore juniper forms a thick groundcover and tolerates hot, dry sites. Photo: J_McConnell, UF/IFAS
We all know that when you have bare ground in Florida, eventually something unwanted moves in or the soil moves out. To avoid either of these negative outcomes, a good practice is to grow robust vegetative groundcovers, especially if the soil slopes and is at high risk of eroding. Turfgrass is one option, but what if you don’t enjoy caring for a lawn or the site is difficult to maintain or even unsafe to mow? An often overlooked option in our area is Shore Juniper Juniperus conferta.
Although some people find this plant less than exciting, its easy to explain why it can be a good option in certain situations.
- Easy to find at nurseries
- Inexpensive
- Low water requirements once established (you’ll need to turn the irrigation off on these!)
- Salt tolerant
- Evergreen
- Cold tolerant
- Low, spreading growth habit (won’t block view)
- Do not require pruning (junipers cannot tolerate heavy pruning!)
A common cultivar of shore juniper is Blue Pacific Juniper which grows to be about one foot tall but spreads two to three feet wide. The new foliage has a blue cast that gives it the common name. It creeps along the ground and will provide good ground cover to sloping sites. This plant should be planted on 3 foot centers so they have room to expand without crowding. Plant in well-drained soil and apply two inches of mulch on bare soil between plants to reduce weeds while the plants are filling in. Only water until established, then stop automated irrigation and only water as needed. Read more at Establishing Shrubs Florida Landscapes.
by Carrie Stevenson | Jan 25, 2018
Ghost plant/Indian pipes emerging from the ground. Photo credit: Carol Lord, UF IFAS Extension
Imagine you are enjoying perfect fall weather on a hike with your family, when suddenly you come upon a ghost. Translucent white, small and creeping out of the ground behind a tree, you stop and look closer to figure out what it is you’ve just seen. In such an environment, the “ghost” you might come across is the perennial wildflower known as the ghost plant (Monotropa uniflora, also known as Indian pipe). Maybe it’s not the same spirit from the creepy story during last night’s campfire, but it’s quite unexpected, nonetheless. The plant is an unusual shade of white because it does not photosynthesize like most plants, and therefore does not create cholorophyll needed for green leaves.
In deeply shaded forests, a thick layer of fallen leaves, dead branches, and even decaying animals forms a thick mulch around tree bases. This humus layer is warm and holds moisture, creating the perfect environment for mushrooms and other fungi to grow. Because there is very little sunlight filtering down to the forest floor, the ghost flower plant adapted to this shady, wet environment by parasitizing the fungi growing in the woods. Ghost plants and their close relatives are known as mycotrophs (myco: fungus, troph: feeding).
Ghost plant in bloom at Naval Live Oaks reservation in Gulf Breeze, Florida. Photo credit: Shelley W. Johnson
These plants were once called saprophytes (sapro: rotten, phyte: plant), with the assumption that they fed directly on decaying matter in the same way as fungi. They even look like mushrooms when emerging from the soil. However, research has shown the relationship is much more complex. While many trees have symbiotic relationships with fungi living among their root systems, the mycotrophs actually capitalize on that relationship, tapping into in the flow of carbon between trees and fungi and taking their nutrients.
Mycotrophs grow throughout the United States except in the southwest and Rockies, although they are a somewhat rare find. The ghost plant is mostly a translucent shade of white, but has some pale pink and black spots. The flower points down when it emerges (looking like its “pipe” nickname) but opens up and releases seed as it matures. They are usually found in a cluster of several blooms.
The next time you explore the forests around you, look down—you just might see a ghost!
