One of the best parts about working at the Extension Office is all we learn from the questions we field from curious citizens. I recently had a question about ozone sensitivity in a plant and if that meant it shouldn’t be planted near a street. A little research had me learning all about this interesting topic and finding out that there are even ozone gardens being planted to monitor for air quality.
First of all, ozone (O3), also known as trioxygen, is the name we give when three oxygen molecules form a bond. It is present in low concentrations throughout the atmosphere and is important in absorbing ultraviolet (UV) radiation from the sun. This upper “ozone layer” is what we were concerned about when we noticed a hole forming in it, and regulations were put in place to minimize products that damaged this protective layer. However, ozone can also be formed lower in the atmosphere (called the troposphere) near the surface, where air pollutants, such as those related to the burning of fossil fuels and associated with smog, are produced. In this case, the ozone is considered a pollutant because it can cause health issues for animals, including humans, and can also affect plants.
Good ozone is way above our heads while the bad ozone is near the surface. Credit: National Center for Atmospheric Research.
When toxins in the environment harm plants, we call them phytotoxic. In the case of ozone, it can be phytotoxic at certain levels, and researchers are finding that certain plants seem to be more sensitive to ozone than others. The ozone damages plants by entering through the stoma, very small holes on the bottom of the leaves that the plant uses to pull in carbon dioxide and let out oxygen. Once inside the plant, ozone begins to alter normal cellular function, via oxidation, and causes visible symptoms, especially with the more sensitive plant species.
Symptoms of ozone phytotoxicity on tuliptree (Liriodendron tulipifera). Credit: USDA Forest Service – Region 8 – Southern , USDA Forest Service, Bugwood.org
These particularly sensitive species can be used as biological indicators because they show symptoms that can be easily recognized as ozone injury. Several National Parks and other public gardens have even begun installing ozone gardens, planted with these biological indicator species, to assess the air quality of the area.
Are you interested in knowing the plants that are sensitive to ozone? Here’s a list of species, selected from a National Park Service publication (Ozone Sensitive Plant Species on National Park Service Lands), that grow in the north Florida area:
Trumpet creeper (Campsis radicans)
Eastern Redbud (Cercis canadensis)
Flowering dogwood (Cornus florida)
Tuliptree (Liriodendron tulipifera)
American sycamore (Platanus occidentalis)
Black cherry (Prunus serotina)
Winged sumac (Rhus copallinum)
Cutleaf coneflower (Rudbeckia laciniata)
To answer the question that started this path down the ozone rabbit hole, the tree would likely be okay to plant near a road. The tree was not on the research-backed list and the ozone levels in our area generally low. Ozone levels in our part of the state average about 55-60 ppb (parts per billion), compared to the standard of 70 ppb, last set by the US Environmental Protection Agency (EPA) in 2008. Planting the tree may even be a fun, and useful, experiment to keep an eye on local air quality.
Ozone levels, as measured and reported by the Florida Department of Environmental Protection. Source: FDEP.
If you’re interested in more information on the impacts of ozone on plants, the National Center for Atmospheric Research has a great website, including a map of ozone gardens across the country. For more information on ozone levels across the country or in the state of Florida, the US EPA and the Florida Department of Environmental Protection (FDEP) have websites containing useful charts and maps. The good news is that surface ozone levels are generally on the decline thanks to regulations put in place to protect people and the environment. Of course, if you have any plant related questions, please contact your local extension office – we need article ideas!
In Florida, we have plenty of native critters trying to find their way into our homes – cockroaches, mosquitoes, lizards, squirrels, mice, and even alligators and bears every now and again. So, we don’t really need any more non-native critters to worry about, but we do. The Argentine ant is one of these non-native nuisances that can be quite difficult to control.
The Argentine ant is from South America and has become a pest worldwide. Although these ants don’t sting or bite, they can be a major nuisance in the home as they search for food and water. A unique feature that makes these ants especially difficult to deal with is that they form multi-queen colonies that can form a network of interrelated colonies. Unlike other ant colonies that may compete with each other, Argentine ants are able to spend less time defending their nests and more time looking for resources. These ants are also really small, with the workers only about 2.2 to 2.6 mm (around 1/10 of an inch). The Argentine ant emits a musky odor when crushed, helping to identify it among other small pest ants.
The Argentine ant is a small, nuisance pest ant that readily invades structures, especially during the warmer months. Credit: April Noble, from www.antweb.com.
These minute, cooperative ants can quickly invade a structure looking for food and water, especially when it warms up. At 70°F, it takes 25 days for the pupa to change into an adult compared to only 8 days at 86°F. This ability to reproduce quickly is a trait shared by most invasive species, whether plant or animal.
While not a health threat to humans, they are very annoying pest. In the home, they are attracted to sugars and oils and like to hide in the soil of potted houseplants. Outdoors, they nest in mulch, leaves, and rotting logs. You can often find them “tending” to insects on your outdoor landscape plants. The ants eat the sugary feces of sap-feeding insects, called honeydew, and provide these insects protection in exchange. In citrus groves, the Argentine ant has been known to help the Asian citrus psyllid better compete against predators, allowing this other invasive species to potentially spread citrus greening.
This Argentine ant is “tending” a scale insect. Credit: Alex Wild, University of Texas at Austin, alexanderwild.com
To help control the Argentine ant, you need to start with the perimeter of the home. It’s best to keep a 2’ barrier around the home free of leaves, mulch, woody debris, and landscape plants. This minimizes areas to nest near the home. If they begin to enter the home, place ant bait stations or gel baits along their trail. Argentine ants tend to like sweet baits. Broadcast pesticide spray treatments are not as effective because the nest is usually located far enough below ground where the pesticides can’t penetrate. Pesticide powder formulations are available to treat small crevices. These ants are difficult to control and you may want to consider hiring a professional pest management company for backup. For more information on the Argentine ant, it’s identification and control methods, please see the UF/IFAS Argentine Ant Factsheet. For any questions on ants or other structural pests, contact your local county extension office.
Many homeowners enjoy placing bird feeders in the landscape and filling them with purchased bird seed mixes to delight in observing the various visitors. In addition to our common songbirds, and maybe some rare migrating species that stop for a moment, you may also find some non-feathered species, such as the ever-troubling squirrels and an occasional snake. You may find some interesting and new plants popping up under the feeder, too.
Plant volunteers under the feeder are usually coming in from the bird seed itself. Hulled seeds, as well as any imported seeds, are less likely to sprout, but bags of purchased bird seed will generally provide an ingredient list, showing you the potential options. Based on my observations, along with a review of other articles and communication with local bird seed providers, the common plants you will see sprout under the feeder include millets, safflower, and sunflowers.
Proso millet (Panicum miliaceum) has a more open seed head than great millet (Sorghum bicolor). Credit: Adobe Stock.Great millet (Sorghum bicolor), also known as sorghum or milo, is a common bird seed ingredient. Credit: Adobe Stock.
Millet is a common name applied to various grain crops. Proso millet (Panicum miliaceum) and great millet (Sorghum bicolor), also known as sorghum or milo, are your most common millets in bird seed mixes. Proso millet is more preferred as bird seed since most birds tend to push aside the great millet. Lower cost bird seed products will often have the great millet, and this species will readily sprout under a feeder. In addition to feeding birds, the various millet crops are also used to feed humans throughout the world, with sorghum being the fifth most important cereal crop after rice, wheat, corn, and barley.
Safflower (Carthamus tinctorius) is a surprising find under the bird feeder. Credit: Adobe Stock.
Safflower (Carthamus tinctorius) is the bird feeder volunteer that sparked my interest in discovering the plants contained in bird seed. Safflower is readily gobbled up by Cardinals, Grosbeaks, Nuthatches, Finches, and Titmice. This daisy relative is native to the Mediterranean region and is one of human’s earliest cultivated crops used for dyes, seasoning (a substitute for saffron), oils, and, of course, bird seed.
A more common bird feeder volunteer are sunflowers (Helianthus annuus). There are many varieties of sunflowers that have been developed over the years. Bird enthusiasts mainly distinguish between black oil and striped sunflower seeds. These derive from either oil-producing varieties (black oil seeds) or what is known as confection sunflowers (striped seed). The oil-producing varieties were bred to produce sunflower oil and the seeds are generally smaller, have a higher oil content, and a thinner husk, all making them very attractive to a larger variety of birds. The confection sunflowers have larger seeds on larger heads and were bred to be easier for us humans to get into. For feeding birds, the confection varieties with the striped seed have a thicker husk and so are harder for many smaller birds to feed on. If you allow these to grow, both varieties can grow quite large, so be prepared.
In general, many bird enthusiasts will encourage you to clean these seeds up as they can attract unwanted wildlife, from unsavory birds, like Pigeons, Starlings, and Finches, to mice and raccoons. However, even a tidy feeder of birds will likely have some seeds germinate and may want to know what they are. It’s also great fun to watch the birds skip your feeder and go right to the source, picking millet or sunflower seeds right off the plant.
Providing a diverse landscape of native plants that occupy different vertical layers is beneficial for birds and other wildlife. Credit: NC State Extension.
While bird feeders should be considered a treat for your wild birds, like desserts on the top of the old food pyramid, they are still fun to set out in the landscape to provide a spot for you and your family and friends to observe wildlife. Remember that the best way to feed the birds is to provide a diverse landscape, especially one with many different vertical layers and native plant species. For more information on feeding birds, you can read the UF/IFAS document Attracting Backyard Birds: Bird Feeder Selection that contains information on the different types of bird feeders, but also on the various seeds. The UF/IFAS Gardening Solutions website also has a great page on Gardening for Birds.
Small debris recently littered area lawns, but these materials are no “trash”. Credit: Adobe Stock
Hurricane Idalia recently tore through the Big Bend area, battering the coast and taking down trees, leaving thousands out of power. While much of the panhandle was safe from the strong winds and storm surge, we still got some gusty weather, and likely had some amount of cleanup to do following the storm. Fortunately for us, this time, it’s mostly a lot of small branches and leaves versus entire trees that our fellow gardeners are cleaning up to the east of us. In addition to being thankful that larger branches didn’t fall here, consider turning those small bits and pieces over to wildlife while collecting your wheelbarrow loads of debris. This is a great opportunity to practice sustainable landscape practices and a few Florida-Friendly Landscaping Principles.
The UF/IFAS Florida-Friendly Landscaping Program has nine principles that it encourages Florida homeowners to practice in their landscape to conserves Florida’s natural resources. Three of the nine principles can be practiced by choosing how you manage the debris that has fallen – #4 Mulch, #5 Attract Wildlife, and #7 Recycle Yard Waste.
A mockingbird enjoys perching at the brushpile. Credit: Adobe Stock.
The first reaction when looking out at your landscape after a storm is typically “Ugh, there’s a lot of stuff to clean up.” We often want to “clean it up” and get it back to a sea of perfect cut grass, or at least sort of nice grass. However, the small branches and leaves that fall can be a great resource for wildlife, can provide mulch around a tree, and letting them rest reduces the need for you to haul all that stuff up to the road and all that goes into picking up, transporting, and processing the material.
The larger branches (four to six inches in diameter and larger) can be used for firewood or a naturalistic bed edging. Otherwise, they can go into a large brushpile. Smaller sticks and branches are perfect for one large brushpile, or, if a large pile doesn’t meet your aesthetic desires, a series of small piles scattered or hidden behind some shrubs is a good compromise. The leaves and really small stuff (branches no larger than a pencil) can be raked up for mulch, added to the brushpile(s), or just left in place to naturally rot away and/or get shredded up by the mower.
Many small, pencil size twigs, along with leaves, can be left in place as a mulch. Credit: Mark Tancig, UF/IFAS.
No matter how you leave the debris, consider how important this material is for all sorts of wildlife. Dead wood supports microbes, fungi, and animals up and down the food chain and even adds to your soil organic matter. While it may not look “clean” to us, those bits of “trash” are gold to many critters, especially small insects that bring birds to the yard. So, during cleanup, consider leaving little treats here and there for wildlife and spend less time hauling it to the road! For more information about the Florida-Friendly Landscaping Principles, visit the UF/IFAS Florida Friendly Landscaping Program website.
It’s hot, but the birds are still singing, the bees, including annoying yellow jackets, are buzzing, and the plants continue blooming. While many north Florida gardeners are hesitant to do much gardening in this heat, there’s plenty in the landscape to keep us entertained. One of the many benefits of gardening is observing all of the wildlife that visits, whether for pure enjoyment of watching nature or for keeping life lists of every bird, beetle, snake, or wildflower you’ve ever seen. However, many of us may not know exactly which bird, etc. that we’re looking at, much less hearing in the distance. Fortunately, there’s an app for that!
You may already be familiar with the many online tools, but here are a couple that are easy to use, assuming you know how to download an app on your smartphone, and go beyond an id based on visual similarity to other online photos with no consideration of your location.
We’ll start with my favorite app for plants, insects, and other critters you can easily capture with a camera – iNaturalist. Once you set up your account, you can begin to upload “Observations” with saved photos or directly with your phone’s camera. iNaturalist does have the option for uploading sound “Observations” as well, which I’ve used to upload frog calls. It uses your location to provide you with a list of potential species, and which one it feels is the most likely. The great thing about iNaturalist is someone else, often someone with experience identifying that organism, follows up to confirm or suggest another option. When enough identifiers agree, your “Observation” is considered research-grade. Another great feature of iNaturalist is that once the “Observations” are considered research-grade, biologists around the world can use the app to learn more about plant and animal population dynamics. Turning you into a research assistant/gumshoe naturalist. iNaturalist should only be used for wild populations, nothing planted or domesticated. They have a slimmed down version called Seek that can be used for identifying landscape plants.
List of “Observations” in iNaturalist. Credit: Mark Tancig, UF/IFAS.The INaturalist user interface when uploading a new species. Credit: Mark Tancig, UF/IFAS
Another easy-to-use app from our land-grant friends, and bird lovers, at Cornell University is the Merlin Bird ID app. The great feature of this app is the ability to record bird chatter and let the app figure out the bird species present. Once the recording is over, you can save it and even dial in on the different species and the call it made. With the touch of a finger, you can then learn more about each species. The Merlin Bird ID app also utilizes your location data and allows for uploading pictures and/or using a step-by-step guide to help figure out what you may have seen.
The Merlin Bird ID app allows you to record bird species by sound, photo, or with a step-by-step ID. Credit: Mark Tancig, UF/IFAS.The results of a sound recording from my backyard. Credit: Grace Diez-Arguelles.
The heat may be miserable, but the sounds and sights of the garden can be quite a treat this time of year. Once you learn more about the critters that share your landscape, hopefully you’ll be encouraged to provide them more of the things they need to thrive – water, shelter, and food, in the form of a diverse landscape. Maybe it will give you ideas for more plantings later, when it cools off a bit!
I should highlight that both apps are free with no obnoxious ads that pop up while you have them open. They both also allow you to make lists and keep track of your observations. When visiting a new part of the world, they also let you explore what species may be near and new to you.
