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!
Many different Florida wildlife pass through a home landscape daily in search of food. Possibly the most destructive animal to landscape plants in northwest Florida is the White-Tailed Deer. Extensive amounts of damage can be observed after they have passed through. This damage is not just to landscapes but also impacts agriculture crops at an economic level.
Deer walking through a landscape in Northwest Florida. Photo Credit: Stephen Greer, University of Florida/IFAS Extension – Santa Rosa County
Deer are searching for protein that can be found in many forms that may include acorns from oak trees, ornamental shrubs, flowers, and soybeans. For this article, I will focus on landscape plants. Deer require a significant amount of forages as adults to amass 6 plus pounds per 100 pounds of body mass on a daily basis as they attain muscle and fat. Maintaining this level of growth is needed for quality reproductive rates and surviving the times of year, usually the winter, with less food available. Keep in mind damage is significantly lower from mid-spring to mid-summer with greater damage occurring from late-summer to late-fall.
Deer damage to a loquat tree. Photo Credit: Stephen Greer, University of Florida/IFAS Extension – Santa Rosa County
How to make informed plant decisions before placing them in the landscape and protecting many of these plants is a big question. There are many articles out there on selecting plants that are deer resistant or tolerant. Resistant to deer browsing is often dependent on how hungry they are and the amount of availability of other plants they prefer near by out of your landscape. With deer populations increasing significantly over the last few decades it has increased contact with people and the environments in which we live. To deter feeding and other damage to the landscape, fences have been placed as barriers, offensive smelling sprays have been used, lights and sounds have been used. The attempt is to offend more than one of the deer senses. These tactics work for a while until they adjust to these events and find their way back.
A barrier placed over a raised bed garden. Photo Credit: Stephen Greer, University of Florida/IFAS Extension – Santa Rosa County.
Some of the favored plants for deer include hosta, daylily, holly, and maple leaves and many more. Plants they tend to avoid are poisonous plants that include foxglove, poppies or fragrant plants from sage, salvias and bearded iris. There are publications with extensive lists of plants not to plant as they are a preferred food for deer and much shorter lists of plants they do not prefer. Contact your local UF IFAS Extension office for more information.
Deer, like many of the wildlife, were able to acclimate to neighborhoods and traffic settings. This has created additional dangers for many wildlife animals and people. The point is they are an established part of our communities. Determining how to best manage these growing populations has and will continue to be a big topic of discussion from neighbor to neighbor, community boards, farmers, and the Florida Wildlife Commission.
If you enjoy time spent outdoors, chances are you’ve come across a plant or two that has caused you to say, “That’s interesting! I wonder what that is?”. Identifying the plants you’re looking at can be a challenge, unless you happen to be a botanist. Even a handy book or reference guide can leave some room for confusion. You can always bring a picture or sample of a plant to your local extension office for help, but we also have some new tools available to help with identification. With the development of artificially intelligent software, we have apps on our cell phones that can do amazing things, including identifying living organisms.
There are some strange plants out there, and it might be difficult to learn what they are! (This one is Monotropa uniflora, the ghost pipe plant.)
There are a lot of options available, however, and cutting through the clutter is hard. To help decide which apps are the most trustworthy and effective, read on! Here are some plant identification apps that stand out currently:
There are a lot of dicots out there! Many can be identified quickly with the right app.
Free. Runs on Android devices (6.0 or later) or iOS devices (12.0 or later). This app requires an account, and combines artificial intelligence (AI) identification with a community of “citizen scientists” online who can help to confirm results.
Free. Runs on Android devices (6.0 or later) or iOS devices (11.0 or later). A more stand-alone version of the above app, this relies on AI to identify plants (and some animals and fungi).
Free to download, with a $2.99 monthly charge, $19.99 yearly charge, or $39.99 lifetime subscription for their premium version. Runs on Android devices (5.0 or later) and iOS devices (12.0 or later). PlantSnap relies on AI to identify plants using a database of over 600,000 plants and fungi.
Free. Runs on Android devices (5.0 or later) or iOS devices (11.0 or later). AI identification based on geographic area or plant theme (such as invasives, useful plants, etc.).
Free to download, 7 day free trial with $29.99 premium access. Works on Android devices (5.0 or later) and iOS devices (13.0 or later). AI provides immediate identification of over 10,000 plant species.
Free to download, with a $7.99 monthly fee or $35.99 yearly subscription. Works on Android devices (8.1 or later) or iOS devices (14.5 or later). Specifically tailored to houseplants, Planta includes plant identification as well as a light meter, care guides, and automatic reminders for houseplant care.
Free. Works with Android devices (6.0 or later) and iOS devices (14.0 or later). Among many other functionalities such as searching for consumer products, Google Lens is able to use its AI to identify plants.
Free. Usable only on iOS devices (15.0 or later). Included with the iOS 15.0 system, simply tap the info button on a photograph of a plant and then the leaf icon that appears. The iOS system will use its AI to attempt to identify the plant in question.
There are plenty more options out there and, as AI develops, more are undoubtedly on the way! Remember that not every identification, regardless of the software’s quality, might be accurate. Rare plants or those with many similar look-alikes could be mistaken. Use caution with these tools, especially for plants that might be harmful or toxic. While these can be a good starting point, it’s always a good idea to consult a knowledgeable human being (such as an Extension Agent or Master Gardener Volunteer) to be sure about any plant’s identity. Happy IDing!
I’ll be the first to admit that North Florida lawns are frustrating. With time, most people discover this.
Why are lawns so difficult here? The answer involves a combination of factors.
We are not far enough north to benefit from the better soils. Florida is known for sandy, low fertility, low water holding capacity soils. Some areas of the country enjoy richer soils with better water and nutrient holding capacities. These better soils result in a more favorable lawn root environment with roots being more competitive and resilient.
Something else happens in more northern areas. The heavier soils and colder temperatures (sometimes resulting in the soil freezing) are natural means of inhibiting and/or controlling certain soil dwelling pests. For example, nematodes are not nearly the concern in northern lawns. Many people that move to our area have never heard of these microscopic roundworms that play havoc in our low fertility, warm, sandy soils. After a lawn has been in place for a number of years, allowing the nematode population to reach a threshold, the lawn begins to decline. And we have few legal, effective chemical control options for nematodes in Florida lawns.
Declining area in lawn due to ground pearl. Photo credit: Larry Williams
Some other soil dwelling pests that northerners don’t have to deal with include ground pearls, small scale-like insects that bother centipedegrass roots. Mole crickets are not a pest much north of Central Alabama. Years ago, a representative with the company that manufactured the once popular mole cricket insecticide Oftanol told me that in the absence of the state of Florida, they would not sell enough Oftanol to keep it on the market. Take-all Root Rot, a common soil dwelling fungus, plays havoc in our Florida lawns and it is difficult to control.
We are not far enough north to use the more trouble-free northern grasses to create a permanent lawn. These include bluegrasses, fescues and perennial ryegrass. At best, these grasses can be used to overseed our lawns during the cooler fall and winter months to create a temporary winter lawn. But they will not survive our hot, wet summers.
We are not far enough south to benefit from the lack of freezing temperatures during winter. A late freeze that occurred on April 8 a number of years ago resulted in much lawn injury. I saw lawns with seventy percent kill from this late freeze. This is something that typically does not happen in Central and South Florida.
We deal with saltwater issues, high humidity, hurricanes and tropical storms, an array of lawn insects and diseases and extremes in rainfall and temperatures.
It’s no wonder most people become dissatisfied with their lawns. Perhaps we should lower our expectations and enjoy the natural flora and fauna of our state.
The ancient cycad, coontie, is a hardy and attractive plant for Florida landscapes. Photo credit: Carrie Stevenson, UF IFAS Extension
The plant has a crazy-sounding name, more like some little animal you’d find in Australia than a native plant. However, an ancient Florida plant it is, and a tough one at that. Growing close to the ground, it most resembles a large fern or a sago palm, if the sago had smooth, rounded leaf edges. Like the sago, the coontie (Zamia floridana) is a cycad—a group of palmlike plants that have been around so long that triceratops and stegasauruses ate them! Coonties are the only cycads native to North America, found in the states and island nations like Cuba and the Bahamas.
Male cones (strobilus) of coontie are thinner and shorter than female cones. Photo credit: Dan Culbert, UF IFAS
Another interesting feature of the coontie is its seed cones. These are large reddish orange cones that resemble magnolia seedpods. Both sexes of plant produce them in clusters ranging from one to five of the 2-7” long cones. Cones from the male produce pollen, while females produce seeds. If you are interested in attracting wildlife to your yard, the coontie provides good low-growing cover for birds and small mammals. It is also the preferred food for the caterpillar of the rare Atala butterfly. Members of the Timucuan and Calusa tribes ground up the starchy root of the coontie as a flour. However, the root contains a toxin and if it is not removed first, ingestion could result in severe abdominal pain and vomiting. From the late 1880’s through World War I, a large starch industry existed in Florida, producing flour from the coontie root.
Adult female atala butterfly, showing royal blue streak on forewings. Photo credit: Sandy Koi, University of Florida
At home in drier soil conditions like oak hammocks and pinelands in north central Florida, these plants can also adapt to a variety of soil pH types. Coonties are drought, cold, and salt tolerant, thus a great landscape choice for coastal landscapes near the Gulf or a bay. The plants are very long-lived and adaptable. In fact, the book Florida’s Best Native Landscape Plants notes it is “Very hardy and easy to care for. Will grow well in any part of Florida, even outside its normal range. An exceptional replacement for the closely related, often used, but non-native sago palm.” In other words, this is an ideal landscape plant that should be used more throughout Florida.
