Without question, Cogongrass is the most troublesome invasive plant that I (and my clients) deal with. Here in Northwest Florida, we have a lot of it, and it is very difficult to manage. It has been my observation that the difficulty of management and limited early success often lead to frustration and ultimately a loss of interest in control efforts on the part of landowners/managers. This is the absolute worst-case scenario, as diligence over time is paramount to successfully managing cogongrass. With all this in mind, optimizing the impact of the initial control effort is crucial both in terms of biology (efficacy on the plants) and psychology (keeping the landowner encouraged and motivated). If you have cogongrass to fight, take every step you can to get the absolute best results you can, out of every treatment, especially the first one.
Cogongrass is highly invasive, difficult to control and widespread in Northwest Florida.
Phot Credit: Mark Mauldin
The following is a discussion of some of the steps you can take to maximize the efficacy of your control efforts.
1) Timing Matters
Cogongrass is best treated with a fall-spring, one-two punch. Mid-summer and mid-winter treatments are not advisable. NOW is the time to treat. As I write this it is mid-October with rain on the way – by the time this is published the front will have passed and the timing will be perfect. If you ask me the absolute best time of year to treat cogongrass, I will tell you, without hesitation, “October through November, before first frost, with good soil moisture”. Spray now and be prepared to spray again in the spring when you have at least 12 inches of green leaf and good soil moisture. With that one-two successfully delivered you should see significant reduction in the size of the infestation by this time next year. Keep repeating the spring-fall process until you can no longer find any cogongrass.
Getting good herbicide coverage over all of the characteristically lime green foliage of cogongrass is essential for good control.
Photo Credit: Mark Mauldin
2) Coverage & Leaf Area are Crucial
To make the most out of each treatment you must maximize the amount of chemical you get into the plant. This is done by getting thorough coverage on as much green leaf area as possible. Make sure you have plenty of green leaves (at least 12inches) and spray them like you’re painting a wall. You don’t want runoff, but you want every square inch of leaf covered with spray. Don’t mow or burn for at least 30 days after you spray. Cogongrass can be hard to spot, especially if it is growing mixed with other grasses/green foliage. Look diligently to find the edge of the patch and then spray 10ft past the known edge on all sides of the patch.
3) Get the Spray Mixture Right
Notice, I didn’t say pick the right chemical. There’s more to it than that. The following recommendations will be based on using the active ingredient glyphosate. (Imazapyr is also very effective on cogongrass, but due to its soil activity it is inherently more complicated to use and ensure the safety of desirable plants near the treatment area. I am not comfortable recommending imazapyr without first seeing the site where it is to be applied and discussing the risk to other vegetation with the landowner. Glyphosate must enter a plant through a green leaf making it much easier for applicators to ensure the safety of desirable vegetation.)
Generally speaking, the efficacy of glyphosate will increase if a water conditioner and surfactant are included in the spray solution. To clarify, this would be 3 separate products going into the spray tank – one herbicide and two adjuvants. The preferred water conditioner would be a 34% liquid Ammonium Sulfate (AMS) product and the surfactant would be an 80/20 Non-ionic surfactant (NIS). These products should be available anywhere ag chemicals are sold (not the garden center at a big box store) under many different name brands. Selecting a glyphosate product can be somewhat confusing, simply because there are so many different products on the market. The product amounts listed below are based on a 41%, 3lbs acid equivalent (ae) per gallon glyphosate product. This is a relatively common formulation, but there are many others available. All can be effective; it is just a matter of value and correctly adjusting the rate to match the formulation you are using.
An example mixture for treating a small patch with a hand-held single nozzle sprayer:
Fill spray tank ½ – ¾ full of water (run agitation if available)
For each gallon of spray solution you are making add:
3.2oz of 34% AMS water conditioner (add this first and let it completely mix before proceeding)
5oz of 41% 3lbs ae glyphosate herbicide
0.5oz of 80/20 NIS
Finish filling spray tank
For a broadcast application using a tractor mounted sprayer or other similar equipment, mix a spray solution such that 1 gallon of 41%, 3lbae glyphosate herbicide is applied per acre. Ideally this would be delivered in 10-20 gallons of water (be sure spray equipment is properly calibrated). Add a liquid AMS water conditioning product at 2% v/v before adding herbicide to the tank. Add a non-ionic surfactant (80/20 NIS) at 1qt per 50-100 gallons of spray solution after the herbicide has been added.
I understand that nobody likes to have to deal with all the numbers, especially the various formulations of glyphosate. Unfortunately, that’s just part of it… There are so many different products out there that the numbers are necessary to communicate the recommendations in a way that is widely applicable. Please don’t hesitate to contact me or your local UF/IFAS Extension Agent for assistance sourcing vegetation management products or tailoring the recommendations to match the specific products you have on hand. The most important thing is to get the mixture right and make the application be as effective as possible.
It’s a national program where volunteers gather at a public space to help remove invasive weeds. In many cases they target one specific species. This year in Escambia County we plan to target beach vitex on Pensacola Beach. If there is not an event in your community, you can still participate by removing invasive weeds from your own private property. Here is how…
Target one specific species. Maybe Chinese tallow, Japanese climbing fern, or other possible invasive weeds in your community. If you are not sure which weeds are invasive, check with your local county extension office.
Read how to best manage. Each species may use different methods and herbicides to treat. Maybe you do not want to use herbicides, not a problem, by visiting the website of the University of Florida’s Center for Aquatic and Invasive Plants, you can find fact sheets that will give you not only the different herbicides that can be effective, but other non-herbicide management ideas.
Decide what you are going to do with the weeds afterwards. Fragments and seeds from these weeds can generate new populations. You make sure you dispose of the plant properly to not create a bigger problem.
Pick a nice day, collect all your supplies, and do it.
Let us know! Contact me (Rick O’Connor roc1@ufl.edu) and let us know which species you removed and how much.
If you are in Escambia County and want to participate in our event this year, we will be removing beach vitex from public areas on Pensacola Beach. You will need gloves, loppers or clippers, and a 5-gallon bucket. Here is our schedule…
Oct 4 12:00pm Quietwater Boardwalk. Meet at the seashell.
Oct 12 12:00pm The Bike Path near the Sugar Bowl. Meet at parking lot 27A (Allen Levin Way).
Oct 18 12:00pm The sewer lift station on Via DeLuna just west of the west entrance into
Sugar Bowl.
Oct 25 12:00pm Bike Path near Portofino. Meet at parking lot 27B.
If you plan to come to one of these, let me know! Rick O’Connor at roc1@ufl.edu.
Vitex beginning to take over bike path on Pensacola Beach. Photo credit: Rick O’Connor
Miami is ground zero for invasive species in this state. But the Florida panhandle is no stranger to them. Where they are dealing with Burmese pythons, melaleuca, and who knows how many different species of lizards – we deal with Chinese tallow, Japanese climbing fern, and lionfish. The state spends hundreds of thousands of dollars each year battling and managing these non-native problem species. By definition, invasive species cause environmental and/or economic problems, and those problems will only get worse if we do not spend the money to manage them. Those who work in invasive science and resource management know that the most effective way to manage these species is to detect them early and respond rapidly.
The Invasive Species Curve
Invasive species have made their way to the coastal waters and dunes of the barrier islands in the Florida panhandle. Beach vitex, Brown anoles, and Chinese tallow are found on most. Recently on Perdido Key near Pensacola, we found a new one – cogongrass.
Cogongrass (Imperata cylindrica) was accidentally introduced to the Gulf coast via crates of satsumas entering the port of Mobile in 1912. It began to spread from there and has covered much of the upland areas of the southeastern U.S. It has created large problems within pasture lands, where livestock will not graze on it, and in pine forest where it has decreased plant and animal biodiversity as well as made prescribed burning a problem – it burns hot, hot enough to actually kill the trees. The impacts and management of this plant in that part of the panhandle has been known for a long time. The Department of Agriculture lists it as one of the most invasive and noxious weeds in the country.
Cogongrass seedheads are easily spotted in spring.
Photo credit: Mark Mauldin
Two years ago cogongrass was discovered growing around a swimming pool area at a condo on Perdido Key. To be considered an invasive species you must (a) be non-native to the area – cogongrass is certainly non-native to our barrier islands, (b) have been introduced by humans (accidentally or intentionally) – strike two, we THINK it was introduced by mowers. This is a common method of spreading cogongrass, mowing an area where it exists, then moving those mowers to new locations without cleaning the equipment. We do not know this is how it got to the island, but the probability is high. Third, it has to be causing an environmental and/or economic problem. It certainly is north of the I-10, but it is not known what issue it may cause on our barrier islands. Could it negatively impact protected beach mice and nesting sea turtle habitat? Could alter the integrity of dunes to reduce their ability to hold sand and protect properties. Could it overtake dune plants lowering both plant and animal diversity thus altering the ecology of the barrier island itself? We do not know. What we do know is that if we want to eradicate it, we need to detect it early and respond rapidly.
According to EDDMapS.org – there are 75 records of cogongrass on the barrier islands, and coastal beaches of the Florida panhandle. This is most likely under reported. So, step one would be to conduct surveys along your islands and beaches. Florida Sea Grant and Escambia County of Marine Resources are doing just that. EDDMaps reports five records on Perdido Key and four at Ft. Pickens. It most likely there is more. A survey of the northeast area of Pensacola Beach (from Casino Beach east and north of Via De Luna Drive) has found two verified records and two unverified (they are on private property, and we cannot approach to verify). Surveys of both islands continue.
The best time to remove/treat cogongrass is in the fall. The key to controlling this plant is destroying the extensive rhizome system. In the upland regions, simple disking has been shown to be effective if you dig during the dry season, when the rhizomes can dry out, and if you disk deep enough to get all of the rhizomes. Though the rhizomes can be found as deep as four feet, most are within six inches and at least a six-inch disking is recommended. Depending on the property, this may not be an option on our barrier islands. But if you have a small patch in your yard, you might be able to dig much of it up.
Chemical treatments have had some success. Prometon (Pramitol), tebuthurion (Spike), and imazapyr have all had some success along roadsides and in ditches north of I-10. However, the strength of these chemicals will impede new growth, or plantings of new plants, for up to six months. There are plants that are protected on our islands and on Perdido Key any altering of beach mouse habitat is illegal. We certainly do not want to kill plants that are holding our dunes. If you feel chemical treatment may be needed for your property, contact the county extension office for advice.
Most recommend a mixture of burning, disking, and chemical treatment. But again, this is not realistic for barrier islands. Any mechanical removal should be conducted in the summer to remove thatch and all older and dead cogongrass. As new shoots emerge in late summer and early fall herbicides can then be used to kill the young plants. Studies and practice have found complete eradication is difficult. It is also recommended not to attempt any management while in seed (in spring). Tractors, mowers, etc. can collect the seeds and, when the mowers are moved to new locations, spread the problem. If all mowing/disking equipment can be cleaned after treatment – this is highly recommended.
Step one would be to determine if you have cogongrass on your property, then seek advice on how to best manage it. For more information on this species, contact your local extension office.
Discover the fascinating world of Cuban Treefrogs and join us for an exciting workshop aimed at effectively managing their invasion. Led by Dr. Steve Johnson, an expert on Cuban Treefrogs from UF/IFAS Extension, this workshop will provide you with valuable insights on recognizing these invasive frogs and exploring management options. In addition, attendees will have the opportunity to learn how to monitor and report data on Cuban Treefrog populations. Together, let’s take action to address the challenges posed by the invasion of Cuban Treefrogs! The Workshop will be held September 28th 9am – 3pm CDT at 2728 E14th St, Panama City, FL 32401Register Here
The Invasion of Cuban Treefrogs:
Originating from Cuba and introduced unintentionally to Florida in the 1920s, the Cuban Treefrog has rapidly established itself across various states, including Georgia and Louisiana. Believed to have arrived as stowaways in shipping crates, these non-native frogs have become a cause for concern due to their impacts on native treefrog and toad populations.
Understanding the Threat:
Cuban Treefrog adults and their tadpoles are known predators of native treefrogs and toads. Their presence poses a significant threat to the delicate balance of our ecosystems. Therefore, it is crucial to develop effective management strategies to curb their invasion and minimize their impact on our native species.
Workshop Highlights:
During the workshop, Dr. Steve Johnson, an esteemed authority on Cuban Treefrogs, will guide participants through the identification and management of these invasive frogs. Attendees will gain valuable knowledge and practical skills to recognize Cuban Treefrogs and explore options for effectively managing their populations. Participants will also build and take home their own treefrog house (refugia) made with PVC.
Contributing to Research:
In addition to learning about identification and management, workshop attendees will have the opportunity to play an active role in monitoring and reporting data on Cuban Treefrog populations. By actively participating in data collection efforts, you will contribute to scientific research and provide crucial insights into the distribution and behavior of these invasive frogs.
Join the Cause:
The invasion of Cuban Treefrogs is a pressing environmental issue that requires collective action. By attending our workshop, you can become an agent of change in addressing this invasive species. Let’s work together to protect our native treefrogs and toads by effectively managing the population of Cuban Treefrogs.
Don’t miss out on this unique opportunity to join Dr. Steve Johnson and fellow nature enthusiasts in our workshop focused on managing the invasion of Cuban Treefrogs. By acquiring knowledge, developing practical skills, and contributing to data collection efforts, you can actively participate in protecting our native species and preserving the delicate balance of our ecosystems. Together, let’s make a difference and tackle the challenges posed by the Cuban Treefrog invasion. Register now and be a part of this important environmental initiative!
An invasive Cuban Tree Frog specimen. Invasive species, amphibians and reptiles. frogs, pests. UF/IFAS Photo by Tyler Jones.
The Emerald Coast Open Lionfish Tournament May 20-21, 2023, at HarborWalk Village in Destin, FL, is gearing up to tackle a pressing ecological challenge while showcasing the power of sport to make a positive impact. This unique tournament, held along the picturesque shores of the Emerald Coast, focuses on combating the invasive lionfish population in the region’s waters.
Lionfish, native to the Indo-Pacific region, have become a significant threat to the delicate balance of marine ecosystems in the Gulf of Mexico. With their voracious appetite and rapid reproduction, these invasive species pose a grave danger to native marine life. The Emerald Coast Open Lionfish Tournament aims to address this issue by encouraging divers and fishermen to actively hunt and remove lionfish from the waters.
Participants in the tournament will compete to catch the most lionfish, utilizing their skills in underwater navigation, spearfishing, and conservation. Sponsors provide cash and prizes for multiple categories including most caught, largest and smallest lionfish. The event provides an exciting platform for experienced divers and newcomers alike to contribute to the preservation of the marine environment.
Beyond the ecological significance, the tournament also offers a thrilling experience for both participants and spectators. Divers equipped with their spears dive into the depths, searching for lionfish while showcasing their prowess and bravery. The tournament fosters a sense of camaraderie and shared purpose among the participants, creating a community dedicated to the cause of protecting marine ecosystems.
In addition to the competitive aspect, the Emerald Coast Open Lionfish Tournament promotes education and awareness about the invasive species. Participants and attendees have the opportunity to learn about the impact of lionfish on local marine life and explore sustainable solutions to combat the issue at the free Lionfish Awareness Festival from 10:00-5:00 each day. Sign up to volunteer at the event if you want to join the fun. The week prior to the tournament is dedicated to Lionfish restaurant week where local restaurants practice the “eat ‘um to beat ‘um” philosophy and cook up the tasty fish using a variety of innovative recipes.
The Emerald Coast Open Lionfish Tournament 2023 represents a unique fusion of sport, environmental conservation, and community engagement. By bringing together individuals passionate about marine conservation, this event serves as a powerful catalyst for change and a shining example of how sport can contribute to the preservation of our natural world. Learn more at https://emeraldcoastopen.com.
A Lionfish Removal and Awareness Day festival volunteer sorts lionfish for weighing. (L. Tiu)
Donn Shilling and Eldridge Wynn look over a research field
of cogongrass, which has become a problem for cattle ranchers.
Cogongrass is one of our larger invasive species here in the Panhandle, and spring is a good time to detect and treat it. If you know or suspect your property may have cogongrass, spring is the best time to hunt it down and locate the spots and infested areas. It is also a great time to patrol your property boundaries as well to see if you have any that may be coming onto your property from a neighbor or right of way. Cogongrass seems to love fencerows and right of ways as it spreads easily on equipment through its tough rhizomes. One of the best ways to prevent large infestations from taking over portions of your property and creating a significant control cost is to catch it early. The key to this is to identify and mark small spots before they expand; and then follow up with herbicide treatment once to twice a year. Spring is an excellent time to go and scout for cogongrass and get a jump on this invasive for several reasons.
A relatively new patch of cogongrass recently found in Washington County.
Photo Credit: Mark Mauldin
One feature of cogongrass that is very distinctive is the seed head. In spring cogongrass flowers and puts up a cottony white seed head. These seed heads look like an elongated fluffy white tuft on a tall stalk. Once you have seen them for the first time you will instantly recognize this invasive grass. If cogongrass has been mowed, it can sometimes be hard to spot especially in a pasture. In spring the seed heads will quickly draw your attention to an area infested with this grass. It is very distinctive, and you do not see other grasses with this type of seed head the same time of year.
Other distinguishing features of cogongrass include a bright green color sometimes with red edges. In the spring the new growth of cogongrass is very prominent and stands out due to its bright color and usually faster growth compared to other grasses. The midrib of the grass blade is also usually offset to one side, another identifying feature. If you have a shovel handy you can dig up a small amount and you will notice thick rhizomes with sharp pointed tips. Once you learn to identify cogongrass and know what you are looking for; you can go out on your spring cogongrass patrol to identify any areas of infestation.
Cogongrass shown here with seedheads – more typically seen in the spring. If you suspect you have cogongrass in or around your food plots please consult your UF/IFAS Extension Agent how control options.
Photo credit: Mark Mauldin
Once you have identified an infestation you need to do three things: mark the impacted area with a flag or other noticeable method, record the location (by description or GPS), and develop a treatment plan. Marking and recording the location of cogongrass infestations, especially a small spot that is new, is critical to the success of control efforts. Cogongrass is tough and requires multiple treatments with herbicide to effectively control it and hopefully eliminate the infestation. This means you need to know where a patch is, be able to relocate and monitor it, and consistently treat the same spot to ensure you achieved complete control. Cogongrass control is easier when the spot is small and has not become well established. With small spots it can be difficult to locate the spot again the next year, especially after a round of herbicide treatment, so good marking combined with a GPS location or description is essential. Once you have gone back to a spot several years and the spot has not come back after treatment; you can consider the spot controlled. If you stop treatment and monitoring before cogongrass has been controlled for several years, the infestation will return from remaining rhizomes and spread all over again.
Consistent treatment with effective herbicides is the best way to ensure cogongrass is controlled on your property. If you locate some while scouting this spring be prepared to start a treatment program. Cogongrass responds to herbicides with the active ingredients glyphosate or imazapyr. These can be used alone or in combination. The spring and fall are the two treatment windows that are most effective. If you treat in the early spring when new growth is vulnerable you can sometimes prevent seed heads from maturing. You can also get some control that can help prevent heavy growth over the summer, which can be an advantage if you have to mow or maintain the area. Spring treatment is usually best accomplished with glyphosate alone, imazapyr alone or a mixture of both can be used.
Once we progress into summer, treatments with herbicide will mostly top kill the grass and do not provide effective control. Treatment in the fall with imazapyr alone or in combination is the most effective treatment method. If you identify infestations in the spring you can mark them and come back in the fall to get the most bang for your buck with treatments. You can apply a spring and fall treatment in one year if you want to accomplish some control in the spring, but this method is not necessarily more effective than the fall treatment alone. When using imazapyr herbicide you should be aware that this is soil active and has the potential to damage surrounding vegetation and hardwood trees that are in and near the treatment area. Pines are tolerant of imazapyr but can be damaged if high rates are used, and longleaf pine is more sensitive than others. When treating cogongrass with imazapyr be aware that damage to other vegetation could occur. If the cogongrass is in an area with hardwood trees or other sensitive vegetation glyphosate alone is a good alternative herbicide treatment. When using any herbicide be sure to read and follow the label correctly, follow all label directions, and wear proper protective equipment. There are several IFAS EDIS publications on cogongrass control which provide more detailed information: for control in pasture areas follow this link SS-AGR-52/WG202: Cogongrass (Imperata cylindrica) Biology, Ecology, and Management in Florida Grazing Lands (ufl.edu) and for control in forested areas follow this link FR342/FR411: Biology and Control of Cogongrass (Imperata cylindrica) in Southern Forests (ufl.edu) . If you identify cogongrass on your property these publications will help you develop a treatment plan to control it. Early detection and treatment when infestations are small is key to getting this nasty invasive under control. Take advantage of this spring to identify, mark, and treat any cogongrass that may be getting a foothold on your property before it becomes a major infestation.
