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.
Ken Langeland, left, and Martha Monroe, University of Florida environmental educators, examine an invasive tallow tree on Paynes Prairie near Gainesville, Thursday 10-19. They’re part of a team of researchers from UF’s Institute of Food and Agricultural Sciences and The Nature Conservancy training people how to manage environmentally sensitive lands. With more than 11-million acres of protected land, Florida needs more trained people to help protect those environmental jewels.
It is National Invasive Species Week, a time where everyone involved in natural resources, agriculture, and related fields works to raise awareness about this issue. It is an issue that costs huge sums of money to control and address, impacts economic sectors, and requires constant inspections at ports of entry to prevent new invasives from expanding the problem. Unfortunately for us, invasive species do not recognize international borders or state and local boarders for that matter. The same is true about property boundaries, which makes controlling them on the landscape difficult. They do not politely stop at the property line. So, what are we to do about the infestation when it crosses a boundary?
In Florida there is no law that requires someone to treat or remove an invasive species from the landscape. Laws do exist that prohibit the importation of species and that prohibit propagation and planting of know invasive species. Cost share programs, grants, and other efforts exist to assist private property owners and public land managers with invasive control programs and encourage the control and eradication of invasives across Florida’s landscape. Across Florida, organizations called Cooperative Invasive Species Management Areas (CISMA’s) exist to help coordinate efforts and provide educational outreach. The CISMA that covers Walton and the surrounding counties is the Six Rivers CISMA, and this outstanding organization even crosses state boundaries to include adjoining Alabama counties. This cross-state collaboration is an outstanding example of working across boundaries to accomplish a common goal. You can learn about the Six River CISMA and it’s efforts to invasive species through their website (LOCAL PRIVATE LANDS ASSISTANCE – Six Rivers Cooperative Invasive Species Management Area (floridainvasives.org) ). Our outstanding University of Florida IFAS extension service provides research and education across the state to help inform control efforts and coordinate through a network of experts from research professionals to local county extension agents. All of these efforts are making great progress in the control and management of invasive species.
One issue still stands out as a major challenge in taking on invasives, and that is that the ability to do control stops at a property line. This is especially true for some of our worst invasives like cogongrass, Japanese climbing fern, Chinese privet, and tallow tree; just to name a few. While animals move and you can trap or remove them as they come across your property; plants stay in place and often spread in an area. If that area happens to be right along a boundary, something like a fence row, the infestation often spreads across the property line. Add to that the fact invasive species, because of the disturbance and vegetation changes, often thrive and colonize in areas like fence rows and you have a major issue. That plant doesn’t see that posted sign and the property owner must stop any treatment effort at that point. Legally a landowner cannot cross a property line, and is liable for doing so especially when mowing, burning, or spraying herbicides. Putting herbicide on a neighboring property, even if it was accidental drift, is a major no go and can land the two parties in court. At best in this situation a property owner has a good relationship with neighbors and can work something out to control the infestation. If not, the treatment must stop where the ownership stops.
Why is it a problem that a treatment stops at the property boundary? Well, cogongrass is a great example. Cogongrass is a major problem in Walton County, and across the Panhandle in general. The western panhandle and southern Alabama are considered the epicenter of this invasive, and in Walton County it is spreading like wildfire. That’s somewhat literal too as this invasive grass massively increases fire intensity and spreads. My fellow extension agent from Gulf County, Ray Bodrey, just wrote a great article about this grass and the issues it is causing. I won’t duplicate his effort and expound on how to identify it. You can see his article here NISAW: A Spreading Menace in Gulf County, known as Cogongrass | Panhandle Outdoors (ufl.edu). Needless to say, if two county agents list it as one of the top issues, then we need to focus on it.
This grass spreads rapidly and easily, especially along roadsides, right of ways, and fencerows. You might wonder why that is? Well it happens to love to hitch a ride on equipment or move in contaminated fill dirt. Add to that it is tough to kill and takes multiple years of herbicide treatment to do the trick; and you have what has been identified as the Gulf Coast’s worst invasive. In fact, it is usually listed as one of the worst invasive species worldwide. Tack all that together and throw the fact that you cannot always work across a boundary and you’ve got quite the intractable issue. And that is just our top offender, we still haven’t touched tallow tree and the other of Six River CISMA’s “Dirty Dozen”.
What can be done then if invasives are such a herculean task that requires cross boundary management? We have several options, many of which I mentioned earlier in the article. Lots of work is being done right now by everyone from private landowners to local governments and even at the federal level. Here in Walton County the local public works has an active program to report and control cogongrass in the roadway and other county right of ways. They use in house and contract teams to report, track, and treat cogongrass infestations. This is a great effort and shows a great proactivity on the part of the county government. The program will go a long way in the congongrass control effort, but it still must stop at the right of way. If the infestation goes onto private property, it is then on the private property owner to have a control plan. Without some good communication the property owner may not even realize the problem is there.
Cogongrass is a good example of why it pays for a private landowner to treat an infestation too. This grass has no forage value and chokes out any other crops, lowering agricultural yields and values. It ruins yards, turf grass, and golf courses along with dulling and damaging mowing equipment. It contaminates fill dirt and borrow pits and then spreads to areas as development and construction occurs. If you are in the fill dirt business, clients that know usually reject soil that is contaminated or could be contaminated with cogongrass rhizomes. Forest landowners suffer major impacts from this invasive grass as it makes reforestation next to impossible, increases wildfire risk, makes using prescribed fire difficult at best, reduces timber yields, and ruins the habitat value for wildlife. An unchecked cogongrass infestation can ruin land values and it will do that as it spreads across onto other property.
This loss of land value is not just conjecture either. An article published in the Journal of Agricultural and Applied Economics from research performed by scientists from the University of Florida and the University of New York found that cogongrass infestations in slash pine forests reduce the return on investment and the land value. The study (Alavalapati et al 2007) looked at the impact of cogongrass infestation on rates of return and land values in several situations: no threat of infestation, infestation uncertain with no management, infestation uncertain with treatment by one landowner, and infestation uncertain with treatment by all landowners. The study found that cogongrass negatively impacts rental rates and the land value. To assess the land value, they used a forestry measurement called the Land Expectancy Value, which is a formula that uses the expected productivity of the land, input costs, and expected timber value to determine how valuable timberland is. The study found that the land value can be decreased by up to 50% on timberland. The study also found that the annual net returns per acre are decreased by between $17.00 and $25.00 depending on the infestation and management scenarios. Those are big economic and land value impacts, and that is just for forested lands. The big finding was that the scenario that resulted in the biggest loss of land value and returns was when only one landowner was treating. Alavalapati et al 2007 found that when control measures are undertaken by all landowners in an infestation zone the impacts are lowest and the most value is preserved. They suggest that the study results show the best outcomes will be when collaborative efforts are used. While the study only looked at cogongrass, the methodology and results are applicable to other invasive species. Working across that property line has real economic benefits as well as all the ecological and landscape benefits that come from invasive species control.
Donn Shilling and Eldridge Wynn look over a research field
of cogongrass, which has become a problem for cattle ranchers.
Practical experience shows that this collaborative approach works as well. Since 2004 the Georgia Forestry Commission and the State of Georgia have implemented a cogongrass task force. Georgia recognized the severity of the issue early on, to some degree from seeing what was occurring in Florida and Alabama. They also recognized the state could not completely prevent cogongrass from entering the state but could be proactive at control and eradication. They launched a collaborative effort lead by the Georgia Forestry Commission, where landowners and others would report congongrass and the infestation would be identified and treated at no cost to the landowner. The program was structured where they could work with other landowners at an infestation site as well. The program also implemented a tracking and follow up program, which tracked the infestation until it was eradicated or became inactive. In 2007, 72 Georgia counties had detections, but as of 2021, 34 of those 72 have no active cogongrass and 85% of all known cogongrass spots in Georgia are inactive (2021-Dirty-Dozen-List.pdf (gatrees.org). That is a huge success and something that can be replicated in other states. This program took federal and state funding, state and local government involvement, coordinated tracking, and reporting and detection from landowners. It could not have happened without this collaborative effort that reached across boundaries.
Could we see something like this in Walton County or across the Panhandle? Absolutely, we could definitely build a collaborative effort on one or more invasives. Cogongrass is a great place to start, and even though it is so difficult to eradicate we have evidence that a program can be successful. What it takes is reaching across boundaries and the “Think Global, Act Local” approach, or as the Florida Invasive Species Partnership puts it “Think Locally, Act Neighborly”. Florida does not have a statewide coordinated cogongrass control effort like Georgia, but the nature of the issue in Florida is very different. Given the size and scope, a Florida eradication program would likely look much different. But why wait for a statewide program like Georgia? It would be much easier to replicate a cooperative program on invasive species at the county level. It will take working across boundaries and communicating across communities and ownerships; but we know it works. The bottom line is that inaction will result in a growing and extending problem, spreading across more and more ownerships and areas. Invasives are not just an ecological or environmental problem either, they impact land values and our economy too. The information we have shows that when control efforts are sporadic and individual; economic impacts are actually higher because landowners controlling the invasive incur costs while infestations persist in an area. To keep our land base productive and valuable we have to work together and take community efforts. This is everything from identifying and tracking infestations to control and monitoring. If it can work with cogongrass, it will work with the other major invasives as well. Most of our greatest achievements as Americans, things like making it through the Great Depression, building the Transcontinental Railroad, or winning World War II, have been through collaborative efforts. Invasive species control is going to be the same thing, and research and results on cogongrass show reaching across boundaries works. Invasives move across boundary lines; so we need to work across them to be successful. A collaborative cogongrass effort would be a great start, and then we can expand.
References and Resources
Alavalapati, J. R. R., Jose, S., Stainback, G. A., Matta, J. R., & Carter, D. R. (2007). Economics of Cogongrass Control in Slash Pine Forests. Journal of Agricultural and Applied Economics, 39(s1), 61–68. https://doi.org/10.1017/s1074070800028947
Cogongrass continues to be a thorn in the side of many landowners and municipal public works departments, as it spreads in areas across the Panhandle, with Gulf County being no exception. Thankfully, there are ways to combat cogongrass, but it seems to be an uphill battle. Identifying and being persistent with treatment are paramount in control.
Figure 1: Cogongrass infestation and uneven mid-rib in leaf blade.
Credit: Ray Bodrey, UF/IFAS Extension Gulf County.
Cogongrass (Imperata cylindrica) is found all over the world. In the U.S, it is primarily found in the southeast. Cogongrass was purposely introduced as a soil stabilizer for pasture lands in Florida during the 1930’s and 1940’s. It wasn’t long before ranchers and agricultural scientists realized that cogongrass was an invasive species. Once established, cogongrass has the ability to overrun pastures and natural areas to the point that it will be the only plant species occupant. It’s a perennial grass with a vast, ever expanding root system. This grass can grow in any soil type and low soil fertility nor drought, are concerns either. Therefore, it thrives no matter how poor the soil environment. Even with multiple days of periods of well below freezing temperatures and a prior application of herbicide, figures 1 & 2 display the resiliency of cogongrass. The major concern is the ability to eliminate native plant habitat.
Cogongrass can be confused with other grasses, like switchgrass. This is especially possible early in the year before the bloom. To identify cogongrass, first investigate the growing pattern. It usually infiltrates an area in patches. As shown in figure 1, the grass blades are flat and have a defining white mid-rib. Blades are finely serrated, yellow to green in color and are uneven in width on each side of the mid-rib. The seed head is fluffy, white and feather shaped. The seed head can alarmingly yield 3,000 seeds per head.
Figure 2: Cogongrass spreading.
Credit: Ray Bodrey, UF/IFAS Extension Gulf County.
The management strategy most successful with eradicating cogongrass consists of multiple types of herbicides sprayed over multiple year applications, with additional spot treatments. Prescribe burning can also be used in concert as an integrated approach.
For control measures, see the tables in the document referenced below. Also, contact your local county extension agent for further details.
Information for this article is from the UF/IFAS EDIS publication: “Cogongrass (Imperata cylindrica) Biology, Ecology, and
Spring can be a busy time of year for those of us who are interested in improving wildlife habitat on the property we own/manage. Spring is when we start many efforts that will pay-off in the fall. If you are a weekend warrior land manager like me there is always more to do than there are available Saturdays to get it done. The following comments are simple reminders about some habitat management activities that should be moving to the top of your to-do list this time of year.
Aquatic Weed Management – If you had problematic weeds in you pond last summer, chances are you will have them again this summer. NOW (spring) is the time to start controlling aquatic weeds. The later into the summer you wait the worse the weeds will get and the more difficult they will be to control. The risk of a fish-kill associated with aquatic weed control also increases as water temperatures and the total biomass of the weeds go up. Springtime is “Just Right” for Using Aquatic Herbicides
Cogongrass Control – Spring is actually the second-best time of year to treat cogongrass, fall (late September until first frost) is the BEST time. That said, ideally cogongrass will be treated with herbicide every six months, making spring and fall important. When treating spring regrowth make sure that there are green leaves at least one foot long before spraying. Spring is also an excellent time of year to identify cogongrass patches – the cottony, white blooms are easy to spot. Identify Cogongrass Now – Look for the Seedheads; Cogongrass – Now is the Best Time to Start Control
Cogongrass seedheads are easily spotted this time of year. Photo credit: Mark Mauldin
Warm-Season Food Pots – There is a great deal of variation in when warm season food plots can be planted. Assuming warm-season plots will be panted in the same areas as cool-season plots, the simplest timing strategy is to simply wait for the cool-season plots to play out (a warm, dry May is normally the end of even the best cool-season plot) and then begin preparation for the warm-season plots. This transition period is the best time to deal with soil pH issues (get a soil test) and control weeds. Seed for many varieties of warm-season legumes (which should be the bulk of your plantings) can be somewhat hard to find, so start looking now. If you start early you can find what you want, and not just take whatever the feed store has. Warm Season Food Plots for White-tailed Deer
Deer Feeders – Per FWC regulations deer feeders need to be in continual operation for at least six months prior to hunting over them. Archery season in the Panhandle will start in mid-October, meaning deer feeders need to be up and running by mid-April to be legal to hunt opening morning. If you have plans to move or add feeders to your property, you’d better get to it pretty soon. FWC Feeding Game
Dove Fields – The first phase of dove season will begin in late September. When you look at the “days to maturity” for the various crops in the chart below you might feel like you’ve got plenty of time. While that may be true, don’t forget that not only do you need time for the crop to mature, but also for seeds to begin to drop and birds to find them all before the first phase begins. Because doves are particularly fond of feeding on clean ground, controlling weeds is a worthwhile endeavor. If you are planting on “new ground”, applying a non-selective herbicide several weeks before you begin tillage is an important first step to a clean field, but it adds more time to the process. As mentioned above, it’s always pertinent to start sourcing seed well in advance of your desired planting date. Timing is Crucial for Successful Dove Fields
There are many other projects that may be more time sensitive than the ones listed above. These were just a few that have snuck up on me over the years. The links in each section will provide more detailed information on the topics. If you have questions about anything addressed in the article feel free to contact me or your county’s UF/IFAS Extension Natural Resource Agent.
We’re waging war on an invasive weed, Cogongrass. Cogongrass was accidently brought into Mobile, Alabama in the early 1900’s as packing material. It was later planted in Florida and other states as a potential forage and soil stabilizer. It has low forage value and is on the Federal Noxious Weed List.
This weed can spread through both creeping rhizomes and seeds. It quickly displaces desirable grasses and plants. The roots of Cogongrass may produce allelopathic chemicals helping it out-compete other plants for space. It is drought and shade tolerant. A single plant can produce 3,000 seeds. Cogongrass is yellow/green in color with an off-set midrib and a fluffy white seed head and it grows in circular colonies.
Mowing and burning will not eradicate Cogongrass instead doing so while the plants are flowering can cause spread of seeds. Herbicide options are non-selective and kill most native ground cover such as grasses. Ridding an area of a Cogongrass infestation requires intensive management. For small infestations (less than 20-30 feet in diameter), treat the area with glyphosate once in the fall and once in the spring for 3 years (or until eradicated). For larger infestations, a more integrated approach may be necessary. Deep tilling of the soil may help in some cases.
Cogongrass is not easy to control. It takes a coordinated effort from government agencies and private landowners to work together to rid an area of this invasive weed. For more information, you can go to https://edis.ifas.ufl.edu/wg202 or contact your local extension agent.
