by Daniel J. Leonard | Oct 8, 2021
Over the last decade or so, the Panhandle has been overrun, and I don’t just mean by the summer beach traffic. Rather, by an aggressive, exotic perennial grass that quickly displaces all native species, is not useful as a forage to wildlife or livestock, can spread by roots or seeds, and has no natural enemies. If you own property in the Panhandle or spend any amount of time on its roads, chances are you have become acquainted with this worst of invasive species, Cogongrass (Imperata cylindrica).
A native of Southeast Asia, cogongrass was introduced into the US in 1912 around Mobile, AL as a hitchhiker in orange crate packing. Then the 1920s, 30s, and 40s, it was intentionally introduced from the Philippines into other Gulf Coast states, including Florida, as a potential pasture forage for livestock. Since then, cogongrass has become one of the most economically and ecologically important invasive species in the US and worldwide, infesting nearly 500 million acres and is now found on every continent.
Cogongrass in Calhoun County, FL. Photo courtesy of Daniel Leonard.
Cogongrass is easily identified in late spring, when the grass throws easily spotted fluffy, white-colored seedheads above the mats of grass beneath. Additionally, patches of cogongrass are almost always noticeably circular in nature, radiating out indefinitely from the initial infestation. A closer inspection of the grass will reveal light green leaves up to 4’ in length, with an off-center, silvery colored midrib (the primary leaf vein that runs from the base of the leaf to the tip) and serrated leaf edges. Underground, cogongrass exhibits a dense underground root system that can reach as deep as 4’. This feature is the primary reason cogongrass outcompetes other plants, withstands any drought, fire, or soil condition thrown at it, aids in its resistance to herbicide activity, and generally makes it very difficult to manage.
The first step in managing cogongrass is prevention. If your property or the property you manage doesn’t have cogongrass, do everything you can to keep it that way. While the species can spread distances through seed dispersal, it is much more frequently moved around by fragmented rhizomes hitching a ride on equipment. If you or a contractor you’ve hired are working in or around an area with cogongrass present, avoid disturbing it with equipment and be diligent in monitoring the site for outbreaks following the job’s completion.
If you find cogongrass on your property, effectively eradicating it requires patience, persistence, and several years’ worth of herbicide applications. Currently, of the hundreds of herbicides available for purchase, only two chemistries have been proven to be very effective in destroying cogongrass, impazapyr (Arsenal, Stalker, etc.) and glyphosate (Roundup, Cornerstone, etc.).
- Imazapyr is an extremely effective non-selective, residual herbicide that controls a wide variety of weed species, including cogongrass. Just one or two applications of imazapyr can provide 18-24 months of effective cogongrass control, with follow up treatments required as needed after that. However, Imazapyr has a major downside that limits its use in many settings. Because it is a non-selective herbicide with significant soil residual activity, it cannot be used around the root zones of desirable plants. Oaks, other hardwood trees, and most landscape plants are especially sensitive to imazapyr. This herbicide is best limited to use in fields, waste/fallow areas, natural areas, and monoculture pine plantations – it is not appropriate in most residential and commercial landscapes.
- The other option, glyphosate is a non-selective herbicide with no soil residual activity. It is often a better option where severe injury or death of desirable hardwood trees and ornamental plants cannot be tolerated. However, due to its lack of residual soil activity, glyphosate applications on cogongrass patches will need to be repeated on an annual or biannual basis for up to five years for eradication of the infestation.
*Regardless of which herbicide you choose, controlling cogongrass is a multi-year affair requiring diligence and patience.
For more information on cogongrass and for specific herbicide recommendations and application rates/timing for your site, please contact your local UF/IFAS County Extension Office.
by Larry Williams | Aug 26, 2021
Hot, summer months are not the time to be using most lawn herbicides.
One issue is the heat of summer. Most lawn herbicide labels include statements such as the following.
“Do not apply when temperature exceeds 90°F.” “Do not broadcast apply this product when air temperatures are above 90°F (85°F for St. Augustinegrass) unless temporary turf injury can be tolerated.”
Every year we’ll see lawns that are injured or killed because of lawn herbicides being applied when temperatures are too hot.
Summer is usually a rainy and windy time of the year. Many lawn herbicide labels include statements such as the following.
“Allow 12 hours after application before watering lawn for maximum effectives on listed weeds.” “Apply only when wind is no more than 10 mph.” “Applying this product in calm weather when rain is not predicted for the next 24 hours will help to ensure that wind or rain does not blow or wash pesticide off the treatment area.”
It is critical to read and follow the label directions and precautions for any pesticide you use. Pesticide labels, including herbicides, include the following statements.
“To the extent consistent with applicable law, the buyer assumes all risks of use, storage, or handling of this product not in accordance with label directions.” “It is a violation of Federal law to use this product in a manner inconsistent with its labeling.”
Crabgrass growing in centipedegrass lawn. Photo credit: UF/IFAS Extension
By the time summer arrives, many of the lawn weeds are mature, which means they are well established with extensive root systems. These mature, well established weeds are much more difficult to control. They are more susceptible to herbicides when they are small, young, and not well established. Also, these mature weeds have been allowed to produce countless numbers of seeds as they move into summer. Most weeds are prolific seed producers. For example, a single crabgrass plant (a common summer lawn weed) can produce 150,000 seeds.
Applying a preemergence lawn herbicide in February to help prevent summer annual weeds such as crabgrass or applying a postemergence lawn herbicide during spring while the weather is mild and before the weeds are out of control simply makes more sense than waiting until summer.
The best options now with lawn weed control involve continuing to follow good mowing practices, maybe hand removal of some weeds, and just simply waiting it out until next February and spring to worry with the use of lawn herbicides.
In the meantime, you may want to read the following UF/IFAS Extension publication on lawn weed control.
https://edis.ifas.ufl.edu/pdf/EP/EP14100.pdf
Larry Williams, UF/IFAS
by Pat Williams | Aug 11, 2021
The lawn is a source of pride for most and anything out of the ordinary causes alarm. Now image finding something that looks like lumpy green jelly in your turfgrass and it doesn’t go away. You try raking it, spraying it, covering it, and it still comes back time and time again. One of the things we see in late spring/early summer turf is a reemergence of cyanobacteria (Nostoc), sometimes confused with algae because of green coloring and this remains all summer long.
Dehydrated cyanobacteria in a centipedegrass lawn.
Unlike normal bacteria that needs a food source, cyanobacteria contains chlorophyll and produces its own food source through photosynthesis which allows it to grow on bare sandy soils, fabric mats, concrete sidewalks, plastic, and yes even your lawn. Besides the green pigment, it also produces a blue pigment and is why we call it cyanobacteria which means blue-green bacteria. In addition to photosynthesis, cyanobacteria can also fix nitrogen, and are believed to produce cyanotoxins and allelopathic compounds which can affect plant growth around them.
Cyanobacteria are considered one of earth’s oldest organism and they have tremendous survival capabilities. They can dry out completely, be flat, flaky, black-green dried particles in your lawn and once rehydrated, spring back to life. If you happen to notice it spreading throughout your yard, remember that pieces of the organism can stick to your wet shoes or lawnmower tires and be transported unintentionally.
The question then becomes how to control the cyanobacteria and reclaim your turfgrass. The first solution is to have a healthy lawn. Cyanobacteria likes poorly-drained compacted soils. This same condition is unfavorable to turf growth and why you end up with bare spots and establishment. Reduce soil compaction by using a core aerator, and then adding organic matter. This will increase drainage, gas exchange, and encourage microorganism populations which I like to call soil pets. Spike aerators only push the soil particles aside and don’t really loosen as well. Try to reduce low lying areas in the lawn where water sits after rainfall and irrigation. You might have to till and reestablish those areas of the yard.
The same cyanobacteria pictured above 24 hours after being rehydrated in a petri dish of standing water.
Controlling the amount of water Mother Nature gives us and humidity levels during summer is not possible, but you can control your irrigation whether it be automatic (sprinkler system) or hand-watered. During the rainy season, you should be able to get by with only rainfall and shut off your system. If needed during extended dry weeks, it is easy enough to turn the system back on. It is thought that cyanobacteria likes phosphorus which is another reason to use little to no phosphorus in your lawn fertilizers.
As you begin to rid your lawn of cyanobacteria, remember when fully hydrated it forms a slippery surface so be careful walking on it. Cultural practices will be more effective in controlling the spread versus using chemical methods. Cultural solutions are safer for your lawn, yard and all of the wildlife that visits. If you need help with your cyanobacteria, please contact your local Extension office and we are always happy to assist.
A special thanks to Dr. Bryan Unruh, UF/IFAS for his assistance in identifying the cyanobacteria.
For additional information, please read the sources listed below.
Biology and Management of Nostoc (Cyanobacteria) in Nurseries and Greenhouses. H. Dail Laughinghouse IV, David E. Berthold, Chris Marble, and Debalina Saha
Rain, Overwatering Can Cause Slippery Algae to Pop Up in Turfgrass. C. Waltz
Nostoc. N.J. Franklin
by Pat Williams | Jul 1, 2021
We work very hard to maintain our gardens and then we look up and vines are growing 20′ into the trees. I get asked frequently “what is growing up my trees?” My first answer is “probably the same things growing on your fences.” These include Smilax species, commonly called catbrier or greenbrier, Vitis rotundifolia, referred to as wild muscadine grape, Parthenocissus quinquefolia or Virginia Creeper, and the one to be most careful with, Toxicodendron radicans, known by many as Poison Ivy.
Spring growth on the Smilax vine.
Smilax is a native vine that grows quickly in spring and all summer. There are 12 species in Florida and 9 species commonly found in the Panhandle. Besides being armed with thorns on their stems and some leaves, Smilax spreads by underground stems called rhizomes. If you choose to ignore it, some species can cover your trees and the stems become woody and hard to remove. This vine also produces fruit and seeds are dispersed by birds all while the underground rhizomes are spreading under your lawns and gardens.
Smilax can quickly cover a tree trunk.
Removal can be difficult and mowing the vines only encourages more growth. When trying to remove by hand, wear heavy leather gloves and some eye protection because of the thorns. Cut the stems about three feet above the ground which allows you some stem to pull on to bring it out of your tree. You also then have a handle to pull and try to remove some of the rhizome from underground. Digging rhizomes is time consuming, but gives you piece of mind that they won’t come back immediately. Our family actually harvests the new shoots in spring and we use them like asparagus.
Wild muscadine grape is also native and difficult to remove. Most of the vines in nature are male and only produce by runners along the ground and then grow upwards. The female vine can produce 4-10 grapes in a cluster and then reseeds itself.
Wild muscadine grape covering a fence.
Wild grape completely covers plants and eventually the plants underneath can die. There are no thorns to contend with when removing wild grape, it is just time consuming, especially if it has taken over your fence or natural areas.
Virginia Creeper is a native vine, still considered a nursery plant in some areas of the country, and has bright red fall color.
Virginia Creeper climbing a tree trunk.
It is most often confused with poison ivy because of having five leaflets per leaf whereas poison ivy only has three leaflets per leaf. It spreads by seeds, runs along the ground, and is the easiest of these four vines to remove from your property.
Poison Ivy is a native vine distinguished by its three leaflets with the individual leaflets getting up to 6″ long. This vine spreads by seeds and underground rhizomes. What makes removal of this vine difficult is the urushiol oils which causes the skin rashes and blistering.
Poison ivy covering a tree trunk.
Care must be taken to cover up all skin and I recommend wearing waterproof clothes versus cotton which can absorb the oils and transfer them to your skin. Under no circumstances should these vines be put on the burn pile, the oils can become airborne and then you can inhale them.
Here are a few helpful tips when battling these native vines. First have patience and be dedicated, this removal will not happen over night. It may take a year or two to rid your property of the original vines. Be diligent though, because birds will continually land in your trees and deposit more seeds to get a fresh start. Try to remove vines when they are young and just beginning to climb your trees and fences. If you know you don’t have the time or energy to remove the vines from all your trees, at least cut the vines close to the ground to reduce flowering and new seeds. Be careful with poison ivy because falling leaves still contain oils. Once the vines start to have a new flush of growth, spray a non-selective herbicide on new growth and you should have good results. Lastly, remember one person can make a difference in trying to reduce the number of nuisance vines in our communities.
Here are some sited references to help with your removal tasks. Key to Nine Common Smilax Species of Florida. https://edis.ifas.ufl.edu/publication/fr375. Smilax is a Vine that can be Difficult to Control. http://blogs.ifas.ufl.edu/wakullaco/2017/04/21/smilax-is-a-vine-that-can-be-difficult-to-control/. The Muscadine Grape (Vitus rotundifolia Michx.) https://edis.ifas.ufl.edu/publication/hs100. Muscadine Grape Vines: Difficult to Control in Your Landscape. http://blogs.ifas.ufl.edu/wakullaco/2017/03/24/muscadine-grape-vines-difficult-to-control-in-your-landscape/. Parthenocissus quinquefolia: Virginia Creeper https://edis.ifas.ufl.edu/publication/fp454. Identification of Poison Ivy, Poison Oak, Poison Sumac, and Poisonwood. https://edis.ifas.ufl.edu/publication/EP220.
by Sheila Dunning | Apr 1, 2021
Call 811 before you dig. No one wants a weekend project to be the cause of internet, phone and cable outages. Worse yet, what if someone gets hurt from contact with natural gas or electrical lines? That’s why it is so important to have buried utilities in the yard located and marked before digging. Sunshine 811 coordinates each individual company to clearly mark where the service lines are located. Homeowners are required by law to contact 811 three days before any soil removal is done. The service is free.
Have information prepared before making the request. Describe the work to be performed (e.g. fence install, landscaping, irrigation install), including the type of equipment that will be used. Specify the exact location on the property and how long the work will continue. Finally, provide all the contact information (e.g. name, phone number, e-mail), should there be any additional questions.
Call 811 or request a single address ticket online. Receive a ticket number and wait two full business days, not counting weekends or holidays. Then contact 811 again. Make sure that all the utilities have responded in the Positive Response System (PRS). Sometimes that may mean that the company doesn’t have anything to make in the area.
If there are utility lines running through the yard, they will be marked with specifically colored paints or flags. Red is used for electrical lines, orange indicates communication lines, yellow means gas, blue is used for potable water, purple is reclaimed water, and green indicates sewer lines. White lines may be used to outline digging areas and pink are temporary survey marks. This is the APWA Uniform Color Code.
Every effort is made to locate the lines as accurately as possible. But, the safest thing to do is hand dig to expose the utility line before using any mechanized equipment. Lines can vary up to 24” from the marked line and depths can be less than 5”. Remember there may be access lines running through the property even if that service isn’t utilized at that address.
Keep safe this spring. Call 811 before digging.
by Larry Williams | Mar 25, 2021
As a boy in a small town in Georgia we had a St. Augustinegrass lawn. My dad started the lawn before I was born. That lawn was still doing fine when I left for college at age seventeen. I don’t remember weeds in the lawn during summer months. I do fondly remember winter “weeds” in that lawn.
To see clumps of winter annuals in our yard and in neighbors’ yards was a natural part of the transition from winter to spring. They added interest to what
Blue Easter egg hidden in chickweed. Photo credit: Larry Williams
would have been a plain palette of green. It was expected to see henbit with its square stiff stems holding up a display of small pinkish purple flowers in late winter and early spring. A clump of henbit was a great place to hide an Easter egg, especially a pink or purple one.
Wild geranium, another common winter annual, offered another good hiding place for Easter eggs with its pink to purple flowers. Large clumps of annual chickweed would nicely hide whole eggs. Green colored eggs would blend with chickweed’s green leaves.
Pink Easter egg hidden in crimson clover & hop clover mix. Photo credit: Larry Williams
Crimson clover with its reddish flowers, hop clover and black medic with their bright yellow flowers were good hiding places for Easter eggs. Plus clovers add nitrogen back to our soils.
I never remember my dad using any weed killer, he rarely watered. The lawn was healthy and thick enough to be a deterrent to summer weeds. But during fall and winter as the lawn would naturally thin and go dormant, winter annual weeds would run their course.
I’ve heard that the sense of smell provides our strongest memories. I remember the first mowing of the season with the clean smell of chlorophyll in the spring air. It was refreshing. Once mowed and as the heat took its toll, by late April or mid-May, these winter annual weeds were gone. What was left was a green lawn to help cool the landscape as the weather warmed. The lawn was mowed high as St. Augustine should be, played on and typically not worried with.
Most people have winter weeds in their lawns that let us know spring is near. Perhaps we worry too much with these seasonal, temporary plants that may have wrongly been labeled as weeds. Besides, how long have we been doing battle with these weeds and they are still here. Most lawns have countless numbers of winter annual seeds awaiting the cooler temperatures and shorter days of early winter to begin yet another generation. By May they are gone.
