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.
Larry Williams, UF/IFAS
Nearly everyone likes turfgrass lawns. They’re pretty and green. They filter water, chemicals, and nutrients before they enter our groundwater systems. They provide a recreation spot for people and pets. But lawns also come with maintenance tasks, one of which is weed control. Fortunately, keeping our common Centipedegrass lawns relatively weed free is as simple as smart management and utilizing herbicides effectively. Though the number of herbicides available for purchase can be overwhelming, you only need three to keep weeds at bay – a selective grass herbicide, a strong broadleaf herbicide, and a sedge herbicide!
Dollarweed, one of the toughest broadleaf weeds for homeowners to control. Picture courtesy of Julie McConnell, UF/IFAS.
First up on the essential herbicide list is the selective grass herbicide Sethoxydim. While most folks’ weed focus is centered on broadleaf weeds, grassy weeds like Crabgrass, Bahiagrass, Goosegrass, and others can be just as problematic and make for a very unsightly lawn. Enter Sethoxydim. Cheap and easy to find, Sethoxydim is offered as the active ingredient in many branded products like Fertilome Over the Top Grass Killer, Hi-Yield Grass Killer, and many more. These products control weedy grass species without seriously harming Centipedegrass or broadleaf ornamental trees and shrubs (Centipedegrass may temporarily be yellowed after sethoxydim application but will recover). Not only will it kill out the unwanted grass growing in your Centipede, but it will also remove these weeds from your flower beds!
Second, having a strong broadleaf herbicide on hand is necessary. I say “strong” because many of the homeowner grade products available at garden centers simply don’t have the “juice” to control tough broadleaf weeds like Dollarweed, Doveweed, Virginia Buttonweed, and others. For this job, I prefer to use a commercial grade 3-way product like Celsius WG by Bayer. Celsius WG is a 3-way combination herbicide with a healthy dose of Dicamba as its primary ingredient. Though Dicamba is a notoriously volatile chemical known to cause damage to unintended plants through drift in hot weather, combining it with the two other products in Celsius WG makes it safe to use in lawns, even in the heat of summer. While strong broadleaf herbicides like Celsius WG are expensive on the front end, don’t let that deter you. These products wind up being very cost effective in the long run due to minute mixing rates (one bottle goes a very long way in most residential lawns) and effectiveness – you simply will not need to waste time and money spraying lawn weeds over and over to obtain control like is necessary with lesser products – one or two applications will solve the toughest broadleaf weed problems.
Finally, any good lawn weed control program will include a quality sedge control herbicide. Sedges (often called “nutgrass”) look like grasses but are a completely different category of plants and as such, require specialized herbicide chemistries to achieve control. Sedge weeds prefer wetter areas of lawns, though they can occur in pretty much any lawn site and are very unsightly. For this weed category, there are several options available to homeowners. The one that consistently provides the best control in lawns is Halosulfuron-methyl, the active ingredient in the aptly named product Sedgehammer. Conveniently coming in individually pre-mixed packets for small lawns or a larger bottle when more acreage is to be treated, Sedgehammer couldn’t be easier to mix and use. While Sedgehammer and similar products are extremely effective in controlling various sedge weeds, they tend to work very slowly, and patience is required. Weeds immediately stop growing following a Sedgehammer application, but it can take up to three weeks to notice the sedges dying.
While having and using the above three herbicides can control almost any weed homeowners may encounter in their lawns, it is important to remember that herbicides are not substitutes for proper lawn management. When good cultural practices in lawns are followed, such as mowing at the correct height, only watering when necessary, following UF/IFAS fertilizer recommendations, etc., chemical weed control may not even be necessary in many cases! Also, once the decision to purchase and use chemical herbicides has been made, it is critical that one always read the label before using any herbicide product. This ensures safe and effective use of the product; the label is literally the law!
For assistance in choosing the correct herbicide for your lawn and other lawn care concerns, contact your local UF/IFAS Extension Office! Happy Gardening!
Native Gaillardia. Photo courtesy UF/IFAS.
The hottest days of the summer are here and you might be thinking, “There is no way something could survive this heat!”. You might also be wondering “What can I do in my landscape?” Well, you are correct – it is hot and there are not many plants that thrive in this type of weather, but the good news is we are at the end of the summer season and there are things we can begin to do to get ready for fall. It’s not too late to get the last of the summer vegetables going such as lima beans, cucumbers, eggplants, and peppers. Many cool season crops can also be planted by seed now and tomatoes will thrive going into the fall season. See Vegetable Gardening in Florida
There are some heat-tolerant annuals like vinca, gaillardia, bulbine, and coleus that can be planted now in the landscape. See Annuals. Any time of the year, even late summer, bulbs like Aztec Lily, Butterfly Lily, Walking Iris, and Spider Lily can be planted. See Bulbs for Florida. Not many herbs do well in our Florida sun this time of year, but Bay Laurel, Ginger, Mexican Tarragon, and Rosemary can be planted as transplants now but not as seeds just yet. See Herbs.
August and late summer is the time of year that you may be seeing damage in your lawns. This could be caused by insects, disease, or irrigation failure. It is important to determine the cause, so the proper remedy is used. Some ways to avoid lawn damage are checking your mower blades regularly and making sure they are sharp. Also only cut the top one third of the blade of grass to not stress it in the heat of the day. It is good practice to test your irrigation clock and have a rain sensor. Some municipalities in north Florida prohibit the application of fertilizer during the summer rainy season from June to September so check with your local extension office. See Insect Management in Your Florida Lawn
You can become more self-sufficient by growing your own healthy food in your backyard. Photo by Molly Jameson.
There are some other maintenance measures you can take in August to help your landscape and prepare for the fall season. If older palm fronds are yellowing, this could indicate a deficiency in magnesium or potassium. Talk to your local agent or visit your local store for an appropriate palm fertilizer. See Palm Nutrition and Fertilization. Are you holding on to those beautiful fall mums or decorative Christmas poinsettias? Now is the time to pinch them back to allow time for buds to set for winter blooms. Finally, it is a good time to deadhead (remove old blooms) and fertilize flowering annuals and perennials. We’ve had substantial rain this summer, so keep in mind that the soil could be lacking nutrients. A soil test can give you data that indicates what you need for the up-and-coming growing season.
Information for this article can be found in the UF/IFAS EDIS publication: “North Florida Gardening Calendar” by Sydney Park Brown: ENH1190/EP451: North Florida Gardening Calendar (ufl.edu)
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.
Two-Lined Spittlebug. Photo courtesy of Evan Anderson.
Problems with turfgrass come in all shapes and sizes. One that may affect your lawn is an insect that has two very distinct life stages. Named for the two distinct stripes on its back, the two-lined spittlebug looks like a plant or leafhopper during its adult life. When it is young, however, it is often camouflaged and not readily visible. The small green nymph hides in a mass of white froth or spittle that it secretes for protection.
The two-lined spittlebug is not a picky eater, though it cannot harm people or pets. It feeds on a variety of plants, piercing the stem or leaves with its mouthparts and sucking out the juices within. While it may not be picky, it does have favorites. Holly bushes are one food of choice for this pest and centipedegrass is another, so those growing this grass should keep an eye open. The protective spittle masses are usually close to the ground, so they may not be readily visible from above.
Centipedegrass displays feeding injury from spittlebugs in the form of purple or white striping along its leaf blades. If infestations are particularly heavy, the grass may turn yellow, then brown, and eventually curl up as the leaves die. Populations of the adults that cause most of this damage are typically largest in June, with another spike around August or September as the year’s second generation matures. Years with excess rainfall in spring and summer will see increased numbers of spittlebugs.
Spittlebug damage on Centipedegrass. Photo courtesy of Larry Williams, Okaloosa County Horticulture Agent.
If you are having a problem with these pests, make sure you are keeping your lawn as healthy as possible with good cultural practices. Proper watering, fertilization, and mowing to the appropriate height can all help to keep grass strong enough to withstand pests. Remove excess thatch, as it holds moisture and can favor the growth of spittlebugs.
Insecticides may be used to help with control as well. Options for Florida include pyrethroids such as bifenthrin, permethrin, and cyfluthrin. Products with the active ingredients imidacloprid and carbaryl are other options. Read the label of any product you choose. If you have questions or need help in identifying a pest problem in your lawn, contact your local Extension office.
Powderpuff mimosa (Mimosa strigillosa), also called Sunshine Mimosa or Sensitive Plant, is an increasingly popular native plant for home and commercial landscape applications that offers a very show display of puffy pink flowers this time of year!
Powderpuff Mimosa, (Mimosa strigillosa). Photo courtesy of Ray Bodrey.
This Florida native, low-growing groundcover grows no more than eight inches in height, and that would be classified as an extremely vigorous stand. Powderpuff Mimosa is technically a perennial legume, meaning it doesn’t need any nitrogen fertilizer from gardeners.
The groundcover is appealing to the eye with its dark green fern-like leaves. Not an evergreen, the plants fall into a semi-dormant to dormant state during the fall and winter seasons. Powderpuff Mimosa is a very resilient groundcover as well, needing little irrigation, spreading quickly, and co-existing well with turfgrass. Just a few pots of this species transplanted should cover up to 300 square feet in a season. Although it spreads quickly, it can easily be pruned or mowed if it moves into unwanted areas.
Powderpuff mimosa is a great plant for erosion control due to its deep roots. These deep roots also allow for good levels of drought tolerance. There are very few insect or disease problems with this plant, other than the occasional caterpillar. It is a very wildlife and pollinator friendly plant, with honeybees, butterflies, deer, and more all finding it appealing. It’s even considered a livestock forage, as cattle find it palatable.
Looking to plant powderpuff mimosa in your landscape? Any area that gets mostly full sun is just fine. This plant is adapted to a wide range of soils, but particularly flourishes in well-drained, sandy loam soils. Be sure to water regularly, especially to ensure successful establishment in your landscape. Find this wonderful little plant at Florida native plant nurseries!
For more information contact the Gulf County Extension Office at 639-3200 or email at email@example.com.
Supporting information for this article can be found in the UF/IFAS Extension website: https://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/powderpuff-mimosa.html & USDA website: https://plants.usda.gov/plantguide/pdf/pg_mist2.pdf
UF/IFAS Extension is an Equal Opportunity Institution.