by Larry Williams | Jun 10, 2021
Every time we have a dry period in spring or summer, I get those predictable calls about some mysterious pest that’s playing havoc in lawns.
Dry spots in lawn. Photo credit: Larry Williams
Without realizing it, the caller usually describes a textbook example of dry spots in a lawn. And many times that’s what the problem areas are – dry spots.
Dry spots are the result of imperfections in an irrigation system. They are revealed during dry weather. Adequate rainfall masks the imperfections in an irrigation system.
Possible imperfections are many. The homeowner may easily fix some irrigation system problems while other problems may require the expertise of a licensed irrigation contractor. There may be too few sprinkler heads for adequate coverage, insufficient pressure to operate each zone, incorrect choice of nozzles or wrongly mixing rotors with spray heads on the same zone. The cause for dry spots may be as simple as a maladjusted spray head, a broken spray head, a plugged nozzle, a tree or shrub blocking the water, grass that has grown over a pop-up spray head, etc.
Regardless of the cause, there are a couple of simple tests that can help confirm that the problem areas are to be blamed on lack of sufficient water vs. a mysterious pest.
First, check the affected areas by taking a soil sample in the root zone. Use a soil probe or shovel to remove a core of soil to a depth of 6 to 8 inches. Visually inspect and feel the soil sample for moisture. Do the same test in an area of the lawn that looks normal and compare the difference. It should be obvious if there is a difference in moisture between the areas tested.
The second test involves placing several empty straight-sided cans such as tuna fish cans in the affected area and several in a “normal” area of the lawn. Then let the irrigation system run long enough to collect some water in the cans. Compare the amount of water collected in the two areas. It should be obvious if there is a difference in the amount of water applied in the areas tested.
These tests are cheaper, less trouble and more environmentally friendly as compared to purchasing and applying pesticides for nonexistent pests as a result of incorrectly diagnosing the problem. If these tests do not identify the problem as lack of water, you may have a lawn pest. But don’t guess.
Occasionally inspect your irrigation system while it’s running for obvious, easily corrected problems such as a maladjusted or broken spray head. The following UF/IFAS Extension publications will help with your inspection. https://edis.ifas.ufl.edu/entity/topic/residential_sprinkler_systems
by Larry Williams | Apr 29, 2021
I’ll be the first to admit that North Florida lawns are frustrating. With time, most people discover this.
Why are lawns so difficult here? The answer involves a combination of factors.
We are not far enough north to benefit from the better soils. Florida is known for sandy, low fertility, low water holding capacity soils. Some areas of the country enjoy richer soils with better water and nutrient holding capacities. These better soils result in a more favorable lawn root environment with roots being more competitive and resilient.
Something else happens in more northern areas. The heavier soils and colder temperatures (sometimes resulting in the soil freezing) are natural means of inhibiting and/or controlling certain soil dwelling pests. For example, nematodes are not nearly the concern in northern lawns. Many people that move to our area have never heard of these microscopic roundworms that play havoc in our low fertility, warm, sandy soils. After a lawn has been in place for a number of years, allowing the nematode population to reach a threshold, the lawn begins to decline. And we have few legal, effective chemical control options for nematodes in Florida lawns.
Declining area in lawn due to ground pearl. Photo credit: Larry Williams
Some other soil dwelling pests that northerners don’t have to deal with include ground pearls, small scale-like insects that bother centipedegrass roots. Mole crickets are not a pest much north of Central Alabama. Years ago, a representative with the company that manufactured the once popular mole cricket insecticide Oftanol told me that in the absence of the state of Florida, they would not sell enough Oftanol to keep it on the market. Take-all Root Rot, a common soil dwelling fungus, plays havoc in our Florida lawns and it is difficult to control.
We are not far enough north to use the more trouble-free northern grasses to create a permanent lawn. These include bluegrasses, fescues and perennial ryegrass. At best, these grasses can be used to overseed our lawns during the cooler fall and winter months to create a temporary winter lawn. But they will not survive our hot, wet summers.
We are not far enough south to benefit from the lack of freezing temperatures during winter. A late freeze that occurred on April 8 a number of years ago resulted in much lawn injury. I saw lawns with seventy percent kill from this late freeze. This is something that typically does not happen in Central and South Florida.
We deal with saltwater issues, high humidity, hurricanes and tropical storms, an array of lawn insects and diseases and extremes in rainfall and temperatures.
It’s no wonder most people become dissatisfied with their lawns. Perhaps we should lower our expectations and enjoy the natural flora and fauna of our state.
by Daniel J. Leonard | Apr 8, 2021
The line separating what is a weed and what isn’t often comes down to where the “weed” is growing and who is managing the area it’s growing in. Blue Eyed Grass (Sisyrinchium rosulatum), one of the most complained about lawn weeds this winter/spring falls squarely in that category! Native plant enthusiasts and homeowners looking to add native wildflowers to their landscape value the plant for its low maintenance, star-shaped blue blossoms in spring. Professional and home turfgrass managers, however, loathe the plant as it masquerades as grass to the untrained eye, looks messy in the cool months, and can displace turf during spring green up. While Blue Eyed Grass can be a pretty landscape plant, our focus today is on learning why it is such an annoying weed in turfgrass areas and exploring control options if it becomes a problem!
Blue Eyed Grass (Sisyrinchium rosulatum) in a Centipedegrass lawn in late March. Photo courtesy of Daniel Leonard.
For starters, Blue Eyed Grass (BEG) is not even a grass, though it does look an awful lot like one! It is actually a member of the Iris family and is more closely related to spring beauties like Gladiolus, Iris, and Crocus than any turfgrasses. The flowers, appearing late March through April, are a dead giveaway that we aren’t dealing with a grass, as are the flat leaves arranged in bunched fan-shaped rosettes. BEG is considered a winter annual plant in Florida, meaning it sprouts from seed in the fall, grows through the winter, then flowers and sets seed in the spring. Because it grows while lawn grass is dormant, it is very noticeable during its entire lifespan. Though BEG can tolerate a range of soil types, it prefers to grow in moist areas, making it right at home in Panhandle lawns and landscapes in the winter as we experience regular to excessive rainfall throughout our cool season.
All the above characteristics make BEG an annoying weed in lawns. It hides in turfgrass very well until the turf goes dormant in the dead of winter, leading most homeowners to ignore it until it becomes a problem in the spring. At this point, BEG is nearing maturity and is more difficult to control without damaging the turfgrass. BEG also thrives in our climate and can outcompete poorly managed turfgrass, especially if the lawn exhibits the soggy, compacted conditions that heavy lawn foot traffic and winter/spring rainfall cause. So, what is a homeowner to do?
The first step in controlling BEG is maintaining a healthy turf. Ensure you’re treating your turf well during the growing season by fertilizing appropriately, mowing frequently at the correct height, and irrigating properly. Sending turf into the dormant season stressed by poor growing season management is an invitation to winter weeds. Other cultural practices that can help mitigate troublesome winter weeds like BEG are periodic mowing during the cool season to prevent weeds from going to seed and being diligent about not frequently driving on, parking cars on, or otherwise excessively compacting the soil, a common cause of unhealthy turfgrass.
Blue Eyed Grass clump brought into the Calhoun County Extension office for identification and control recommendations in February 2021. Photo courtesy of Daniel Leonard.
After implementing the above cultural practices in your lawn management regime, you may also need chemical herbicides to achieve a clean cool season lawn. There are two basic options for BEG control. First, a fall (mid-late October) application of a pre-emergent herbicide like dithiopyr, prodiamine, or pendimethalin can be very effective at preventing winter weeds from occurring at all. If you happen to miss this fall pre-emergent application, a timely post-emergent application of 2,4-D or other general broadleaf herbicides works nicely as well. (BEG and other cool season weeds are best controlled with post-emergent herbicides in December and January before they mature and begin to set seed. Plan applications accordingly!)
While Blue Eyed Grass can be an attractive addition to the landscape, it is never welcome in turfgrass! To prevent this and weeds from becoming a problem, use smart cultural practices to maintain a healthy turf and make timely herbicide applications when needed. For more information on controlling Blue Eyed Grass and other winter weeds, contact your local UF/IFAS Extension office!
by Pat Williams | Mar 11, 2021
Our trees and vines are flowering and lawns are starting to green up naturally, but one glance at the calendar and it is still early spring. The last official frost date for the Florida panhandle can be into April depending on location. We know our day time and night time temperatures are still fluctuating every other day. We also know the stores and nurseries are stocked with shelves and pallets of fertilizer. So the big question is when can I fertilizer my lawn?
Overseeded ryegrass on a centipedegrass lawn.
My answer after years of practice is always it depends, but my non-scientific rule of thumb to homeowners is wait until you mow three weeks in a row and make sure you’re past the last frost dates for your area. If you need to mow three weeks in a row for height, then your lawn is actively growing and most likely we are into a temperature range good for fertilizer applications. If you apply fertilizer to a lawn that is dormant, the fertilizer will not be taken up by your roots and it can leach below the root zone wasting money while not improving the lawn and possibly causing environmental concerns.
With that said, there are some factors to consider. We always recommend doing a soil test first. This can be done in advance of spring. Your test results might indicate having sufficient nutrients in the soil, so not applying would save you money and the lawn would still look good. The soil test will also indicate what nutrients are in excess or lacking, then you can apply only the nutrients needed.
I have found that fertilizer is still very much misunderstood. When I ask homeowners whether they consider fertilizer to be medicine or a stressor, most will answer medicine and we all know if a little medicine is good, then a bit more is better. However, it is more accurate to think of fertilizer as a chemical stressor. If my lawn is unhealthy, then I force my lawn to grow and it can further weaken my plants. Think of it like this, if you’re not feeling well at night before you go to bed, should you consume one of those big energy drinks? Not if you want to sleep and hopefully feel better in the morning. Apply fertilizer when the lawn is ready and capable of having a positive response when spring fully arrives.
Wakulla County Extension office mixed species turf.
Here are some items you should know before you fertilize the lawn. Fertilizers used in Florida should have a license number that begins with F followed by a series of numbers. It is important to check your fertilizers before you apply. You need to know what type of turfgrass you have in your lawn. We have a lot of bahiagrass and centipedegrass lawns in the panhandle. Each will require a different regiment. You are only allowed to apply one pound of nitrogen per 1,000 square feet per application and you should never apply more than the recommended rate. I always refer to a childhood fable “The Tortoise and the Hare” when thinking about plant health. Slow and steady makes for a better lawn in the long run. This means you need to measure your lawn, understand how to calculate the nitrogen and then apply correctly with the right equipment and spreader patterns. We also recommend very little phosphorus (the middle number on the fertilizer bag 15-0-15) for Florida lawns. Our soils are usually sufficient and this is another item your soil test results will confirm.
Remember, your local Extension office is always here to help especially making sure you treat the lawn right. Think before you apply because your long-term goal is improving the lawn quality.
The Florida Fertilizer Label (https://edis.ifas.ufl.edu/ss170) and General Recommendations for Fertilization of Turfgrasses on Florida Soils (https://edis.ifas.ufl.edu/lh014). T. W. Shaddox, assistant professor; UF/IFAS Fort Lauderdale Research and Education Center, Ft. Lauderdale, FL 33314
Homeowner Best Management Practices for the Home Lawn (https://edis.ifas.ufl.edu/ep236). Laurie E. Trenholm, professor, Extension turfgrass specialist, Environmental Horticulture Department; UF/IFAS Extension, Gainesville, FL 32611.
Bahiagrass for Florida Lawns (https://edis.ifas.ufl.edu/lh006). L. E. Trenholm, professor, turfgrass specialist, Department of Environmental Horticulture; J. B. Unruh, professor, turfgrass specialist, UF/IFAS West Florida Research and Education Center; and J. L. Cisar, retired professor, turfgrass specialist, UF/IFAS Ft. Lauderdale REC; UF/IFAS Extension, Gainesville, FL 32611.
Centipedegrass for Florida Lawns (https://edis.ifas.ufl.edu/lh009). J. B. Unruh, professor, turfgrass specialist, UF/IFAS West Florida Research and Education Center; L. E. Trenholm, associate professor, turfgrass specialist, Environmental Horticulture Department; and J. L. Cisar, professor, turfgrass specialist, UF/IFAS Ft. Lauderdale REC; UF/IFAS Extension, Gainesville, FL 32611.
by Evan Anderson | Sep 14, 2020
Florida pusley has a low, spreading habit.
Florida pusley and its relatives, Brazilian and large-flower pusley, are common sights in lawns and landscapes during the summer. These prolific and tenacious weeds are closely related species in the genus Richardia, in the Rubiaceae family which includes coffee, bedstraw, and the plant from which the emetic ipecac is derived. With their thick leaves, low and spreading growing habit, and bright white flowers, they can quickly take over bare spots in a lawn and become quite a nuisance.
Because bare spots are a magnet for pusley (and weeds in general), one method to help prevent this weed from becoming a problem is to ensure the turfgrass is as healthy as possible. Well established grass can outcompete many other competitors. Keeping a lawn in tip-top shape includes watering properly, mowing at the recommended height for the grass species and variety, fertilizing appropriately, and controlling pests and diseases in a timely fashion. This can take some work in North Florida’s hot, humid climate, but prevention is almost always easier than trying to cure a problem.
Florida pusley is quickly noticed as soon as it flowers. While some may find the flowers attractive, they set seeds swiftly and before you know it, the next generation of plants is ready to go. Surprisingly, they are also an important nectar plant for honeybees. If chemical control is warranted for an infestation, a pre-emergent herbicide may help. Timing is important for this, so keep an eye on the thermometer – pre-emergents should be applied in the spring (February or March) when temperatures reach 65-70 degrees Fahrenheit for four to five days in a row. Examples are products with active ingredients such as atrazine or pendimethalin, though atrazine should not be used on bermudagrass or bahiagrass.
For weed problems that are already established, there are post-emergent herbicides available. In bahia, bermuda, and zoysia, products containing 2,4-D (or mixtures, such as 2,4-D and dicamba) can work fairly well. These products may require two applications to adequately control pusley. Be aware that some herbicides are sold under trade names that may be confusing, such as Roundup for Southern Lawns, which is a mixture of 2,4-D and penoxsulam, and is labeled for use on bahia, bermuda, St. Augustine, and zoysia grasses . It does not contain glyphosate, and Roundup that DOES contain glyphosate will kill turfgrass as well as weeds. Check the active ingredients on the herbicide label.
In St. Augustine lawns, options are more limited. Homeowners with St. Augustine may want to consider contacting a lawn care company for help with pusley. The available herbicides that are labeled for use in this instance are either difficult to use or prohibitively expensive (The herbicide Celsius, for example, costs over $100 per 10 oz. bottle). Another chemical that is effective is metsulfuron, and while it can be used in bermuda and zoysia lawns as well, it comes with some serious difficulties. First and foremost, it can be taken up by the roots of plants and is NOT safe to use around trees or shrubs. Properly measuring the chemical is tricky, as it may take only a single ounce to treat a whole acre. Serious damage can be done to surrounding plants if it is mixed or used improperly, and as such it may be difficult to find at local stores.
Homeowners who choose an herbicide to control pusley or any weed should be aware that high temperatures during the Florida summer can cause chemicals to affect the grass as well. St. Augustine is especially prone to this, and some herbicides such as 2,4-D may affect grasses more when temperatures rise above 85-90 degrees Fahrenheit.
A closeup of Florida pusley flowers.
Treatment of pusley and weeds in general is most effective when the plants are young. Large pusley plants have deeper roots and may take more applications of herbicides to control effectively. Furthermore, of the pusley species that can be found in our area, large-flower pusley is more difficult to control and may be tolerant of some chemicals. For more information, contact your local Extension office.
-Evan Anderson, Walton County Horticulture Agent
