by Daniel J. Leonard | Jul 22, 2021
If you’ve taken care of your yard properly from spring green-up to now (mid-July), you might think you can comfortably coast into the cool temperatures of fall without any problems. You would be mostly right, save for one extraordinarily tough weed that waits until the depths of summer to rear its troublesome head: Doveweed (Murdania nudiflora).
Doveweed seedlings just emerged on July 9, 2021. Photo courtesy of Daniel Leonard.
Doveweed is an insidious invader of Panhandle lawns. In the Panhandle, Doveweed germinates (sprouts) long after most other summer annual weeds, from late May-June when soil temperatures reach ~70°F. This allows it to sneakily avoid spring pre-emergent herbicide applications and even early summer post-emergent applications that target common weeds like Florida Pusley, Spurge species, and others. Doveweed also looks an awful lot like many of our common lawn turfgrasses, especially Centipede and St. Augustine Grass. It possesses thick, shiny, grass-like foliage and even grows in a spreading, low to the ground fashion. This mimicry causes many homeowners to not realize there is a problem until it’s too late. Once Doveweed is mature and displaying its characteristic purple flowers, it is very difficult to control. Finally, Doveweed is extremely tough and aggressive, particularly thriving in moist areas of the lawn. In these areas, Doveweed can easily outcompete the desirable turfgrass and, without intervention by you, will soon have the whole lawn to itself.
Controlling Doveweed is no easy task and requires a combination of practices to keep it out of your lawn. The first line of defense against any weed, Doveweed included, is through proper cultural practices. In turfgrass lawns, this means ensuring that you mow your lawn regularly and at the proper height (2.5” or so for Centipedegrass), keeping the lawn irrigated during droughty periods, fertilizing based on a soil test, etc. Being diligent in the above tasks will go a long way to ensuring that your turfgrass is healthy and better able to ward off a Doveweed invasion. However, even when homeowners maintain their turf perfectly, chemical herbicides are usually required to keep Doveweed at bay.
Doveweed patch in St. Augustine Sod.
While many commonly used homeowner herbicides are not effective on Doveweed, there are several quality options at your disposal.
- Doveweed is most easily controlled with preemergent herbicides, specifically one of the following: Atrazine, Pennant Magnum (S-metolachlor), Tower (dimethenamid), and Specticle (indaziflam). The issue with pre-emergents is that most folks shelve them after spring application in February or March. Since these products lose their efficacy after 4-6 weeks, Doveweed’s emergence in May is undeterred. To obtain control on Doveweed with these products, split the spring application and apply once in late Feb/early March and again in mid-late April.
- Doveweed can also be controlled by post-emergent herbicides after it is up and growing, though multiple applications may be required. The most effective formulations contain a combination of 2,4-D or Dicamba and other herbicides. While most of these products have at least fair efficacy on Doveweed, stronger, more expensive products like Celsius, Tribute Total and others provide better results.
- If Doveweed has already displaced turfgrass in large areas of your lawn, you may unfortunately be better off to make an application of a non-selective herbicide like glyphosate (Roundup), kill out the entire area of infestation and start over by resodding.
While Doveweed is a major problem in Panhandle lawns, it doesn’t have to be in yours! By keeping your turf healthy with proper cultural practices and making timely applications with effective herbicides, your lawn can be a Doveweed free zone! For assistance in Doveweed identification in your lawn, help choosing herbicides and calculating application rates, or any other horticultural information, contact us at the UF/IFAS Calhoun County Extension office! Happy Gardening!
by Stephen Greer | Jul 1, 2021
Photo Courtesy: Stephen Greer
Lawn areas come in all sizes and shapes. Some are large open expanses providing long views and others are smaller versions surrounded by shrubs and trees creating a more private and secluded setting. There are a number of reasons for reducing the size of a lawn with some coming into play with your decisions. A home lawn is often an important part of the landscape that provides a place to play outdoors from picnicking, tossing the ball to taking a quite stroll.
Maintaining a healthy lawn is important to an overall performance of this part of the landscape. Several factors are involved in the success in keeping a strong and resilient lawn. Understanding the needs of a grass to remain healthy involve soil testing to address soil pH and nutrient needs plus water challenges. Misuse of fertilizer and over irrigation can be costly to you and to the overall health of the lawn. These decisions can lead to reducing lawn size to managing cost or removing underused areas.
There are big benefits to reducing your lawn from saving time in mowing, trimming and other manicuring needs to saving energy costs involving the lawn mower not to mention reducing pollution from the mower or weed eater. The reduced amounts of pesticides needed to manage weeds and disease to the lawn saves time and money.
Another way to look at the reducing the size of our lawn is there will be more space for expanding plant beds and potential tree placement. These settings increase the opportunities for a more biodiverse landscape providing shelter, protection and food options for birds and other wildlife.
Photo Courtesy: Stephen Greer
The lawn can serve as a transition space that leads from one garden room space to another, while still offering a location to bring the lawn chair out to enjoy all that is around your lawn. Lawns and the landscape are ever changing spaces, especially as your trees and shrubs grow and mature to sizes that can directly impact the lawn performance. Often levels of shade will diminish edges and other areas of the lawn. This often will define the reduction of the lawn size moving going forward. Just remember that lawns and landscapes occupy a three-dimensional space involving the horizontal, vertical and overhead spaces. Just look around and think about what is best for you, your family and the setting.Are you more interested in developing other parts of the landscape? With many of us spending more time at home over the last year plus it gave time to think about the outdoor areas. Growing our own vegetables may be a new or expanding part of the landscape with the use of raised beds or interplanting into the existing landscape. Gardening can assist in reducing stress while at the same time providing that fresh tomato, lettuce, herbs and other fun healthy produce.
What ever your decisions are enjoy the lawn and landscape. For additional information, contact your local University of Florida IFAS Extension office located in your county.
by Daniel J. Leonard | Jun 24, 2021
Nutsedge, commonly called “nutgrass”, is one of the most important and difficult to control weed pests in the world. Found in nearly every growing situation, from crop fields and vegetable gardens to landscapes and turfgrass lawns, I bet every person reading this has contended with controlling nutsedge at some point! Nutsedge (a common term to describe several species of weeds in the genus Cyperus) not only reduces curb appeal, but also h as a detrimental effect on desirable plantings around it. Because of its aggressive nature and dense root system, it competes heavily with “good” plants for water, light, and nutrients, causing the plants we are trying to grow to suffer. This is a weed that you definitely do not want in your lawn or landscape!
To keep nutsedge at bay, it’s important to know a few facts about it. First, “nutgrass” is not a grass at all, but a totally different class of plants known as sedges. This is important because selective herbicides used to kill grassy weeds will not affect nutsedge. Though they’re grass look-alikes, sedges can be distinguished by their distinctive triangular shaped stems. You can actually feel the three edges of nutsedge stems. If ever in doubt over whether a weed is a grass or a sedge, remember “sedges have edges”. Most sedges are perennials, dying back to the ground each year in winter and reemerging from tubers, called “nutlets”, that can survive over a foot under the ground! Also, while sedges generally prefer wet areas, they aren’t very particular about where they grow and are equally at home in sand or clay, wet or dry, and sun or shade. All these characteristics make sedges hard to control and cause much consternation amongst gardeners!
The first line of defense in controlling nutsedge is keeping a dense cover over any bare ground. In lawns, this means maintaining a thick, healthy turf as weeds love to enter lawns through thin or patchy areas. This can be accomplished by mowing regularly, fertilizing appropriately based on a soil test, not overirrigating while also not allowing the grass to suffer badly during droughty periods. Easier said than done. In landscape beds, preventative control is a little easier. First, as nutsedge prefers wet areas, only irrigate when it is needed. During much of the year, most established landscapes can get by on rainfall alone. Next, simply maintain a roughly 3” layer of pine straw, wood chips, pine bark, or other natural mulch of your choice. Doing so will reduce all manner of weeds, nutsedge included, and is generally beneficial for ornamental plants as well! I do not recommend landscape fabric as it is a pain to install and remove and is not extremely effective at reducing nutsedge as the sedge’s sharp growing points punch right through most plastic or fabric mulches.
Though mulching and other preventative measures can reduce nutsedge numbers, those methods alone are usually not enough and chemical herbicides are required. Fortunately, in Panhandle lawns and landscapes, there are several excellent, readily available options for sedge control: imazaquin and halosulfuron.
- Imazaquin is the active ingredient in the common product Image Kills Nutsedge and has good activity on most sedge species. It can be applied safely to all the common turfgrass species grown in the area and can even be sprayed right over the top of most common ornamental landscape plants!
- Halosulfuron is the active ingredient in the product Sedgehammer (available online or at specialty landscape supply stores) and several other generic products. Halosulfuron products provide excellent control of all nutsedge species and are safe to use in all turfgrass species found in Florida. While most landscape plants are tolerant of halosulfuron application, use care and try to only spray it on sedge weeds to avoid any unwanted yellowing or damage.
While both products begin working immediately, it may take several weeks to see sedge weeds start suffering and patience is necessary! Though both products are effective, follow up applications 3-4 weeks later are generally necessary to clean up any surviving sedge.
Nutsedge is a nasty little weed that can be difficult, though not impossible to manage. Through some smart cultural practices and timely applications of either imazaquin or halosulfuron, you can keep your lawn and landscapes nutsedge free! For more information about nutsedge control on your property or any other agricultural or horticultural topic, contact your local UF/IFAS County Extension office! Happy Gardening!
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.
