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!
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!
Crape Myrtle season is almost upon us. Soon, every roadside, landscape, and gas station parking lot in the deep south will be lit up in gaudy colors from white to hot pink to fire engine red. A well-placed Crape Myrtle (Lagerstroemia hybrids) can turn even the most boring landscape into a picturesque photo op once summer rolls around. These toughest of flowering trees also ask very little of gardeners to look their best, thriving in many varied settings with a wide range of care given to them. Despite their low-maintenance nature, I see all too many Crape Myrtles languishing in landscapes. While it is difficult to fail with Crape Myrtles, it is not impossible if you site and maintain the trees incorrectly. This summer, follow these three tips to get the most out of the best small tree a southern landscape can offer.
Properly sited, pruned, and maintained crape myrtle. Photo courtesy of Daniel Leonard.
- Do not murder your Crape Myrtles. For any reason. No other tree gets lopped off each year to a random height in the belief that it makes it prettier. While your “murdered” crape may indeed produce more flowers the following season, you are permanently damaging the tree, giving rot and decay a foothold, unnecessarily making the tree more susceptible to storm damage, and ultimately shortening the tree’s lifespan. The only pruning that should be done to the species is an occasional “limbing-up” to expose the gorgeous flaky bark underneath and to remove dead or dying branches.
- Don’t plant Crape Myrtles in shade. Crape Myrtles perform their best in 6+ hours of blistering full sun per day. Even light shade at various times during the day will greatly reduce flowering, cause the tree to appear thin, and force it to reach for the sun, creating a leggy look. There are many wonderful small landscape trees like Greybeard, Redbud, and Japanese Magnolia that make excellent Crape Myrtle alternatives in shady sites. If you can’t put a Crape in full sun, plant something else.
- Keep the area under the canopy free of turfgrass. Turf is a wonderful feature in lawns, just not directly under crape myrtles. Grass does an excellent job of scavenging nutrients and water that otherwise would benefit the crape myrtle above. Also, having grass inside the dripline forces homeowners and landscape professionals to cut the grass right up to the trunk. This often leads to soil compaction from heavy mower traffic and damage from lawnmower decks and string trimmers, which damages the thin Crape Myrtle bark and can even girdle and kill the tree. Either kill out the grass and weeds under the canopy with a nonselective herbicide like Glyphosate and then mulch or plant a shade loving groundcover like Asiatic Jasmine.
Crape Myrtle is one of the most rewarding plants Panhandle gardeners can grow as well as one of the easiest. By following just a few best practices, not overpruning, planting only in full sun and keeping the ground free of turfgrass under the canopy, pretty much every landscape can enjoy success with the species. For more information on growing Crape Myrtle and other gardening topics, reach out to your local UF/IFAS County Extension office! Happy Gardening!
With the traditional planting date of Good Friday behind us, the home tomato gardening season in the Panhandle is in full swing. While tomatoes are the most persnickety veggie we grow, there are several practices you can adopt to help you succeed: selecting an adapted variety; regularly scouting for insects and disease; and watering and fertilizing appropriately. However, the most overlooked practice for success gardeners can adopt is proper pruning.
‘Big Beef’ Tomato with lower leaves removed. This is an excellent disease reduction practice. Photo courtesy of Daniel Leonard.
Correct pruning does a couple of positive things for tomatoes. First, it reduces the incidence of disease by preventing leaf contact with the soil, opening the interior of the plant, and allowing better airflow. This is important as many plant pathogens reside in the soil and only need a splash of water to travel onto plant leaves. Also, densely foliaged plants trap warm, moist air in their canopies, creating a perfect environment for disease to flourish. Letting the plant canopy “breathe” through pruning prevents that negative environment from forming! Second, correct pruning of “suckers” (extra growth points that can develop into shoots) helps tomato plants develop optimum yield and fruit quality. By removing suckers, more water, nutrients, airflow, and light are directed to the main stems, where the majority of tomato fruit production occurs. Failing to remove suckers (especially on indeterminate varieties) can result in reduced yields, increased disease, and generally messy plants!
With the reasons for pruning tomatoes established, the next step is learning exactly what to prune and how to do it in a sanitary matter.
- Get rid of any foliage that could encounter the soil, generally all leaves occurring on the lower 12-16″ of the plant. All kinds of nasty tomato destroying diseases, like Early Blight and Bacterial Leaf Spot, reside in the soil and are just waiting to be splashed onto your plants – don’t let that happen.
- Determine how many primary shoots you want your plant to have. Leave enough lower suckers to achieve that number (generally just one, two, or three as more than 3 primary stems gets hard to manage), and prune or pinch out all the rest. To prevent stress from pruning, be diligent in removing suckers when they are still small, 2” or less.
- Always clean and disinfect your pruners before making a cut on a tomato plant. This is best accomplished by rinsing the blades with warm soapy water, drying, and following with by a quick alcohol spray. A 10% bleach solution will also work, but if not thoroughly rinsed after, bleach can corrode pruner blades and other working parts. If you make cuts on a plant that appears diseased, repeat the sanitizing process before you begin pruning another plant as “dirty” pruners are an easy way to spread pathogens in the garden.
Developing vegetative “sucker” that will need to be removed. Photo courtesy of Daniel Leonard.
While tomatoes are indeed a difficult vegetable to grow, learning to prune them correctly will greatly help to make this a successful season. If you just keep leaves off the ground, suckers pinched, and pruners cleaned, you’ll be well on your way to less disease, prettier plants, and more tomatoes to pick. For more information on growing tomatoes and any other horticultural topic, please contact your local UF/IFAS County Extension office. Happy Gardening!
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!