Heather Kirk-Ballard, Polozola, Michael, Singh, Raghuwinder, Strahan, Ronald E., Hawkins, Keith, Shields, Sara Rogers, Fontenot, Kathryn, Fields, Jeb S.
2022 Summer Dean Lee
Virtual Field Tour
Our annual summer field tour videos will be released on our Dean Lee YouTube channel in August 2022.
Horticulture videos created by Central Region horticulture agents are available on our Dean Lee YouTube channel (https://bit.ly/DeanLeeYouTube) and Central Region horticulture webpage.
Greetings and welcome to the summer 2022 edition of the Central Region Horticulture Hints!
If you have not yet visited the native plant demonstration garden at the Dean Lee Research and Extension Center, I would highly recommend you visit this summer. We have several different phlox varieties planted, and they make a tremendous statement in the landscape every spring and summer. One of the plants I would like to call special attention to is the pink garden phlox, Phlox paniculata. This phlox variety produces large domed clusters full of bright purplish-pink blooms from late spring into early fall. Like many garden phlox varieties, these plants will grow 2.5 to 3.5 feet high and 2 to 3 feet wide. Pink garden phlox prefers mostly sunny light conditions, tolerates a small amount of shade and is winter hardy down to U.S. Department of Agriculture Hardiness Zone 4. Plants should be fertilized in late winter or early spring. To keep plants looking clean and to extend the flowering season, spent flowers should be removed. Cutting back last year’s stems in late winter will also keep the plants looking clean as they begin growing in the spring. Pink garden phlox should be grown in well-drained soil with adequate soil moisture, especially during dry spells. The height and visual impact of the plants can really make a statement in the landscape, so I encourage you to plan to add some to your garden this fall!
Please join us as we continue to expand and strengthen our horticulture efforts throughout the Central Region. If you have any questions on these initiatives, please contact your local LSU AgCenter extension office.
Sara Shields, Ph.D.
Louisiana Master Gardener State Coordinator
Central Region Horticulture Coordinator
In this article:
|Staying Cool in the Garden
|Managing Gophers in the Landscape
|Announcing the 2022 Louisiana Super Plant Inductions
|Checklist for June, July, August
|Bountiful Vegetable Gardening
|Tips for Summer Care of Turfgrass
|Leaf Spot and Fruit Rot of Strawberry
As summer temperatures rise and we seek ways to avoid the heat, let’s not forget about our plants. If it is so hot and oppressively humid outside that we are not comfortable, the same will be true for many of our plants.
In a way, plants can “sweat” through the process of transpiration to help them stay cool. As water evaporates through open stomata, some localized cooling effects can occur. Just like us, this process becomes less efficient at high humidity levels.
Make sure your plants stay hydrated and water them regularly to ensure that they can stay “cool.” You may have to water some plants more often than others depending on growing conditions and sunlight exposure. I have found that my pots in full sun will often need daily watering in the height of our summer. Those in the shade may only need weekly or biweekly watering under the same temperature conditions. Landscapes should not need intensive watering schedules to maintain, but they will likely benefit from intermittent irrigation.
There can be situations where plants have plenty of water in the soil but are wilted. This symptom being induced from water stress should be rare in our area. Conditions that favor it are dry with intense sunlight (light wind can influence as well) where evaporation through stomata occurs faster than stomata can replace lost water. More frequent causes of wilting with adequate water in our area are pathogen based. In those situations, there is often not much that can be done other than sourcing disease-resistant selections for the next planting.
Some of your potted plants might benefit from being moved to a shadier location in August and September. In some cases, you can even bring the protected location to them if you build a temporary shade structure over your growing space. And don’t forget to protect yourself when you are in the garden! Make sure you are staying hydrated and are protecting yourself from heat, humidity and intense sunlight.
A proper sun hat should be an essential part of any gardener’s kit. I may not look exceedingly handsome in my large floppy sun hat, but I still use it when I am outside for a significant amount of time. Protecting your face from sun is a critical step to prevent premature aging and, more importantly, cancer. This same principle applies to the rest of your body, as well. It may seem paradoxical, but if you are going to spend the whole day outside you may want long sleeves and pants as opposed to short ones. This is especially important to those that have a family history of skin cancers but should be considered even by those who do not.
Keep yourself watered! During the height of our humid summers, it can be extremely difficult to consume enough water to replace what we are losing. There are times I come back inside completely soaked after a short period and I know it will take me the rest of the day to rehydrated. If this is something that happens regularly you may want to consider electrolyte supplements. Sports drinks are a temporary solution, but if you work outside often, more effective electrolyte solutions will be needed.
Know your body and don’t push yourself too hard. Make sure you are familiar with symptoms of heat stroke. If you feel yourself becoming disoriented or suddenly chilled when you should be hot, immediately stop and go inside. From there, hydrate yourself and cool down while monitoring yourself to determine if further medical attention is necessary.
Michael Polozola, Ph.D.
Several species of gophers (Geomys species) can be found throughout Louisiana, although they are generally found in sandier soils and are not inclined to inhabit areas of soil made of dense clay. In general, the gophers are less likely to be in soil that has a high moisture content. They will dwell in burrows most of the year, except for periods of excessive rainfall.
Gophers are solitary animals that spend nearly 75% of their time in burrows, or nests, only coming out to find food and to mate (breeding season in Louisiana generally runs from February to August). There will only be one gopher in each burrow system, so even if there are four or more dirt mounds grouped within a few feet of each other in a line, all those belong to the same gopher.
So, what are the options for managing gophers? A wildlife biologist with the Louisiana Department of Wildlife and Fisheries shares some of the more cost-effective methods of gopher control. The first method is to flood the tunnels. The water fills the tunnel system, which causes the occupant to drown or flee to the surface, making it a target for predators in the area. Another method is fumigating with carbon monoxide. Carbon monoxide from automobile exhaust is more effective than other fumigants because of its greater volume and pressure, according to University of Nebraska-Lincoln.
A third option for controlling gophers would be to use a gopher trap. Instructional videos for properly setting traps are readily available online. Remember, gophers are solitary animals, so you will likely only successfully trap one gopher at a time. An online search for “gopher traps” yielded several brands and designs for this type of trapping device. One final option would be to use a bait. These gopher baits don’t usually post a huge risk to nontargets because they’re placed in the burrow and not easily accessed by other animals.
From the persistence of COVID-19 to record-breaking natural disasters, 2021 presented numerous challenges to us all. The green industry has experienced its share of unique problems, too, often making it difficult to find the exact cultivar to stock in the nursery or plant in the landscape. With this in mind, we are hoping to make Louisiana Super Plant access a bit easier with the 2022 selections, all of which provide a bit of flexibility in this ever-changing time. This doesn’t mean the superiority of the plant material is compromised, though! Each of the 2022 Louisiana Super Plants has been rigorously tested and vetted by the LSU AgCenter and members of the industry to be a perfect fit for every Louisiana landscape!
Spring 2021 proudly welcomed the addition of Louisiana iris to the Super Plants program. Native plants, such as the Louisiana iris, are well-suited to handle the wild weather swings we can experience in Louisiana. There are myriad flower colors and sizes to choose from, all of which attract a wide array of pollinators. Irises prefer full sun and typically bloom from late March through April, going dormant in the hot and dry late summer weather of August and September. Once temperatures cool off in November, Louisiana iris plants will once again start growing and provide striking sword-like green foliage throughout the winter when most other garden plants have gone dormant. Louisiana irises are highly adaptable plants that can make beautiful additions to water features and ponds. The term “Louisiana iris” is a common name that refers to the five different native species naturally found in Louisiana and the hybrids of these species. Louisiana is home to several fantastic iris breeders that have released gorgeous and unique cultivars on the market, and the best time to find Louisiana iris plants at retail garden centers is in the spring — just before and during their blooming season.
For summer we are excited to promote the summer of salvias! We believe the pollinators are excited about this, too. For years we have wanted to include more salvias in the Louisiana Super Plants program, but we could never decide on just one cultivar because there are so many amazing choices on the market! With the need for flexibility, we have decided that we don’t have to limit our choice to a single salvia. Instead, we have recommended a “summer full of salvias.” Additionally, summertime ushers in patriotic feelings for everyone, so we decided to focus on a red, white and blue color palette! We have five cultivars to announce, including:
1) Roman Red — Showy crimson red flowers fully adorn this dense, bushy salvia. Plants have done quite well with average drainage in full sun, and they bring a pop of bright color to the front or middle of the landscape bed.
2) Skyscraper Orange — While technically not red, the dark orange color is a close match, and it is too good to not include! Growing larger than Roman Red with taller flower spikes, this excellent performer stands out at the back of landscape beds and tolerates rainfall and average drainage like a champ. As a bonus, it may perennialize in average to warmer winters!
3) White Flame — White is not a color often associated with salvias, but this amazing new Salvia farinacea shines like a beacon in the landscape. The plants tolerate heat extremely well and may also perennialize in warmer winters, allowing it to bloom earlier in the spring.
4) Mystic Spires Blue (improved) — With its tall spikes of vibrant blue flowers rising above lush foliage, Mystic Spires Blue is one of the showiest salvias on the market. The plants remain compact and bushy, and they tolerate heat and humidity quite well.
5) Rockin’ Blue Suede Shoes — Get ready to rock out all summer long with these fantastic light blue flowers contrasted against dark calyxes. These are big plants, so give them plenty of room! Blue Suede Shoes should easily perennialize in average winters.
Finally, we wanted a plant choice for autumn that perfectly embodies the feeling and colors of the harvest season. And who doesn’t love ornamental peppers? We plant them every year at the Hammond Research Station, and after many years of trying to identify the best, we have decided that this might be an impossible task! Therefore, we are including ornamental peppers as an entire group into the Louisiana Super Plants program. With their tolerance for persistent heat and an eye-catching range of foliage and fruit colors, these plants are the perfect way to both spruce up the late summer landscape and celebrate the transition into fall. While all ornamental pepper cultivars that are found in Louisiana nurseries and garden centers will be considered Louisiana Super Plants, some of our favorites are: Midnight Fire, Black Hawk, Hot Pops Purple, Chilly Chili and Calico. For some added fun, throw in some edible ornamental peppers like Mad Hatter or Candy Cane Red, since peppers labeled solely as “ornamental” are typically not suitable for consumption.
For more information on Louisiana Super Plants, please contact the Hammond Research Station 985-543-4125 or your local LSU AgCenter extension office.
Jeb Fields, Ph.D.
Extension Specialist for Commercial Ornamental Horticulture
Heather Kirk-Ballard, Ph.D.
Consumer Horticulture Specialist
There seems to be a trend in vegetable gardening among homeowners these days. Over and over on social media, in emails and phone calls to the LSU AgCenter, we keep hearing about people not finding success in the vegetable garden. My favorite is the garden meme that says something like “invest $70 into a backyard garden and get a return of $750.” These posts usually evoke responses such as “I only make one or two tomatoes,” or “my bell pepper plants are stunted,” or “that horrible squash vine borer just will not leave us alone!” Someone will comment, “Yeah, right. I invested $2,000 and got 10 really expensive squash and two okra pods.” Sometimes these statements are accompanied by photographs to prove the point of being unsuccessful. Sometimes AgCenter extension agents visit home gardens to see the problem, and sometimes people are simply venting their garden woes online without also indicating what might have gone wrong.
I want Horticulture Hints readers to know that you can be successful in the vegetable garden. Success in the garden, like success in everything in life, comes with a little grit, elbow grease, and the ability to see problems and not run away. Below are a few tips I’d like you to try this summer. These tips will not solve all your problems, but they are a start. Keep letting us, the LSU AgCenter, know what problems you are having (along with a photo or two of the problem) so we can help set you back on the path of success.
Solution: Have you applied fertilizer? Nine times out of 10 the gardener did not incorporate any fertilizer into the soil — or not enough fertilizer. Start with a 13-13-13 fertilizer broadcast into the soil before planting your seeds or seedlings. Let’s just use a medium rate of fertilizer as an example: Use 5 to 6 pounds (10 to 12 cups) of 13-13-13 per 300 square feet. If your garden is only 100 square feet then you would use 2 pounds or 4 cups of 13-13-13. If you have a 4-foot by 8-foot raised bed, that is 32 square feet and you should apply about 1 pound (actually 0.62 of a pound, but round up and make it easy). That would be 2 cups of 13-13-13 before planting. But that isn’t all. You also need to fertilize again when your summer plants begin to bloom. I like 1 tablespoon of calcium nitrate, which is 15% nitrogen, between every other plant. Apply every other week through harvest. You can also use a basic blue water-soluble fertilizer. Those are usually 15% nitrogen as well, and you would apply 1 tablespoon per gallon of water and drench your plants every other week through harvest. This extra bump of nitrogen really increases plant growth and yields.
Solution: Move. Seriously, just get a new house and a new garden. We know it is not practical, but once these moths find you, they have written your address down in their book. So, start by covering your cucurbit plants with insect netting. The netting lets in light but also keeps adults (moths) off your plants. Remove the netting after flowers begin to open. Now you need bees. Otherwise, you will have beautiful plants and vines and no fruit. Next, the moth will come back to find you, so be prepared. Scout your plants three to four times a week. As soon as you see the holes be prepared to mix up an insecticide with the active ingredient bifenthrin. Mix it according to the label. Don’t guess. If you guess then it won’t work for any of us because the larvae will eventually become resistant, and the chemical does not work anymore. Spray the solution right where you see the small hole with “saw dust” coming out of it. That should kill the larvae. You don’t want to use insecticides? Use an X-Acto knife, cut a 1-inch slit parallel with the vine above and below the little hole with sawdust coming out of it. Hand remove the larvae and wrap the vine back together with a small rubber band just tight enough to keep it together without choking off the plant. Also, try not growing any cucurbits for one year. Let the moths go somewhere else and then slowly get back into it.
Solution: Convince your neighbor to grow a vegetable garden and give you the excess. I kid that the only people saving grocery money are those people who live next door to a vegetable gardener. All kidding aside, remember this is a hobby for you. It’s also a form of exercise. Cut the gym membership and buy an extra bag of fertilizer and flat of plants. Well, you say, I still need to go to the gym. I agree. I should be there too. Think of the garden as your own private meditation. Breathe in fresh air. No one is bothering you because the kids think you’re giving yourself a chore. In the crazy busy world we live in, we do not spend enough time outdoors being in nature and watching slow growth and tiny blooms. Turn off your phone, order in dinner — because you know you will be out there until 8:30 p.m. — and think of this as an alternative to therapy. Some reading this article will say, “I don’t need therapy. This is still not saving me money.” Here is my last solution to help you save yourself money in the garden:
|Find a 5-gallon bucket in your shed that has a crack or a broken handle. Do not throw it out.
|If the crack is not big enough, hit it with a hammer and make it bigger. We need drainage.
|Fill it with a decent potting soil. Yes, go buy a nice bag of potting soil.
|Plant three to five cucumber seeds in the bucket. Once they emerge, thin them down to two plants. Or purchase one cucumber seedling and plant it in the middle of the pot.
|Insert one tomato cage into this 5-gallon bucket.
|Water each night as you come home from work.
|When it starts to bloom, give it a little fertilizer, as I mentioned in problem/solution Step 1. You do not need to add any before planting if this is fresh soil with a fertilizer already in it.
|Email me and tell me how many cucumbers you picked off that single plant this summer.
You will feel good, I promise! And, just maybe, you will plant a second bucket next year.
Enjoy the Garden,
Kathryn “Kiki” Fontenot, Ph.D.
Vegetable Gardening Specialist
LSU AgCenter School of Plant,
Environmental and Soil Sciences
Summer is the peak growing season for lawns in Louisiana. If you did not fertilize during the spring, you still have time to fertilize and get your yard in good shape prior to fall. Keep up a good fertility program through early to late August. Remember to apply all granular materials on a dry lawn and water very soon after application. Make sure lawns are getting adequate amounts of moisture during the summer months, but don’t overwater. Water deeply only once or twice per week or as needed based on the amount of rainfall. The purpose of irrigation is to supplement rainfall. I am not a fan of watering lawns everyday unless we are in severe drought.
Consider aerifying compacted soil. I’ve seen aerification completely change thin lawns caused by compacted soil into thick and healthy turf. Aerifying helps with water percolation and increases the turf’s rooting depth and makes for a more drought-tolerant lawn. Lawn care companies can aerate, or you can rent an aerator from a rental store and do it yourself. If your soil is prone to compaction, consider aerating one to three times this growing season. Aeration may be the game changer that your lawn is missing.
St. Augustinegrass and zoysia both respond well to fertilizer applications. St. Augustinegrass may be fertilized up to three times during the growing season in April, June and mid-August. Fertilize zoysia twice per growing season in April and again in July.
Bermudagrass is an even bigger fertilizer user and can be fertilized from three to five times during the growing season, especially if you like to mow grass. Carpetgrass and centipedegrass are not big fertilizer users. Up to two applications (in April and an optional application in July) will take care of centipedegrass, and a single application will be sufficient for carpetgrass (April).
Centipedegrass should receive its second and final fertilizer application in July. For centipedegrass, apply only one-half pound of actual nitrogen per 1,000 square feet. For example, apply 3 pounds of 17-0-17 per 1,000 square feet or 5 pounds of 10-0-10 per 1,000 square feet. St. Augustinegrass would need 6 and 10 pounds of the aforementioned fertilizers. If your lawn is not performing well, there could be a nutrient deficiency in the soil. The only surefire way to know what your soil needs is to collect a soil sample and submit it for testing at the LSU AgCenter Soil Testing and Plant Analysis Lab. To simplify the soil sampling and submission process, there are pre-addressed submission boxes with sampling instructions at several garden centers throughout the state and at your local parish extension office. Once submitted, the results will be sent to your home mailbox and or email, usually in less than two weeks. Your parish LSU AgCenter extension agent can help you interpret the results from the soil sample and tell you exactly what’s needed nutrient-wise to make your lawn beautiful.
You may not know this, but there is a correct mowing height for your lawn. St. Augustinegrass is very finicky when it comes to mowing height. Don’t cut it too short and don’t allow it to get too tall. It likes to be maintained around 3 inches, the tallest mowing height of all the lawns grown in Louisiana. If you cut St. Augustinegrass too short, it becomes stressed and more prone to disease and weed infestations.
Centipedegrass is often maintained too tall. Centipedegrass should be mowed to 1 to 1.5 inches. This helps prevent thatch buildup. Zoysia also likes to be mowed in the 1-to-1.5-inch range. Bermudagrass should be mowed from 1 to 2 inches, shorter mowing heights are better when more frequent mowing is possible. Keep mower blades sharp to ensure a clean cut and good lawn health.
Watch for chinch bugs in St. Augustinegrass and bermudagrass lawns and treat with an LSU AgCenter-recommended insecticide such as bifenthrin (Talstar and many other trade names). Chinch bug problems show up as yellowish-brown to straw-colored areas of the lawn during hot, dry weather. These insects extract plant juices from turfgrass stems and crowns while pumping toxic salivary fluids into the lawn. The fluids disrupt the plant’s vascular system. The damage actually resembles herbicide damage. Check for chinch bugs in the lawn by saturating suspected areas with a gallon of water mixed with a few squirts of lemon dishwashing soap. This soapy solution irritates chinch bugs and brings them up near the grass surface so you can see them and determine if the bugs are causing the lawn damage. If it’s hot and dry and there are dead spots in your St. Augustinegrass, chinch bugs are the first thing that I would consider.
Additional insect problems that appear during the summer include armyworms and tropical sod webworms. These moth larvae or “worms” can cause severe lawn damage very quickly and will need to be killed with insecticides to prevent further damage. Tropical sod webworms can devastate St. Augustinegrass and carpetgrass lawns. Tropical sod webworms crushed St. Augustinegrass in 2020. However, populations were not severe in the 2021 growing season. Armyworms prefer bermudagrass and can completely defoliate acres of pasture and lawns. Carbaryl, bifenthrin and chlorantraniliprole insecticides are options for tropical sod webworms, armyworms, as well as chinch bugs infesting the lawn.
Be mindful of these pests as you walk through your lawn. Investigate damaged areas and treat accordingly.
In late spring to early summer, Virginia buttonweed starts forming mats that can eventually smother out the lawn. Pull up small populations of Virginia buttonweed or carefully treat with herbicides like metsulfuron (MSM Turf and other trade names) or Celsius. These herbicides work well with repeated applications spaced four to six weeks apart. Metsulfuron and Celsius can be safely applied on St. Augustinegrass, centipedegrass, bermudagrass and zoysia during warm weather. Carpetgrass will be damaged by the herbicide Celsius. Bahiagrass will not tolerate metsulfuron or Celsius. When it comes to “managing” buttonweed it is important to start spraying early in the growing season (April) and spray often. Don’t wait until September to make your first herbicide application.
Common lespedeza is a mat-forming annual legume that emerges in the spring and lingers deep into fall throughout Louisiana. By late summer, the plant matures and becomes woody-like and tough on lawnmower blades. Metsulfuron works well on this weed, but early summer applications are more effective.
Torpedograss is a perennial grass that’s mainly a problem in south Louisiana, but I do get calls about it from north Louisiana as well. There are few lawn problems more devastating than a torpedograss infestation. Torpedograss is extremely tolerant of herbicides and easily outcompetes slow-growing grasses like centipedegrass.
The weed often starts from soil brought in during flower bed construction. However, it quickly spreads from the flower bed to the lawn. The ability to suppress torpedograss in lawns depends on the turfgrass species. Selectively removing torpedograss out of lawn grasses and sports fields is rarely completely achievable. Quinclorac (Drive and other trade names) is an herbicide that is somewhat effective in suppressing torpedograss in bermudagrass and zoysia. Unfortunately, you cannot use quinclorac in centipedegrass and St. Augustinegrass.
Sethoxydim (Bonide Grass Beater and other trade names) will temporarily injure torpedograss infesting centipedegrass, but it does not provide long-term control. The torpedograss recovers and the weed re-infests the centipedegrass. Unfortunately, there are no selective herbicide options for torpedograss infesting St. Augustinegrass. Often, complete renovation is necessary when centipedegrass and St. Augustinegrass are severely infested.
If you decide to renovate and install a new lawn, consider sodding the lawn with zoysia (semi-shady or full sun lawns) or bermudagrass (for full sun only). Converting to zoysiagrass or bermudagrass will allow the use of quinclorac, the most effective selective herbicide on torpedograss. Installing zoysia may be the better fit for Louisiana because of its good shade tolerance and drought tolerance. Zoysia is not a high maintenance grass when managed properly. Maintain zoysia at 1 to 1.5 inches with a sharp mower blade and fertilize twice per year. There are several sod farmers in Louisiana that grow zoysia, so it is readily available.
Proper lawn maintenance keeps your lawn healthy and reduces the need for the use of pesticides. If it becomes necessary to use a pesticide in the lawn, it is highly important to always read and follow their labels before using. The label will tell you how to use the product safely to achieve satisfactory results. You will find the label attached to the product’s container.
Ron Strahan, Ph.D.
Weed Scientist and Turfgrass Specialist
A new disease, Pestalotia leaf spot and fruit rot, which is caused by the fungus Neopestalotiopsis species, has been detected in strawberries in Louisiana. An aggressive form of this pathogen was first detected in Florida during the 2018-19 growing season. The disease has since been confirmed in Georgia, North Carolina and Texas. More recently, the pathogen has been detected in strawberry fields in south Alabama.
Initially, the pathogen causes leaf spot and fruit rot but later infects crowns and roots, leading to plant death. Leaf spots vary in size and are light to dark brown with tan centers. Similar spots appear on the fruits, but these spots are slightly sunken and cause rotting of fruits. As the disease progresses, tiny black fungal fruiting bodies appear on both leaf and fruit spots. These fruiting bodies produce spores under favorable environmental conditions. The disease favors extended rainy weather, and disease development is optimal between 77 to 86 degrees F.
The disease spreads to new strawberry fields by means of infected transplants. Once introduced, the pathogen spreads within a field or to nearby fields by rain splashes and irrigation water, contaminated field equipment, and field workers. Successful disease management requires integrating cultural and chemical control practices. Growers must buy disease-free, healthy transplants to avoid introduction of the pathogen to new fields. Careful inspection of transplants is necessary, as initial disease symptoms may not be readily visible. Sanitation of farm equipment is helpful in reducing local disease spread within and to nearby fields. Farm workers should limit field activities when plants are wet.
The leaf spots and fruit rot caused by Neopestalotiopsis species can be easily confused with other strawberry diseases; therefore, accurate diagnosis and identification is required. If you suspect this new disease in your strawberries, please contact your local parish agent. The LSU AgCenter Plant Diagnostic Center is available for your plant diagnostic needs. If you need more information regarding sample submission, please call 225-578-4562 or visit our website at www.lsuagcenter.com/plantdiagnostics.
Raj Singh, Ph.D.
Director, LSU AgCenter Plant Diagnostic Center