Lafayette Parish Master Gardeners

GERALD'S CORNER

By Gerald Roberts
Horticulturist/Master Gardener Program Coordinator
LSU AgCenter

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April  2016

4/1/2016

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Hello Master Gardeners,
April presents us with more opportunities to expand our gardening activities. April affords us additional warm or hot-weather vegetables to plant. April allows us to plant many vegetables that will be more productive if planted this month instead of waiting. The earlier certain vegetables are planted, the more productive they are. Especially if they can avoid very high temperatures when they are at the peak of their productive cycle and also if they are less challenged by insect pests. Vegetables that are recommended to be planted in April are cantaloupe, collards, corn, cucumber, eggplant transplants, snapbeans, Southern peas, squashes, watermelon and tomato transplants. Tomatoes are staked to keep the plants form sprawling on the ground where the fruit would be more likely to rot. Wait for the first flowers to appear, and place the stake on the opposite side of the plant’s stem. All of the flower clusters will grow from the same side of the stem and this will keep developing fruit from getting caught between the stake and the stem.

For those who love to plant herbs, basil, sesame, lemon balm, mints, lemon grass, lemon verbena and rosemary can be planted in April. Excellent hot weather vegetables that can be planted in late April include eggplant, peanuts, pumpkin, Southern peas, hot pepper, lima beans, luffa gourds, and okra.

Pruning of spring flowering shrubs such as spirea, viburnum, quince, azalea, camellia, jasmine and mock orange can be done as soon as they complete their blooming period. Remember though, that pruning should be the result of a specific purpose. Unless you are trying to achieve a clipped formal hedge, pruning should be done to preserve the natural shape of the shrub. Clipping or shearing creates a hedge look, but if you’re trying to lower the height of a shrub, selective pruning should be done by taking the tallest branch or shoot and lowering it by cutting down into the shrub. Then take the next longest and continue this procedure, moving on to the next tallest branch until the shrub is lowered to the desired height. By selectively pruning, you preserve the more natural shape of the shrub instead of shearing across the top making it look more like a hedge.

Be sure to mulch newly planted beds or shrubs or bedding plants with a 1 -2 inch layer of leaves, pine straw, pine bark, or other organic material. The benefits of mulching include suppression or control of weeds, conservation of moisture, reduced soil compaction, and improved soil structure. As mulch decomposes, it provides nutrients to the plants and moderates soil temperatures.

Generally, during hot dry weather spider mites become active and the damage may show up on many vegetables and ornamentals. Spider mites are not easily detected by the naked eye. Using a magnifying glass to inspect the plants, look for tiny red or green eight-legged mites. The foliage of infested plants appears dull, dusty and unhealthy, and eventually turns brown. The spider mites are located primarily under the leaves. Spray with a horticultural oil, insecticidal soap, Malathion or a miticide called Kelthane.

Plant caladiums this month. Caladiums are excellent for shady areas and combine beautifully with ferns, begonias, liriope, impatiens, hosta and coleus. Some outstanding perennials that many nurseries have available at this time of the year in gallon containers include perennial salvia, bee balm, butterfly weed, chrysanthemum, coneflower, coreopsis, four – o’clock, gaillardia, gerbera daisy, daylily, mallow, Goldsturm rudbeckia, sedum, Shasta daisy, stokesia, verbena, yarrow, and violets. Even though some nurseries may still have cool season annuals for sale, think twice before purchasing those for transplanting since cool season annuals will struggle in hot temperatures. Even though petunia will tolerate some heat, even the heat-tolerant ones like the Wave series may last longer but still tend to struggle in the intense heat in late June and into July and August.

Azaleas with leaves that have tiny light spots all over them have been attacked by the azalea lace bugs. Treat with Malathion or Orthene (acephate) as needed through the summer and fall. Any damage that has already occurred will not go away, but insecticide applications will prevent further damage. Spray crape myrtles with mancozeb, chlorothalonil, or other labeled fungicides to control powdery mildew. Powdery mildew appears as a white powdery material on the leaves. Unlike many fungus diseases that are worse during rainy weather patterns, this disease is favored by humid, warm weather without rain. Powdery mildew can also be a problem on a variety of other landscape plants such as dogwood, euonymus, gerbera daisy, rose and hydrangea.
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Master Gardeners, the time has come for me to bid you all good bye. Beginning in 1976 immediately after college, I began going to work every day hoping make a difference in the lives of people. As a young person beginning a career in a profession that serves people, I was told by someone older and wiser than myself to always remember that people don’t care how much you know until they know how much you care. Thank you all for caring, and I hope my attitude with each of you individually and collectively reflected how much I cared. The Lafayette Parish Master Gardeners Association will continue to serve and thrive because of each of you. Your passion for serving others speaks volumes for how much you care. Let us all look ahead with the greatest amount of optimism possible, and never look back with regrets. Thank each you for making me better as a person. I’m light years ahead of where I was when I came to you all in January of 2010. Thanks also to the LSU/Southern Universities AgCenters for giving me a chance. To the Evangeline, St. Landry, and Lafayette Parish Extension Staffs, I hope I’ve given you all as much as you all gave me. I feel that you gave me all the support and encouragement that a person could ever expect. FAREWELL!!!

Gerald P. Roberts, Horticulturist/Master Gardener Program Coordinator
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March 2016

3/1/2016

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March Garden Tips
For vegetable gardeners, as soon as the weather is favorable and the soil is dry if you haven’t already started, you can begin tilling and preparing the soil for your Spring garden!! I was at several garden centers around the Lafayette area during mid–February and gardeners purchasing vegetable transplants and seeds was brisk.

Most gardeners understand planting early does come with some risk from the possibility of freezing, they like a challenge and feel if they can cheat mother nature, they’ll be rewarded with early harvesting of vegetables. The other advantage of planting early is increased production during milder temperatures and usually less pest problems. A free copy of the Louisiana Vegetable Planting Guide can be obtained from the parish LSU Extension Office.

Seeds of the following vegetables can be planted this month: cantaloupe, collards, corn, cucumbers, cucuzzi, lima beans, mustard, radishes, snapbeans, summer squash, Swiss chard, and watermelon. Plant transplants of the following: kohlrabi, peppers, and tomatoes. Mirlitons are planted now using the entire fruit with the sprouted end buried in the soil about 3 inches deep.

This is also the month that warm season bedding plants can be transplanted, so begin preparing the soil in landscape beds. Consider using root stimulants or starter solutions when transplanting warm season bedding plants, and pay attention to plant depth, being careful to set the plants at the same depth they were growing. A one inch layer of an organic mulch will help to suppress weeds, reduce soil compaction, and conserve moisture. It may take an average of a month for bedding plants to become established, so during this time be sure they are not allowed to dry out. Once the root system is established, less supplemental water will be needed. Sometimes after March 15th depending on temperature, it should be safe to plant tender bedding plants such as marigolds, zinnias, blue daze, pentas, celosia, salvia, portulaca, and melampodium.

Continue to plant roses purchased in containers, but bare root roses are still available at various garden centers even though they should have been planted last month. Once bare root roses begin to sprout, take extra care when selecting, planting, and caring for them until they become established. Summer flower bulbs can be planted beginning in late March or early April. Since most of these bulbs are tropical, it may be well into April or May before they begin to make accelerated growth. It is best to wait until April to plant caladiums since it’s preferable to plant caladiums in warm soil.

Established perennials should be fertilized this month. This is most efficiently and economically done by using a granular fertilizer with a 3 : 1 : 2 ratio (a fertilizer similar to 15 – 5 – 10 ) which means 15 % nitrogen, 5% Phosphorous, and 10 % Potassium. In terms of the amount and method of application follow label or packaging directions. After the fertilizer is applied, water the bed to wash any fertilizer granules off the foliage and down to the soil, since many fertilizers contain salts and can burn tender foliage.

As the weather/temperature warms up, lawn grasses will begin to grow and mowing will be needed. Sharpen mower blades as mowing needs become more frequent. However, this is not the time to fertilize lawns since fertilizing lawns while the soil temperature is cold will not allow the grass to efficiently pick up the fertilizer, and fertilizing too early can aggravate brown patch disease. The first application of fertilizer should be around the first week in April. I know it’s common to apply weed and feed products early in Spring, but keep in mind that weed and feed is a blend of a herbicide for weed control and a fertilizer. Instead, it’s preferable to concentrate on broadleaf weed control this month by applying one of the 4 way blend herbicides such as Ortho Weed B Gon or Fertilome Weed Free Zone.

Scout roses for thrips which are a common problem on roses in Spring and early Summer. Thrips are tiny insects that infest the flower buds. Symptoms include buds that don’t open properly, and when the flower does open, the petals have brown scorched edges. Thrips don’t damage the bush but can ruin the flowers. Spray once or twice weekly with Acephate or Mavrik for control. Fertilize rose bushes in early March, and also begin spraying to control insect and disease problems. For convenience there are several products available for rose growers that are formulated with both an insecticide and a fungicide in the same product.
Powdery mildew is a fungus disease that is common on the new growth of many plants that usually begin to show up this month. This disease appears as a powdery covering on the leaves or flower buds. Severe infection can lead to foliage being damaged and flower buds can drop. Look for fungicides labeled for control of powdery mildew, one of which is chlorothalonil.

It is a common practice for some gardeners to apply aluminum sulfate or lime to the soil around their hydrangeas to influence flower color. Aluminum sulfate causes the flowers to be blue , and lime causes the flowers to be pink. Since flower buds should already be present, don’t prune hydrangeas at this time.

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February 2016

2/1/2016

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Hello Master Gardeners,

Recently I’ve been receiving calls and pictures regarding camellia flowers being discolored after opening or some being discolored and only partially opening. On white camellia flowers the flower petals take on a tan to brown color and many fall to the ground. After discussions with Dr. Raj Singh, LSU AgCenter Plant Pathologist , and Director of the Plant Pathology Lab at LSU, we concluded that the majority of the problems were caused by cold injury. However another problem that mimics cold injury is Camellia Flower Blight which is caused by Sclerotinia camelliae which becomes active during cool moist conditions.These conditions are what Dr. Singh refers to as favorable conditions for camellia flower blight. To those of you who had the fortune of sitting through Dr. Singh’s plant pathology class as you received classroom instructions to become a certified Master Gardener, you should have recalled that he said in order for infection to take place there are three things that need to be present: favorable conditions , a host, and a pathogen. When camellias are blooming in cool temperatures with abundant moisture, camellia flower blight is highly probable. Camellias growing in shade where moisture is more abundant are more susceptible. The fact that camellia flower blight mimics cold injury may be confusing to home gardeners because of the similar appearance, but remember, if the petals have a slippery, slimy texture then it’s camellia flower blight. If the discolored petals have a dry leathering feel then in all likelihood it is cold injury. If it is camellia flower blight all infected flowers that fall to the ground should be picked up and discarded. Some gardeners even picked the infected flowers off the plant and discarded them. If this is not done, the pathogen will over winter in the old infected flowers and be there to infect the next crop of camellia flowers.

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I’m also receiving numerous calls from home gardeners regarding a high number of broccoli plants that are bolting or as old gardeners say, going to flower and seed. We see this occurring when these plants are repeatedly exposed to warm temperatures, which is common with late season broccoli. If you recall we’ve had several periods of above normal temperatures and since I’m getting calls from all across Lafayette and surrounding parishes it’s safe to conclude that the warm weather patterns are to blame. Bolting is actually a survival mechanism in certain plants , where by if the temperature ranges are higher than what the plant has been genetically programmed to handle, the plant feels threatened and tries to produce the next generation by flowering, followed by seed production. Some research indicates that to some degree as a gardener these plants can be mulched or watered to keep the roots cool which may minimize bolting. However, I’m not sure if that has been proven! All cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts, turnips , kale, cabbage and several others, are susceptible to bolting!!

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One of the most serious diseases of cruciferous crops worldwide is Black Rot caused by the bacterium Xanthomonas campestris. If the pathogen is present in seeds or transplants, and favorable conditions develop such as wind and rain producing splashing water, it is highly likely that infection will take place. Many gardeners have called and sent pictures of browning of the leaves of broccoli, cabbage, and cauliflower within the last month. They should remember the rainy weather pattern we’ve been having and continuing to have. The infection usually begins on the leaf margins where the pathogen enters the plant through natural openings in the leaf or through insect wounds. The leaves begin to take on a tan to brown V shaped lesion in its early stages and progressively moves downward from the leave margin to consume an increasingly larger area of the leaves of these vegetables. This causes plants to sometimes die prematurely, remain small, or lowers the quality of the vegetables produced. Symptoms are sometimes confused with nutritional problems. In the very early stages of development, infected leaves can be removed and applications of copper fungicide can be made to slow the spread of Black Rot.

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Gerald P. Roberts
Horticulturist/Master Gardener Program Coordinator
LSU AgCenterhere to edit.
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January 2016

1/1/2016

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Happy New Year Master Gardeners!!!
Welcome to a new year and new opportunities to make a positive difference in the lives of others; and also for opportunities for our personal growth and development in the area of horticulture and gardening.

Citrus continues to gain popularity among gardeners here in south La. The reason being that in addition to not requiring a lot of management, citrus fruit are delicious and vitamin rich. The one limiting factor in terms of production in this area is cold damage which can severely injure or kill citrus. Because it’s been several years since the last time we had killing cold temperatures, many gardeners have citrus trees that are producing quality fruit. As we approach winter, gardeners must remain vigilant about watching the weather for predicted freezing temperatures along with being prepared to protect trees if needed. There are a few things I’d like to point out to gardeners who at the first prediction of freezing temperatures begin placing calls to the Extension office with question about how to protect citrus trees. It must be noted that in order to be prepared, one must understand cold hardiness and the way it relates to citrus. Cold hardiness refers to a plant’s ability to withstand or survive freeze temperatures without being seriously injured or killed. In terms of cold hardiness kumquats are the most cold hardy, followed by Satsumas, Sweet oranges, and grapefruit, with lemons and limes being the least cold hardy. The old saying by many older gardeners regarding citrus is that sweet fruit can take more cold temperatures and survive than sour fruit. I wonder if that is the reason why we frequently see older kumquat trees on old home sites rather than older lemon trees? It is very important to manage citrus trees to maintain good health because as a general rule healthy trees usually tolerate more cold temperatures, as do older mature trees. It must be noted that anytime the temperature drops below 32 degrees the potential for damage to the fruit on the trees is possible. As temperatures approaches the mid – 20’s and below, the potential for damage to the actual tree becomes increasingly possible. One of the unique things about citrus is that mature fruit can remain on the tree and can be harvested as needed. However, whenever a freeze is predicted, especially if freezing temperatures are predicted for several hours, it becomes more likely that the quality of the fruit on trees will be affected. Long story short, keep an eye on the weather and predicted freezing temperatures and remove fruit anytime a freeze is predicted, especially for several hours. Remember if trees are covered with plastic overnight, that plastic covering should be removed the following morning to avoid damage from heat buildup especially if the sun is shining the next day!!

Winter and early spring are generally the optimum time for gardeners to prune most plants in the home landscape. Every year especially as winter arrives, many calls come into the Extension office regarding pruning of specific plants; mostly questions about when is the best time to prune. Many times I wish the first question would be - I have a particular type of plant and I’d like to know if it requires pruning? Plant species vary in terms of if they need pruning and how much should be removed when pruned. Believe it or not, there are many gardeners who prune only because they read about pruning , or saw someone pruning, and just assumed that the plants in their landscapes needed pruning. It must be kept in mind that before pruning a plant you should decide if you’re pruning for a specific purpose. Gardeners probably should ask why prune before asking when to prune. As Certified Master Gardeners, you’ll be asked or will be a part of conversations regarding pruning especially at this time of the year. While there are no specific etched- in- stone rules for pruning, gardeners should not be afraid to try their hand at pruning. Be sure that you’re pruning for a purpose, you have the right tools and use the proper pruning techniques. Some considerations regarding pruning that gardeners should be aware of is that once the decision to prune is made, preserving the natural form or character of the particular plant species is important. It is also important to note that some shrubs may require annual pruning, while others may not. However it is better to do a little pruning each year than to drastically cut back a plant that has been neglected for several years. For example, if pruning to lower or maintain a certain height for a particular plant species, lower the height by selectively removing branches or canes at varying heights instead of shearing straight across the top of the plant which will destroy the natural form of the plant. On small branches or wood the size of your fingers, the type of pruning technique is not as critical as when you begin removing larger branches. That is when it’s important to make proper pruning cuts. Cuts should be make just outside the wrinkled area where the limb or branch attaches to the main trunk, which promotes callusing and healing of the wound. However if you cut too far inward and into the wrinkled area, this will result in a flush cut that severely restricts healing, leaving your plant susceptible to insects or disease-induced rot.

There was a time that whenever pruning cuts were made on a plant, the wounds would be painted with special pruning compounds to prevent entry of insects or diseases and to promote callusing. But now it is believed that these compounds actually do more harm than good. As a result, pruning paint, pruning sprays or other compounds are not recommended being applied to pruning cuts or wounds.

Before making the decision to prune, ask Why. Does the shape of the plant need to be influenced or altered? Does the size of the plant need to be controlled? Are there any dead or diseased branches that need to be removed? Are there any parts of the plant that are severely infested with insects? These are the questions that should be asked before deciding to prune a plant. No plant should be pruned without a specific purpose or goal by the gardener. Finally, remember that plants should be selected for placement in the landscape based on their expected average mature size, including height and spread. Too often plants are placed in areas where they outgrow the space and gardeners are forced to constantly battle to maintain the plant at a certain size which leads to frequent pruning. So making the right decision regarding plant selection and placement will go a long way in keeping gardeners out of a constant battle with mother nature. Once you get into a battle to control the size of a plant, you’ll realize that mother nature doesn’t give up!! Remember, if in doubt as to how to properly prune, or when to prune or why to prune, the LSU AgCenter website provides great information. There are also great how- to books on pruning that should be a part of every Master Gardener’s gardening resources.

Happy Gardening in 2016
Gerald P. Roberts
Horticulturist/Master Gardener Program Coordinator
LSU AgCenter
1010 Lafayette Street, Suite 325 Lafayette, LA 70501, GRoberts@agcenter.lsu.edu
Office (337) 291-7090, Fax (337) 291-7099
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December 2015

12/8/2015

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For this month’s horticulture article I’d like to share information regarding timely issues in home landscapes as evidenced by the calls and emails I’m currently getting from gardeners. In the Fall of the year — especially if we have a lot of rain — we get numerous calls regarding brown patch disease in lawns. Even though brown patch disease can be problematic in other warm season turf grasses such as centipede and Bermuda, the majority of calls are regarding issues with St Augustine grass.  Brown Patch is a fungus disease caused by a pathogen called Rhizoctonia solani. It has been referred to as a spring-and-fall disease since it has a tendency to be more active when we have moderate temperatures (60 – 75 degrees) especially and high moisture. At 80 degrees and above, and under dry conditions, the activity of the fungus decreases significantly. Once temperatures begin to moderate in the fall the first indication of an infection in the lawn is a small-to-moderate irregular brown/tan circle which increases in diameter as temperatures moderate and rainfall increases. Within the circle there are green blades of grass among the tan straw colored grass.   

Additionally the grass within the irregular brown circle can be pulled easily because it is rotted at the  base.  Once a lawn has a history of brown patch disease it is more likely to show up anytime temperatures moderates and there is high moisture. In St. Augustine the grass takes on a yellowish, yellow–orange color, in centipede it will lean more toward a purplish color. Once daytime temperatures reach 80 degrees F or above, even in the summer months there may be areas that get brown patch disease usually in shady areas under or next to trees or in enclosed back yards where there is little air movement. Issues that increase the incidence of brown patch are watering late in the afternoons which allows leaf blade to remain wet overnight. Applying fertilizer past the end of August or fertilizing before the first or second week in April can increase brown patch disease, and thus heavy thatch problems. When brown patch occurs, treat promptly with a fungicide containing one of the following active ingredients. The following fungicides are labeled to control brown patch diseases in lawn grasses, Myclobutanil (Ferti – lome F Stop, Green Light Fung Away, Spectracide Immunox), Thiophanate – Methyl (Ferti – lome Halt, Scott’s Lawn Fungus Control, Southern Ag Systemic Fungicide), Triadimefon (formerly Bayleton, Bayer         
Advanced Fungus Control, High Yield Lawn Fungicide). Two applications 10 – 14 days apart provide the best control. On a personal note, let me emphasize that increased rainfall not only interferes with effectiveness of fungicides but it also increases fungus activity. Always follow label instructions in terms of safety, recommended rates and application.                  

The surge in popularity of citrus in home gardens is at an all-time high due to it being several years since we’ve experienced freeze intense enough to kill mature citrus trees. Satsuma is very popular due to the high quality that can be produced by homeowners and the ease at which they can be peeled because of their loose skin compared to sweet oranges. Keep in mind also that when the decision to plant citrus is made, cold hardiness must be a priority. Kumquats and Satsuma are the most cold hardy with Lemons and Lime being the least cold hardy. Sweet Oranges, Navel Oranges and Grapefruit fall somewhere in between Kumquats and Limes in terms of cold hardiness. One of the most common complaints that I get from homeowners is a condition referred to as puffy fruit in Satsumas. Puffy fruit are mostly a problem on young, vigorous growing Satsuma trees. These fruit are unusually large, have thick rinds and relatively dry flesh. As the tree becomes older, the occurrence of puffy fruit decreases. There is some thought that trees go through a juvenile stage and once passed this stage, fewer puffy fruit are produced. On older mature trees, even though it occurs a lot less, puffiness can occur, but these fruit are thought to be due to late blooms that set fruit during periods of warm weather. Although little can be done to prevent puffy fruit, good growing conditions, proper fertility, pest control, and time will help to reduce this condition. Two of the more popular types of Satsuma are Brown’s Select, which begins ripening in mid–October, and Owari, which produces excellent quality fruit and begins ripening from early to mid–November. The fruit of Satsuma keeps well on the tree and can be picked and eaten over a three-to-four-week period and still maintain quality. However this year, I’m getting a lot of calls from homeowners saying the squirrels are damaging Satsuma on the tree.                

A gardener had a question regarding sooty mold on gardenias. The question: “Since sooty mold is the result of sucking insects — in this case white flies producing honeydew that falls on the leaves giving rise to sooty mold growth—what is an effective material to control the whiteflies without harming butterflies, hummingbirds or lizards?”                 

Sooty mold grows on a variety of ornamental plants in home landscapes; it is non-parasitic and does not penetrate the plant tissue. Sooty mold does, however, prevent sunlight from reaching the leaves thus interfering with photosynthesis. It is a result of sucking insects, such as aphids, mealy bugs, scale and whiteflies, secreting honeydew. Horticultural oils are effective and non–toxic. These kill insects by coating and suffocating them. In this process, it is important to coat the surface and undersides of the leaves. Make three applications, carefully following rates and intervals on the label. It is generally recommended that treating every 10 – 14 days is effective. Also, horticultural oils do not leave behind any toxic residues that would negatively impact butterflies, hummingbirds or lizards. Happy Gardening!!  
                                
Gerald P. Roberts  Horticulturist/Master Gardener Program Coordinator 
LSU AgCenter,                                                                  
1010 Lafayette Street, Suite 325,
Lafayette, LA 70501                                                                                                    GRoberts@agcenter.lsu.edu, Office (337) 291-7090, Fax (337) 291-7099


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November 2015

11/3/2015

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Fall is an exciting time of year for gardeners as temperature turn mild and gardening is much less of a chore compared to when day time temperatures are hot. As we progress into fall and warm season bedding plants which added color to our landscapes during warmer months begin to fade, it becomes time to start making plans to add plants to our gardens and landscapes to provide color during the fall, winter and spring months. This was a highly unusual year for many plants in our landscapes because of the rainy weather pattern in the spring followed by drought and above average temperature during the summer. Root rots were a problem I encountered and discussed with numerous gardeners this growing season, including problems which occurred with shrubs, trees, bedding plants and lawns. As a result, many of the plants in landscapes never reached their full potential nor performed as well as they had in previous years.

Many gardeners told me that they had to provide extra care to plants in order to help plants that were stressed from our previously mentioned weather patterns in spring and summer. Fortunately for gardeners as the seasons go and come we have great opportunities to add exciting plants to our gardens. Fall presents a great opportunity to plant! There was a time when it was a normal practice to wait until the spring to plant cool season bedding plants in our gardens. However we now know that planting in fall, as evidenced by numerous AgCenter trials of cool season bedding plants, trees, and shrubs, we know that fall planting provides several benefits or advantages over spring planted bedding plants. Planting shrubs, trees, and cool season bedding plants in the period from mid – October to mid – December provides plants the time to establish very strong root systems which means more healthy plants that will out perform those planted in the spring. So actually we get a better investment by enjoying color in our gardens in the fall, winter, and exploding into a spectacular display in the spring. Now is the time to plant cool season bedding plants such as pansies, dianthus, foxgloves, snapdragons, violas, just to name a few.

For bedding plants, good bed preparation is very important because it can directly impact plant performance. It is important to first remove all existing weeds, till or turn the bed to a depth of at least 8 inches, then spread a layer of organic matter such as compost, peat moss or aged manure. Next, sprinkle an all purpose fertilizer and then thoroughly mix or till all these materials, smooth the bed, and then transplant, being careful not to plant too deeply which can lead to crown or stem rot. Plant no deeper than the plant was growing in the cell pack or pot.

Once transplants are in the soil, then lightly sprinkle a weed preventer such as Preen Garden Weed Preventer or Miracle Gro Shake & Feed Plus Weed Preventer. Either one of these will suppress the germination of weeds in the flower bed. Once the weed preventer is sprinkled on the surface, moderately water the beds to settle the soil around the transplants, and firm of the soil in the bed. At this point all that is left to do is add mulch. The benefits of mulching are further suppressing of weeds, conservation of moisture, lessens soil compaction, and adding some freeze protection, and also as the mulch breaks down, it adds nutrients to the soil and helps to improve the soil structure making it better for root system expansion and plant growth. Conservation of moisture is very important to root establishment which is a priority with all newly planted plants including bedding plants, shrubs or trees.
Some of the Louisiana Super Plants for cool season planting are Sorbet Violas, Amazon Dianthus, Foxglove Camelot Series, ornamental kale, and ornamental cabbage. Some of the other Louisiana Super Plants for consideration and planting this fall are Shoal Creek Vitex, Evergreen Sweetbay Magnolia, Willow Oak, and Southern Sugar Maple.

Finally I’d like to mention a Louisiana Super Plant released this fall. Although this is not a new plant, it does perform well in our southern gardens. This plant is Homestead Purple Verbena, which is classified as a hardy perennial across Louisiana. It can be planted in mid-fall or late winter, or early spring. For best performance it should be planted in full to partial sun in well drained soil. It grows an average of 10-12 inches tall and 18-24 inches wide producing numerous clusters of deep purple flowers. It has a long blooming season usually running from later winter through early summer and into the fall months. Its flowers are rich in nectar and attract butterflies and bees. Deadheading enhances flowering and it is considered low maintenance.

Remember all Louisiana Super Plants are University Tested and Industry Approved!!
HAPPY GARDENING!

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September 2015

8/27/2015

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  As we approach the end of summer, we can begin to look forward to progressively cooler temperatures as we prepare for many fall gardening chores. I must admit that this has been a tough year so far for gardeners,  but even tougher on plants. If you can recall coming out of the winter and into spring it began to rain and the pattern continued through spring into early summer.  The rain finally subsided, then it seemed to come to a complete halt with most parts of Acadiana gradually experiencing a moderate drought. To top that off, we had above-average temperatures with several days approaching or at one hundred degrees or above.

Combine the actual temperature with the heat index and outdoor chores, including gardening, became downright dangerous with heat advisories leading many weather forecasts. Dan Gill, as a part of his presentation on botany to the new MG Class of 2015, talked about USDA Zones for heat and cold, saying that for many years most Louisiana gardeners primarily paid attention to the cold hardiness zones. Dan pointed out that as gardeners become more educated about weather patterns and how heat impacts plants in the landscape, more attention is being paid to USDA heat zones. He also emphasized that as gardeners we need to focus our attention to the growing conditions plants need to perform, and less on where we want to put plants or what we want them to do. We must not forget that plants have been genetically programmed to require growing conditions and perform like their ancestors. For example, we cannot expect a plant that requires shady growing conditions to survive in full afternoon or western sun.  The stress from heat directly impacts plant performances and when compounded by drought conditions, plants can be injured or killed. During the month of July, and so far into August, I’ve seen more trees and shrubs suffering from die back, defoliation, and death than I’ve seen in several years. It appears to me a lot of the damage began in the spring with above average rainfall resulting in saturated soils, depriving roots of oxygen, and making roots more susceptible to root rot.  Instead of plants being able to recover, they were then exposed to drought conditions and above-average day time temperatures, leading to further stress and decline. Most gardeners are looking forward to fall gardening with the hopes that cooler temperatures and timely rainfall will result in more pleasant working conditions and better plant performances.

On my visits to address the various landscape issues with plants,  I’m noticing that many of the plant beds have settled and mulches have decayed and thinned over the summer.  Topping the beds with bed builder and adding additional mulch should be included in the list of fall gardening chores. Replenish mulch layers with fresh material to maintain approximately a 2-3 inch thickness in beds. Ideally many people will mulch with what they can get their hands on for free such as leaves or pine straw. If you prefer the look of purchased mulch, put down an inch or two of leaves or pine straw, then top it off with an inch of your favorite purchased mulch. This can save money and still give you the look you desire.
Pecan trees tend to be alternate bearers,  that is producing a heavy crop every other year. Pecan trees have relatively brittle wood, having branches that can sometimes break without warning. Pecan trees that are loaded with a heavy crop are prone to limb breakage especially during rain and thunderstorms with gusty winds. Although it is disheartening to see a large branch fall from a pecan tree, there is not much that can be done.  It’s important to water pecan trees slowly and deeply during this month if it is dry. This will help the nuts finish filling out and also minimize nut drop.   

The hurricane season will be kicking into high gear this month. This is the time of the year where you should be evaluating the overall health of shade trees, and prune if needed or remove dead or broken branches. Additionally, if there are dead trees or partially dead trees in the home landscape that threaten a structure, they should be removed.
Chinch bugs can remain active in lawns at this time of year. Look for dead, tan, straw colored areas in the lawn, particularly those areas located in dry sunny areas next to concrete driveways or sidewalks. Generally these areas will get noticeably bigger and these sucking insects move into healthier greener grass which enlarges the area. These areas can be treated with Talstar, Bifenthrin, or Orthene (acephate). It’s very important that label directions on pesticides are read and followed carefully.

From now on don’t apply any fertilizer containing nitrogen to home lawns. Fertilizing lawns with nitrogen containing fertilizer this late in the year can lead to lush green growth that can increase the problems with a fungus disease called brown patch or large patch. Additionally, nitrogen can slow the grass from going dormant leading to winter injury or winter kill.  If you choose to winterize your lawn, the only nutrient applied should be potash. Any winterizing fertilizer containing moderate to high nitrogen should be avoided.   

No pruning should be done on spring flowering shrubs such as gardenias, hydrangeas, sasanquas, and azaleas because they’ve already formed their flower buds and pruning now will reduce the quantity of future blooms.

If you have areas of Virginia Buttonweed in your lawn,  as we move into the fall and it approaches maturity, pull as much of it as you can being sure to remove as much of the plant containing seeds as you can. Place all the old plants that you pull up in a garbage bad and discard.  This will help to reduce the numbers of seeds that will germinate in your lawn next spring.



Evaluate caladiums - when the plants begin to look less attractive, and two thirds of the leaves have fallen over, it time to dig the tubers. Caladiums may return next year if left in the ground, but it’s more reliable to dig them and store them indoors over the winter months. Dig the tubers carefully to minimize bruising leaving the foliage attached. Spread them out in a well ventilated area to dry. When the foliage is dry and brown, remove foliage and store tubers in paper or net bags indoors.

Happy Gardening!!  Gerald P. Roberts  
Horticulturist/Master Gardener Program Coordinator 
LSU AgCenter 1010 Lafayette Street, Suite 325 Lafayette, LA 70501 GRoberts@agcenter.lsu.edu Office (337) 291-7090 Fax (337) 291-7099  

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August 2015

7/28/2015

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As we consider making decisions about plant selections for our home gardens, we normally consider cold hardiness or cold tolerance, disease resistance, and insect resistance. Increasingly it’s becoming important that we consider heat and drought tolerance, both of which can directly impact success with plants in home landscapes when our weather pattern turns hot and dry. This is something that we cannot escape dealing with because it is a fact of life here in the deep South.

Even though LSU AgCenter horticulturist recommends several species of plants that will perform under our stressful summer and fall growing conditions, I’d like to focus on a group that performs great and continues to perform well in AgCenter plant trials. That is the Profusion series of zinnias, with hybrids representing a cross between the old cut flower type zinnias and the Mexican narrow leaf zinnias, producing flowers and foliage that are smaller than the old cut flower type but larger than the narrow leaf zinnias. They are available in five colors: Profusion white, orange, cherry, with Profusion fire and apricot having the most colorful flowers in the series and are among the best performers. These zinnias are popular among both home gardeners and landscape professionals because of overall performance including attracting butterflies, resistance to pest, and once again heat and drought tolerance. They perform very well with limited irrigation and thriving under hot dry conditions. Planting dates usually begin in mid – late April or May and may extend into the summer months. A late summer planting will ensure a strong crop of flowers into the fall primarily in September and October blooming until the first killing frost. Profusion zinnias benefit from deadheading – removing the old flowers which encourages the production of more flower buds leading to more continuous blooming.  

When chinch bugs affect lawns, specifically St Augustine, grass becomes pronounced when weather conditions become hot and dry especially during the summer months. I’ve looked at several St Augustine lawns where the home owner was concerned about areas of their lawn where the grass was turning straw colored  and dying in an increasingly expanding irregular circle. Usually at this time of the year, I know because of information from LSU AgCenter horticulturists and past experience, that chinch bug is most likely the issue. If you suspect a chinch bug problem, there is a test that you can perform in the lawn to confirm. Take about a gallon of water mix in 2 – 3 ounces of lemon scented liquid dishwashing detergent and pour in the transition area on the outer perimeter of the circle where the brown and straw colored grass meets the green grass. Wait a few minutes and if chinch bugs are present you will see them crawling around on the stolons and leaf blades of the grass. The most likely areas for chinch bugs is a lawn in sunny areas between the sidewalk and street or along driveways. As  soon as I notice lawns dying close to these areas I suspect chinch bugs since they like areas where the temperatures are the highest and these are the areas that absorb the most heat. There are several insecticide labeled for chinch bug control in lawns including bifenthrin, acephate, permethrin, malathion and cyfluthrin. The longer chinch bugs infestations are allowed to continue in a lawn the more likely it is that they will kill grass. I’ve seen several situations where the damage was so severe that the homeowner had to sod the area to replace dead St Augustine grass.  

I’m getting numerous calls from homeowners reporting serious defoliation of crape myrtles with the leaves being yellow to reddish in color. This is the result of serious infection from a foliage disease called cercospora leaf spot , which is a fungus disease that attacks crape myrtles especially during high moisture conditions like we had in mid-spring and very early summer.

Happy Gardening!!  

Gerald P. Roberts Horticulturist/Master Gardener Program Coordinator
LSU AgCenter 1010 Lafayette Street, Suite 325 Lafayette, LA 70501 GRoberts@agcenter.lsu.edu Office (337) 291-7090 Fax (337) 291-7099
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June 2015

6/2/2015

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By now most of us are keenly aware of how this rainy weather pattern has caused havoc with gardeners in south Louisiana. Numerous calls that I’m receiving are about problems related to the abundance of moisture that is directly impacting plants in landscapes and gardens. The primary problems are either fungus diseases on the leaves of plants or root rot issues – both of which leads to defoliation or death of shrubs, trees and bedding plants.

Most of the questions involve whether or not anything can be done to address these problems, and my response is always that we need to hope for improved weather conditions. When conditions are favorable for pathogens to become active or once infection takes place, we are limited in what we can do. Applying fungicides in the middle of consistent rainfall is an uphill battle. Additionally it must be understood that leaves that are damaged by fungal infections will not be repaired with the addition of fungicides. Also once a plant suffers root rot, full recovery rarely occurs.  Fungicides can slow down and protect undamaged tissue from further infection but these cannot guarantee prevention, especially when conditions are favorable for disease development. 

Weed problems in lawns are at an all-time high, especially in lawns where drainage is less than ideal or in areas that received an abundance of rainfall. To control broadleaf weeds in lawns is normally as simple as applying a herbicide that controls broadleaf weeds. If you can recall some of my previous horticulture articles, I cautioned against applying broadleaf herbicides such as Weed B Gon or Weed Free Zone. Both contain a small percentage of 2,4-D. Both are effective, but when temperatures rise into the high 80’s or 90’s, lawn grass yellowing can rise to unacceptable levels.  For broadleaf weed control at this time of the year and with temperatures on the rise, you can apply MSM Turf at the rate of ¼ teaspoon for every two gallons of water (or 1/8 teaspoon per gallon of water), evaluate and repeat in six weeks if needed.

There is a big problem now with dollar weed in lawns primarily because dollar weed favors high moisture and once again we have had our share of rainfall this spring.  I need to warn Master Gardeners regarding an issue that has occurred with the application of Scotts Bonus S Southern Weed & Feed 4 on Centipede lawns. Based on Centipede lawns that I’ve gotten calls about and what Dr. Ron Strahan has seen, there have been serious injuries and death to Centipede lawns treated with this product, especially in early spring. For this reason, Scotts has pulled the product label for the Scotts Bonus S Southern Weed & Feed 4 with Metsulfuron on Centipede lawns.  The older formulation of Scott’s Weed & Feed contained atrazine – not metsulfuron. Don’t apply the Scotts Bonus S Southern Weed & Feed 4 on Centipede lawns. There are no issues with St Augustine lawns or Bermuda Grass lawns, but there have been issues with Centipede lawns. If you or someone you know applied this product to a Centipede lawn and experienced injury or death, contact Scotts’ customer service hot line and report the problem. 

Problems with crawfish holes and chimneys in lawns have surfaced again this spring. Because of the abundant rainfall, there seems to be more than usual. Many homeowners feel that dirt chimneys interfere with mowing and will dull the blade of lawn mowers. These homeowners are calling and asking for recommendations. There is no pesticide labeled for crawfish control in home lawns. That said, how do we get rid of them? Putting pesticides down holes/burrows can potentially contaminate ground water, plus it’s illegal. Pouring bleach down burrows/holes is often ineffective.  According to Dr. Greg Lutz, Professor of Aquaculture with the LSU AgCenter, lye seems to work. Putting about a tablespoon full of lye usually does the job. As the lye migrates through the surrounding soil, it turns into harmless by products. BE FOREWARNED: lye is caustic, so wear hand and eye protection when applying.  

I received a call from someone asking me why their agapanthus was not blooming  or blooming very little. I contacted Dan Gill and Dan expressed the following opinion:  If an agapanthus has bloomed very lightly for years, it is probably doing all it can under  the conditions it is growing. It is likely just the way that agapanthus will bloom in that  location. Flowering habits can but don’t normally change patterns following several  years of flowering a certain way. Many people think that their agapanthus should bloom  more or would like them to bloom more.  Agapanthus plants will produce a certain  number of flowers regardless of our wishes. All we can do is give them appropriate care,  and enjoy the flowers they provide.  White is a color sometimes seen in agapanthus, although blue types are more popular.  Occasionally a white agapanthus will show up in a planting of blue ones. This likely  occurred during potting up by the grower or indicates a spontaneous mutation, or the  possibility that a seed falling to the soil has a plant genetically different from the parents  (white, for instance, instead of blue).  The dark bloom varieties, like Ellamae, tend to  bloom later than the light blue types. That could be a reason why a clump may not be  blooming now. Another possible reason is if they’re growing in too much shade,, or the variety  or if they were divided when the clumps were small in size. I usually tell  people not to give up  until the end of June. This is the very beginning of the blooming season,  and some varieties bloom later than others.    

I am also getting many calls on small insects congregating in groups on smooth bark trees like crape myrtles. Many of the calls refer to webbing association with these insects. These are bark lice which are scavenger insects that are harmless to trees, so there is no reason to apply an insecticide. 

Gerald P. Roberts Horticulturist/Master Gardener Program Coordinator LSU AgCenter 1010 Lafayette Street, Suite 325 Lafayette, LA 70501 GRoberts@agcenter.lsu.edu Office (337) 291-7090 Fax (337) 291-7099  
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May, 2015

5/1/2015

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By the time you get this newsletter I hope the rain has subsided and normal gardening activities have resumed. Once again Mother Nature is giving us just another example of why we are not in charge. I’ve received numerous calls from gardeners talking about problems that are a direct result of the abundance of rain we’ve received this spring.

If you recall in last month’s article I briefly mentioned brown patch disease and weed control in home lawns. Well with the additional rainfall following the publication of last month’s article, be prepared for brown patch disease problems in home lawns, especially those areas of the lawn that may not be well drained or those areas that receive poor air circulation such as an enclosed yard or areas in the shade. Additionally, be prepared to aggressively control broadleaf weeds which will continue to thrive with the abundance of moisture. Brown patch will appear as an irregular circle of dead or dying grass. Also remember to not wait to control broadleaf weeds which should be done before daytime temperatures reach the high 80’s or 90’s.

Lawn grass injury will occur with the application of either of the common homeowner herbicides such as Ortho Weed B Gon or Fertilome’s Weed Free Zone when daytime temperatures are consistently above 87 degrees. Once daytime temperatures consistently reach 87 degrees or above, broadleaf weed control should consist of MSM Turf or Celsius both of which are effective in controlling broadleaf weeds while greatly lowering the risk of turf injure due to high temperatures.  

The popularity of home vegetable gardens has given rise to more gardeners who deal with fungus disease problems especially during and following rainy weather patterns. One of these is a fungus disease called “Southern Blight.” Tomatoes and peppers are two of the most popular crops affected by Southern Blight or sometimes referred to as Southern Wilt.. During periods of high moisture plants begin to wilt and die. If plants begin to wilt, look for a white cottony type growth near the stem of the plants at or just above the soil line. Additionally there may be small tan or brown round structures resembling mustard seeds, which are the fruiting bodies of the disease. If that is the case, then, pull those plants and eliminate them. Don’t plant similar plants in that spot, instead turn the soil over and bury the area around the infected plants six-to-eight inches deep. Consider planting a grass type crop like sweet corn in that area next year.

There are no fungicides to address the problem once the infection is established, and under high moisture conditions it’s debatable if a preventative fungicide is effective. Many older gardeners at transplanting will protect the lower stems of tomatoes and peppers by wrapping a three-to-four inch wide strip of aluminum foil on the stem of peppers and tomatoes as a physical barrier to prevent infection. Typically since Southern wilt infects the lower stem at or just below the soil line, the aluminum foil is wrapped where one inch extends below the soil line and two inches above the soil line. This appears to be effective in decreasing infection.  

Because of the wet cool conditions we’ve been experiencing, expect to see the leaves of several species of oaks become infected with oak leaf blister. While all species of oaks are susceptible and can be severely infected, live oaks are the least affected. Early symptoms resemble bright green spot which can cause leaf curl and defoliation. As the infection ages the spots become tan and eventually brown. While no permanent damage occurs to the tree as a result of oak leaf blister it can be very unsightly and alarming to gardeners. Even though there are fungicides labeled to control oak leaf blister it is not practical for a couple of reasons. One of which is by the time visual symptoms occur the infections have already taken place. The second reason is it is not practical for homeowners to invest in the equipment necessary to spray large trees. The trees usually recover without any permanent damage.  

Every spring I get calls from gardeners who ask me if there are any herbicides labeled or effective to control grassy weeds in St Augustine or Centipede lawns. Remember we’ve talked in the past about controlling broadleaf weeds in lawns but grassy weeds are a different story. Controlling broadleaf weeds in lawns are easier than controlling grassy weeds in lawns. There is a wider selection of herbicides labeled to control broadleaf weeds in lawns than there are herbicides to control grassy weeds in lawn. There is only one herbicide that is available to homeowners that will give control of any grass in St Augustine grass, which is called MSM Turf, yes the same MSM Turf that can been applied to lawn grasses once the temperatures reaches the high 80’s and into the 90’s without injury to the lawn grass. This is the same MSM turf that is also effective in controlling broadleaf weeds, but it also controls Bahia grass in St Augustine lawns if Bahia grass is a problem. However, for Centipede lawns there is a better option for controlling grassy weeds, such as any herbicide containing “sethoxydim” the brand name is “Vantage” or “Poast”, which will be effective controlling grasses in Centipede lawns.  

Sedges can also be a problem in landscape beds and lawn grasses, both purple and yellow nutsedge (which is also commonly called coco grass or nut grass , but they’re not grasses, they are sedges). There is a herbicide called Sedgehammer, with the active ingredient “Halosulfuron” which is very effective on both yellow and purple nutsedge!! It can be applied to landscape beds containing established woody ornamentals. It is applied directly to the nutsedge avoiding contact with woody ornamentals leaves or stems. It is not labeled for annual flower beds!!! It can also be applied to established lawns to control sedges!!   To control grasses in landscape or flower beds fortunately there are a couple of very effective grass herbicides, one is Sethoxydim also called Poast, and Fluazifop also called Grass B Gon. There may be other brand names available but as long as the active ingredient is Sethoxydim or Fluazifop it will be effective. These herbicides will control grasses only, not broadleaf weeds.  

Because this has been a wet spring, I know weed problems are going to be a problem. I tried to provide information which will allow you to make decisions not only in your gardens but also in advising others. It must always be emphasized that it is very important to read the label and follow directions before using any Pesticide!! It is not only about safety (protecting yourself, others, pets, and the environment), but also about following recommended rates to increase effectiveness and avoid injury to desirable plants.  

Remember “The Label is the Law!” 

Happy Gardening!!
Gerald P. Roberts Horticulturist/Master Gardener Program Coordinator
LSU AgCenter, 1010 Lafayette Street, Suite 325, Lafayette, LA 70501 GRoberts@agcenter.lsu.edu Office (337) 291-7090 / Fax (337) 291-7099
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    Gerald Roberts

    Horticulturist/Master Gardener Program Coordinator
    LSU AgCenter
    1010 Lafayette St., Suite 325
    Lafayette, LA 70501
    GRoberts@agcenter.lsu.edu
    Office (337) 291-7090
    Fax (337) 291-7099

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