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- Northwest - Fall 2020
Mark Wilson, Singh, Raghuwinder, Strahan, Ronald E., Stockton, Gary A., Fontenot, Kathryn, Fields, Jeb S., Kirk-Ballard, Heather
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The LSU AgCenter Soil Testing and Plant Analysis Laboratory is the only laboratory that incorporates the latest Louisiana-specific soil fertility research in its recommendations system. Kits include directions for gathering soil samples, a soil test request form, a sealable plastic bag and a pre-addressed, postage-paid box.
www.lsuagcenter.com/soiltestingkits
Pecan (Carya illinoinensis) variety Candy. Photo by Tom Pope
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One of the wonderful things about fall is the dropping of pecans. This starts in early September and continues through November, depending on the variety. Pecan harvest can be broken down into three steps with a few simple and timely things that can be done to help get the most of the pecan harvest.
The first step is to determine when the pecans will fall. If the drop dates from the previous year are not available to you, then simply observe the trees. Preparations for harvest should be done before the pecans begin to fall. The nuts will fall between September and November. It is important to verify the pecan trees in question have nuts worth the effort before doing any prep work. Some pecan trees will produce low-quality nuts. This could be because of the genetics of the tree, a poor growing and pollination season, or low soil quality and nutrition. The nutrition of the soil can be aided by the application of fertilizer. For more information on fertilizing, see the LSU AgCenter publication Homeowner’s Guide for Fertilizing Pecan Trees in Louisiana (publication No. 2074). If the tree appears to have both a good quality and quantity of pecans, then the next step is to watch for the husks to split. Once the husks start to split, it’s time for the physical preparation.
This is the start of the second step, the prep work and harvest. These preparations can include clearing the area under the tree of debris or cutting the grass one more time to ease in pecan pickup. Blowing or raking leaves out of the area, while not needed, can help if you are not harvesting by hand. Picking up pecans as they fall is important, as wet weather can be detrimental to the nut quality. Furthermore, the more pecans that lie on the ground, the more likely wildlife will find the area, and that would be detrimental to the quantity. Squirrels, raccoons, deer and other wildlife will be happy to feed on the pecans left behind.
While it is hard not to sit down and crack open the pecans as they are being harvested, there is still one more step. The third and final step is sorting and storage. Once the pecans have been harvested, sort out the deformed or damaged nuts. Just like the saying, “One bad apple can spoil the bunch,” the same is true with pecans. Once the pecans are sorted, store them in a loose cloth sack in a cool and dry place for several weeks. This can improve the quality of the nut as it cures. Skipping this curing stage can make the nuts not crack properly and will make them more difficult to shell.
For more helpful homeowner pecan information, contact your local LSU AgCenter extension agent or look online at: https://www.lsuagcenter.com/topics/crops/pecans.
Soon we will start seeing signs that say, “It’s time to winterize your lawn.” In reality, the sign should read, “Take a soil sample to see if you really need to winterize your lawn.” We need to remember that just because the sign says to do something, that it doesn’t mean that it’s accurate.
The main nutrient in a fertilizer for winterizing your lawn is potassium. Potassium seems to enhance cold tolerance in summer lawns and reduces harm from damaging frosts. Be aware that an excessively high rate of potassium fertilizer can cause foliar burn or may compete with other nutrients for uptake. Excessive potassium is especially known to affect how much magnesium is taken up by turfgrass, which will result in a lighter-green turf color. Always apply granular fertilizers onto dry foliage to reduce the likelihood of salt burn.
If selecting a winterizer fertilizer containing nitrogen, be sure that the nitrogen content is low compared to the potassium, which is represented by the third number in the analysis. This will allow you to apply appropriate amounts of potassium without applying excessive amounts of nitrogen. When too much nitrogen is applied too late and too heavily to warm-season turfgrass, nitrogen fertilizer will promote shoot growth at the same time the plant’s metabolism is slowing. This results in a depletion of carbohydrates and stress on the plant. The new, tender shoots are also less tolerant of cold temperatures. Furthermore, the additional nitrogen will be available to cool-season weeds and may increase the incidence of large patch disease, which is prevalent in the fall.
The only way to truly know if you need to apply a winterizer is to have a soil analysis done on a sample of your soil to see what the potassium content of your soil is. If the content is low, you may need to winterize. If the content is optimal to high, then you may actually cause more harm than good by putting out a winterizer. Typically, when potassium levels require winterizing, I don’t recommend more than 1 pound of potash per 1,000 square feet of lawn.
Soil tests are simple to collect and are reasonably priced to have the analysis run. If you believe that winterizing may be for you, give me a call and let me get you the forms and mailing boxes so that you can have a test done before doing something that may not be needed at all.
Please contact me for more information at the LSU AgCenter in Lincoln Parish at 318-251-5134.
Gary Stockton
County Agent, Bienville, Jackson and Lincoln Parishes
In the fall, October is traditionally one of the driest months in Louisiana. Turfgrass and lawns will suffer in the drought and heat with weeds, insects and diseases jumping at the opportunity to bring a weakened plant down.
How do plants combat a shortage of water coupled with temperatures approaching 100 degrees? Plants’ first line of defense is closing pores on the leaves and stems, preventing further water loss, followed by wilting. Eventually, plants drop their leaves in an effort to survive and go into dormancy to conserve everything they have. Ultimately, with no relief, some plants will die.
There are things we can do to help. First, select plants that can tolerate drought. Plants differ in their use and requirements for water. Some are tougher than others. Succulent plants, especially sedums, cactus, yuccas, aloe vera, crown of thorns and kalanchoe plants are some great examples.
Unlike turfgrasses, ornamental native grasses are great drought-tolerant plants. Mostly grown for beautiful foliage, many display gorgeous flower spikes called plumes. Some commonly used ornamental grasses for Louisiana landscapes are zebra grass (Miscanthus sinensis Zebrinus); pampas grass (Cortaderia selloana); fireworks fountain grass, (Pennisetum setaceum Fireworks), which is a Louisiana Super Plant; pink muhly grass (Muhlenbergia capillaris); and panic grass or switchgrass (Panicum virgatum).
In general, many native plants tend to be the most drought-tolerant plants for the landscape because they are adapted to our climate. No one can predict just how long droughts and heat will occur. So, we can plan and plant for just this occasion. If things continue as they are and climate change occurs, we will continue to see swings in temperatures coupled with decreased water availability in the years to come.
Choosing drought-tolerant plants and native plants is a good place to start. Where you plant them is also important. Plants that are growing under the canopy of a large tree are the first to wilt because they are no match for the extensive root system of trees, so avoid planting there. Turfgrasses tend to especially suffer.
Incorporate organic matter into your soil, use mulch, weed regularly, and supplement with additional water during droughts to help. The best time to water during a drought and hot weather is the early morning and late evening to help prevent evaporation and allow the plants several hours without sun to take up the water into their system. Infrequent but deep water is best. Use soaker hoses or drip irrigation for watering.
Dr. Heather Kirk-Ballard
Assistant Professor of Consumer Horticulture
Pink muhly grass. Photo by Allen Owings.
As crazy as this may sound, preparation for the fall garden begins in August. Yes, in sticky, hot, miserable August, we can start dreaming of cool-season crops. A few vegetable seeds can be planted into trays for later planting, and the ground needs to be prepared. Check out this veggie section for a few tips on growing a wonderful fall garden.
Remove weeds completely down to the roots.
If you see transplants next to a vegetable crop, those seeds were started in August.
Plant transplants or start seed:
Beets, broccoli, Brussels sprouts, cabbage, Chinese cabbage, cauliflower, collards, lettuce, kohlrabi, kale and Swiss chard.
The crops listed next should be seeded directly into the garden:
Beets, endive, carrots, English peas, snow peas, mustard, onions (seeds, mid-to-late September), parsley, snap beans (early September), radishes, rutabaga, spinach and turnips.
Garlic toes are planted in mid-to-late September. Shallot sets can be planted all month long.
These crops can be direct-seeded or planted by transplant:
Kale, parsley, spinach, leaf lettuce, celery, Swiss chard and endive.
These crops should be direct-seeded:
Mustard, turnips, radishes, beets, onions (early to mid-October to create sets for later) and carrots.
In south Louisiana, continue to plant transplants of:
Cabbage, cauliflower, broccoli, kale and Swiss chard.
In all of Louisiana, direct-seed:
Beets, Swiss chard, spinach, kale, radishes, mustard, carrots and turnips.
Continue to plant:
Shallots and garlic in the first part of the month.
Onion seed may be planted for transplants from mid-September through mid-October. Keep the soil moist because seed coats are hard. It may take two weeks for onion seed to germinate to a stand. Some people start the onion seed directly in the garden (planting it thick) and later pull up and transplant into final spacings. Other people start their onion seed in germination mix in trays. I prefer the germination mix in trays because it is easier to plant and maintain on a bench rather than in the ground. However, I have also seen gardeners sow the onion seed directly into the row at proper spacing. But to me this is risky especially in clay soils.
Transplant the onion sets into the garden from mid-December through the end of January. Several drills of seed may be planted on one row. Leave 6 to 8 inches between drills. I like a spacing of 4 to 6 inches between bulbs.
Pay special attention to weed control in direct-seeded onions. Control winter weeds before the onset of wet soils and cool weather. Consider planting onion plants in black plastic mulch. The mulch controls weeds, enhances growth and keeps the onion bulbs cleaner. You will also need to watch out for cutworms and thrips. For the cutworms use Dipel dust or Sevin dust on the ground. Thrips can also be controlled with spinosad, neem oil or horticultural oils. You know you have thrips when you see gray discoloration on the foliage.
Fertilize plants sparingly prior to planting in the ground. This will prevent excessive growth. The thinner the set is, the more resistant it will be to bolting when the temperatures drop. If your onions begin to bolt or bloom, pinch the blooms off to continue to increase the bulb size. About 2 to 3 pounds of 0-20-20, 7-21-21 or 8-24-24 per 100 feet of row are sufficient. Side-dress onions in the spring just before they bulb. Side-dress two additional times at two- to three-week intervals.
Dr. Kathryn Fontenot
LSU AgCenter Extension Vegetable Specialist
Bulbing onions after harvest. Photo by Kiki Fontenot
The Louisiana Super Plants program identifies superior plant material for Louisiana landscapes. Louisiana Super Plants have undergone rigorous trials at multiple LSU AgCenter locations across the state of Louisiana and have been vetted and approved by the Louisiana green industry. Louisiana Super Plants are considered university tested and industry approved.
As the summer winds down, we begin to look forward to fall and all the wonderful woody plants that thrive in the landscape. We generally recommend most woody plants be planted in the fall or late winter. This allows these plants to establish roots well before our extremely hot summers. In addition, many fall landscapes highlight amazing color provided by shrubs and trees. It is a perfect time to go get some Louisiana Super Plants to enhance your landscape.
The fall of 2020 inductions include two amazing woody plants that are well known throughout Louisiana and are popular among gardeners, landscapers, nursery growers and naturalists.
American beautyberrry (Callicarpa americana) is a native woody shrub that grows throughout the state of Louisiana. They are often found in wooded areas but can be grown as specimen plants in the landscape. While sometimes considered an understory plant, American beautyberry prefers part sun or dappled shade to thrive. American beautyberry is adapted to many soils. It can thrive in moist and drier areas but prefers acidic soils. The lime green opposite-leaved foliage provides an excellent contrast to the vibrant and eye-catching purple fruit that surround the stem at leaf nodes.
While the late summer onset of fruit is often a deep purple, forms are available in a variety of attractive colors of white, pink, burgundy and more. Birds, especially songbirds, love the large berry clusters. As a result, these are the perfect plants for someone interested in attracting wildlife to the landscape as this plant will attract birds in late summer and fall while offering a marvelous pop of color. American beautyberry is a very low-maintenance landscape plant, only needing light thinning if desired. Sheering will remove the flowers and fruit. Try planting many together to create an attractive native screen or hedge. Inconspicuous flowers fill the branches in midsummer and begin to develop green berries, which ripen into the vibrant colors in late summer to early fall.
The baldcypress (Taxodium distichum) is the state tree of Louisiana and is already iconic throughout the state. These native trees are prominent and can be observed growing throughout Louisiana and the entire southeastern U.S. They do well in moist soils and flooded areas; however, they are also adapted to dry soils, allowing them to thrive in almost any Louisiana environment. Baldcypress trees thrive in very hot humid environments, with faster growth during hot growing seasons, making it a perfect fit for Louisiana summers. Baldcypress is a deciduous conifer, which means it is one of the few cone-bearing plants that loses its leaves in the fall. At maturity, a baldcypress will grow up to 50 to 70 feet tall and as much as 25 feet wide.
The baldcypress is known for attractive pyramidal shape with lacy green needles. These needles turn a wonderful rust color in the fall prior to dropping, where they provide natural mulch and serve as protection for a host of wildlife. Baldcypress provides some of the best fall color seen throughout the state of Louisiana. Additionally, baldcypress is desired for its ornamental bark. When grown in wet conditions, baldcypress will form “cypress knees,” which provide additional aesthetics for ponds. A host of aquatic, avian and ground-dwelling wildlife rely upon these trees for nesting, food and shelter throughout the year. Baldcypress makes a great addition to any landscape, natural area or public space throughout the state and provides a conceptual connection to nature and the great state of Louisiana.
For more information on Louisiana Super Plants, please contact your local LSU AgCenter extension office or visit www. LSUAgCenter.com/SuperPlants.
Dr. Jeb S. Fields
Assistant Professor and Extension Specialist
Hammond Research Station
American beautyberry
Baldcypress
Storm drain clogged by leaves and lawn debris. Photo by Heather Kirk-Ballard
Louisiana usually stays warm well into the fall, and lawns continue to grow until nighttime temperatures dip into the 50s. So be sure to mow and water your lawn, as needed, to keep it healthy.
More than likely, however, it is time to put up your fertilizer spreader. Fertilizing warm-season grasses during the fall with high nitrogen (summer-type) fertilizers or winterizing fertilizers containing high levels of nitrogen are not recommended for Deep South lawns.
Stimulating fall growth of St. Augustinegrass, centipedegrass and zoysiagrass with nitrogen leads to increased large (brown) patch disease and winter kill. Bermudagrass may be fertilized into September, but I would not make any more applications of high percentage nitrogen-containing fertilizers after late August on St. Augustinegrass, centipedegrass or zoysiagrass.
If you would like to extend the green color in home lawns this fall, apply foliar iron spray or spreadable iron granules. This will give you a nice flush of green color without increased growth.
I’m sure that you have heard of winterizer fertilizers. Potassium (the last number in the analysis on fertilizer bag) is the nutrient associated with winter hardiness and increased disease resistance with turfgrass. There is an advantage to having the correct amount of potassium in the soil. Get a soil test before applying high potassium fertilizer, however, since there is no advantage to applying excessive amounts of this nutrient. If a soil test indicates that potash is lacking, choose a potassium containing fertilizer with zero or a very low percentage of nitrogen (the first number on a fertilizer bag) during the late summer or early fall since we are not trying to stimulate growth for the reasons discussed above. If a soil test calls for adding potassium, you can apply during September while temperatures are still warm, and the lawn is still growing (very slow growth occurs as day lengths get shorter by late September and October).
An important fact to consider if you bag your lawn clippings - the removal of grass clippings from lawns can severely deplete the soil of potassium. Grass leaves and stems contain very high levels of potassium. Keep in mind that when a lawn is mowed appropriately, it is better to leave clippings to decompose on the lawn as a good source of turf nutrients, including potassium. Clippings from a lawn that is mowed regularly have only a small role in the overall buildup of thatch in turfgrass.
Fall is the best time of the year to get your soil tested by the LSU AgCenter Soil Testing Lab.
Soil testing really is the first step to a beautiful lawn next spring and is the best way to determine exactly what your lawn needs to become thick and healthy. If you haven’t tested your soil in the past several years, do it now.
To test your soil, submit a pint of soil to the LSU AgCenter Extension Service office in your parish. The pint should be a composite of soil samples collected from several different areas in the lawn. You only need to go about 4 inches deep. Also, to simplify the soil sampling and submission process, there are pre-addressed submission boxes with sampling instructions at several garden centers throughout the state. There is a small fee for testing.
The sample results will be sent to your home mailbox and email in less than two weeks. An LSU AgCenter extension agent can help you interpret the results from the soil sample. The sample results may indicate that lime is needed to increase soil pH. If so, fall/winter is a good time to apply lime, since it takes several months to activate in the soil. Elemental sulfur may be recommended to reduce soil pH in alkaline soils.
If your lawn was full of winter weeds last spring, this fall is your first opportunity to reduce infestations with pre-emergence herbicides. Pre-emergence herbicides such as prodiamine, pendimethalin, dithiopyr, isoxaben, and indaziflam may be applied in mid to late September to help manage the first flush of winter weeds like annual bluegrass, chickweed and lawn burweed. Consider reapplication in early November. These herbicides work prior to the emergence of the weeds, so timing the application before the weeds germinate is critical. Atrazine can be applied on most southern lawns for annual bluegrass and broadleaf weeds in October except for bermudagrass. Atrazine could be applied on bermudagrass after the bermudagrass is dormant. MSM (metsulfuron) can be highly effective postemergence on broadleaf weeds such as white clover and lawn burweed.
Ron Strahan Ph.D.
Associate Professor, LSU AgCenter
Annual bluegrass is the most common grass infesting winter lawns.
Lawn burweed germinates in the fall and produces painful stickers in the spring.
Wild geranium is a common winter broadleaf infesting fall lawns.
Home gardeners are often distressed by the appearance of slime molds during extended periods of overcast skies and warm and wet weather, which is very common in Louisiana.
Slime molds appear as crusty or powdery coatings on any surface, including wooden planks used for making raised beds, garden mulch, lawns or even on the leaves and stems of different kinds of plants grown in gardens.
The encrusted cover is usually a powder buildup that wipes off easily. This dusty coating may appear in different colors, like ashy gray, brown, charcoal gray, dark red, purple or bright yellow. One slime mold is named as “dog’s vomit” because of its appearance.
During favorable weather slime molds may remain in your garden or turf for a few days to more than a week.
Slime molds are nonparasitic organisms that are classified as myxomycetes, a group of free-living amoeboid protists. Slime molds feed primarily on bacteria and other microorganisms.
Slime molds’ life cycles are a bit complicated and have two different stages, an amoeboflagellate stage and a plasmodium stage. After feeding on soil microbes, fungi and organic matter, the amoeboid cells during the amoeboflagellate stage grow and multiply to form a plasmodium stage with a greasy, viscous slimy appearance.
The greasy-looking slimy plasmodium may take on one of many colors or remain clear. It creeps upward on grass leaves, low-growing plant materials and ground covers to support itself up off the ground for better spore dispersal.
The plasmodium further bunches up and develops into a fruiting or sporangium stage. This stage is the most visible and is commonly noticed in gardens and lawns.
In this elevated stage, the mature spores are released for dispersal by wind, rain or other vectors. As grass and plants dry, the sporangia dry to a crusty or dusty “crud.” Slime molds tend to reappear in the same general areas when conditions become favorable again.
Slime molds are harmless to plants and turfgrass and do not cause any diseases on them. However, if the plant tissue is heavily covered with slime mold for more than a week or so, it can shade out the plant tissue. The plant tissue may turn yellow and become susceptible to secondary disease infection.
Control of slime molds is often not needed. They start disappearing with the onset of dry weather. Slime molds can be hosed or brushed off the plant tissue but avoid hosing or brushing off during wet weather.
Gardeners who desire to remove the slime molds by hand must wear disposable gloves as spores may cause irritation to sensitive skin.
Excessive thatch buildup in lawns favors slime mold development; therefore lawns should be dethatched at regular intervals.
If chemical control is desired, contact your local extension agent to find a product that can be used to manage slime molds in landscapes, gardens and lawn turf.
For information on slime molds, please call 225-578-4562 or email rsingh@agcenter.lsu.edu.
Dr. Raj Singh
Plant Pathologist and Director of Plant Diagnostic Center
Figure 1: Slime mold at base of a tomato plant grown in a raised bed. LSU AgCenter photo
Figure 2: Slime mold growing on the leaf blades of turfgrass. Photo by Raj Singh, LSU AgCenter
Figure 3: Slime mold growing on leaf surfaces of Greek oregano. Photo by Leigh Ann Cabaniss
Figure 4: Slime mold growing on the surface of wet mulch. Photo by Andre Brock, LSU AgCenter
Horticulture Hints Fall 2020 Northwestpdf / 1.23MB