Northeast - Spring 2020

Kerry Heafner, Singh, Raghuwinder, Strahan, Ronald E., Fontenot, Kathryn, Fields, Jeb S., Kirk-Ballard, Heather

Horticulture Hints header for spring.

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Upcoming Events:

Northeast Region Spring Horticulture Forum
March 4
8:30 a.m.-noon
Thomas Scott Research and Extension Center
212 Macon Ridge Road, Winnsboro
$10 admission; lunch provided

NELA Master Gardeners Spring Plant Sale
April 3-4
West Monroe Farmers Market
1700 N. Seventh St., West Monroe

Maki Horticulture Lecture Urban and Residential Tree Care
May 6
11 a.m.-1 p.m.
Ouachita Extension Auditorium
704 Cypress St., West Monroe
$12 admission; lunch provided
RSVP by May 4

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okra flower and podjpgGet Vegetables Going in Spring

Spring is always a dicey time of year for vegetable gardens in the Northeast Region. Our last frost should be in mid-to-late March. But a cold snap even in early April can’t be ruled out. Don’t rush it if Mother Nature isn’t cooperating. A lot of gardeners plant too early and must replant when soil and air temperatures finally moderate and stabilize.

Now through May is the time to get the vegetable garden hopping! Tomatoes, peppers and eggplants can be started from seeds in early March if you didn’t get them going in February. Transplants of these nightshades can be set out in the garden in early April if the soil is adequately warmed and the weather is mild enough. Snap beans, squash and cucumbers can all be direct-seeded from mid-April through May. Cucumbers will perform best if they climb on a trellis. Fruit will stay clean and flowers will be more visible and accessible to pollinators.

Okra can be planted from mid-to-late spring, and successive plantings can be made throughout summer. Okra can be either sown directly into the garden or started in pots and transplanted. Soak seeds in water for 24 hours to soften the seed coat and facilitate germination. Transplants are ready to set out when they have the first pair of true leaves. Remember, seeds of open-pollinated varieties, like Clemson Spineless, Emerald and the so-called Cowhorn types can be saved for next year. Simply let the pods dry out on the plant and start to split open. Mature seeds will be dark-colored.

Kerry Heafner, Area Horticulturist, Morehouse, Ouachita and Union Parishes

Growing Carrots Can Be Fun and Rewarding

If you’re wondering what can be started in vegetable gardens as soon as the soil can be worked in spring, look no further than carrots! If you’re new to vegetable gardening or have simply never grown carrots, they are a guaranteed success.

No matter the variety, carrots grow best in a deeply worked soil free of rocks and debris. Several years ago, I had some growing in my raised beds at our old house at this time of year and I remember being impressed with how long the roots were able to get. That spring, I obtained two long wooden crates that were about 8 feet long and over a foot deep. With some drainage holes drilled in the bottoms, they made great planters. After topping it off with my home-brewed, sifted compost, I sowed a single row of Chantenay Red Core carrot seeds in it. After thinning and regular watering, one root was almost 6 inches in circumference at the top!

Carrot seeds are very small. Don’t sneeze when handling them. Sowing them by hand so they’re spaced evenly is tedious, and thinning clumps of newly emerged carrot seedlings is like doing brain surgery on a fly! Try sprinkling the seeds from a used salt or spice shaker. This will help make the inevitable thinning to 1 to 2 inches apart a lot less arduous. Seeds should be no more than about one-eighth inch deep, and the soil should be kept moist at all times. Seedlings should emerge in five to seven days. Before too long, you’ll see the first true leaves, which look similar to parsley. Thinning seedlings isn’t mandatory, but if the plants are to produce nice-sized taproots, they’ll need plenty of space. The depth and workability of the soil will ensure optimal root size and shape. An entire row of lush carrot foliage is impressive; it adds a nice visual texture to any vegetable garden. Aside from making sure they have adequate water, little else will need to be done to them other than the occasional shot of water-soluble fertilizer. If you’re gardening organically, coffee grounds are an excellent fertilizer for carrots, probably because of the nitrogen content. In years past, I have taken this a step further by mixing sifted compost with coffee grounds for topping the row off as the soil settles over time. Topping off the row also prevents the tops of the roots from sticking out of the ground and becoming green. Generally, the amount of lush, green foliage above ground will indicate the size of the carrot underground, so you can judge when to harvest to suit your needs. Carrots large enough for slicing will be attained if you leave them alone and let them grow. Small carrots for salads or pot roasts can be harvested sooner. Carrots are biennials, so open-pollinated varieties can be left for flowering and seed collection the second year.

Several varieties of carrot have been developed with taproots that attain different sizes and shapes, presumably a result of the types of soil they can grow best in. Imperator is the long, straight cylindrical variety found in grocery stores. Of course, its stocky build makes it a good candidate for shipping, but, frankly, these taste like cardboard compared to homegrown carrots. Other varieties such as Nantes, Danvers or Chantenay Red Core are popular varieties for the home garden. You’ll find purple, yellow, red and white carrots that are commercially available. Purple and yellow carrots are thought to have originated in Afghanistan and to have reached Europe by the 14th century. The orange carrot we know today is thought to have originated in Holland during the 17th century.

No matter which variety or color you choose, give carrots a try and see how they’ll perform for you. The rewards are sweet.

Kerry Heafner, Area Horticulturist, Morehouse, Ouachita and Union Parishes

Hand holding bunch of carrots.

Carrots can easily be grown in pots.

Carrot shown with measuring tape.

Carrots can grow well over 8 inches in length.

SuperPlantsLogojpgThe 2020 Spring Louisiana Super Plants

The Louisiana Super Plant program is an educational campaign of the LSU AgCenter that identifies superior plant material for Louisiana landscapes. Louisiana Super Plants have undergone rigorous trials and at multiple AgCenter locations across the state of Louisiana, as well as being vetted and approved by the Louisiana green industry. As such, Louisiana Super Plants are university tested and industry approved. Each year the AgCenter introduces new plants in both the spring and the fall. This year we have two amazing series of plants to announce in the spring. Both of these inductees are amazing bedding plants that will last throughout the warm season across the entire state. They are grown in full sun and bring an outstanding burst of color to any Louisiana landscape.

The first inclusion into the Louisiana Super Plants program for spring 2020 is the Lucky Star pentas. Pentas are some of the best plants for attracting pollinators to a garden, and with their bright vivid colors, pentas attract people as well! The Louisiana Super Plants program has already included Butterfly pentas, and the more compact Lucky Star pentas performed so well in our trials that it was time to add another group. Across our trialing sites and through the years, these were continually top performers. In fact, Lucky Star Dark Red was one of the top winners of 2018 in the Hammond Research Station Ornamental Trials, and Lucky Star Lavender was one of the top performers in the 2019 Hammond Research Station Ornamental Trials.

Currently, there are six different colors in the Lucky Star series, including Lipstick, White Improved, Deep Pink, Lavender, Violet and our favorite, Dark Red. These are more compact than Butterfly pentas and still keep the nonstop color throughout the season.

FlameThrower coleus is the second series that will be announced in the Spring 2020 Louisiana Super Plants. FlameThrower coleus can be spotted by their uniquely shaped foliage and their bold, lasting colors. These medium-sized coleus are great for landscape plants and also do well in large containers. Flamethrower coleus joins Henna coleus as Louisiana Super Plants. Just like with Lucky Star pentas, FlameThrower coleus performed so well across the trials that it warranted another coleus addition to the program. FlameThrower coleus thrive in full sun and do best in well drained soils. Like most coleus, FlameThrower are low maintenance landscape plants, but this series is extra special because it is one of the last to flower in the landscape. FlameThrower coleus are currently available in seven spicy varieties, including Salsa Roja, Serrano, Habanero, Chili Pepper, Chipotle, Spiced Curry and Salsa Verde.

Dr. Jeb Fields, Commercial and Ornamental Horticulture Specialist

Butterfly on plants with red flowers.
Lucky Star Dark Red pentas enticing butterfly.

Plants with lavender leaves.

Lucky Star Lavender pentas grown in containers.

Plants with red flowers.

Lucky Star Dark Red pentas grown in containers.

Plants with red and yellow leaves.

Spiced Curry FlameThrower coleus.

Plants with yellowish green leaves.

Salsa Verde FlameThrower coleus.

Plants with green and purple leaves.

Serrano FlameThrower coleus.

cucumber vinesjpgVegetable Gardening

Spring is my absolute favorite season for vegetable gardening — and I am probably not alone. Cucumbers, tomatoes, peppers and more all grow this time of year. So, let’s get started!

Before Planting:

A great garden starts with a clean garden. Pull weeds and remove any fall vegetables that have already been harvested or are harboring insects. Lightly till the soil. Then take a soil sample. The LSU AgCenter Soil and Plant Testing Lab will provide you with results of the micronutrients and macronutrients in your soil that are available to plants, the soil’s pH and organic matter content. Soil samples cost $15 and are money well spent, especially because home gardeners really only need to run samples every three or so years. Make sure the soil pH is between 5.5 and 7.0. Adding lime will increase soil pH, and adding sulfur will decrease soil pH. If you plan to incorporate manure or compost, do so before you take your soil sample. We definitely recommend adding either, but if you chose manures, make sure, they are aged at least 6 months old or older. Add fertilizer — your choice of organic or conventional — as the soil test recommends.

Planting Time:

Many great veggies can be planted in the next few months. Here are a few LSU AgCenter favorites.


Directly plant snap beans, Swiss chard, radishes, lettuce, collards, mustards, turnips, cabbage, broccoli and sweet corn seeds. Remember, sweet corn is wind-pollinated, so for full ears to grow the corn must have good nitrogen fertilization and also in stands planted three rows wide or wider. The length of the row does not matter as much as the width of the planting. You never know which way the wind will blow. Plant tomatoes, peppers and eggplant transplants mid-month in south Louisiana and later in the month for north Louisiana. Plant cantaloupes, squash, cucumbers and watermelons well after the danger of frost is over; this is usually after March 15 in south Louisiana and closer to April 1 in north Louisiana. The cucurbits can be planted from seedlings or directly seeded into the soil this month.


Plant snap bean and butter beans. Butter beans or lima beans require a little more heat to germinate and grow nicely, so April is a great month to get them growing. Radishes, collards, cucumbers, eggplants, cantaloupes, okra, Southern peas (field peas), peanuts, pumpkins, winter squash, summer squash, sweet corn, sweet potatoes (late April), tomatoes (transplants), peppers (transplants) and watermelons are also great to be planted this month. Like butter beans, okra really needs warm soil to germinate, so you may need to wait until the middle of the month or even later. If the soil is cold, the growth will be slow, and the plant will be more susceptible to insect and disease attacks. Well-fed well-watered plants planted at the right time can withstand a lot more insect and disease pressure, so patience is key for warm weather and excellent okra germination. Many gardeners also recommend soaking okra seeds for a few hours in water or scratching the surface of okra seeds with sandpaper just to help with uniform germination.

watermelons in fieldjpgMay

Most spring vegetables can be planted in May because the soil has warmed and danger of frost has passed. Plant sweet potatoes (transplants), okra, Southern peas, pumpkins, peanuts, sweet corn, watermelons, cucumbers, butter beans, squash, cantaloupes, collards and eggplants (transplants). Snap beans, butter beans, sweet corn, tomatoes and peppers (transplants) should be planted in the early days of May to prevent poor fruit set because of high temperatures. If you have not had a chance to plant tomatoes yet, you can still do so, but the LSU AgCenter recommends planting heat-set tomatoes at this time of year — especially if it is late in May. Heat-set varieties include, but are not limited to, Solar Set, Sun Gold, Phoenix and Florida 91. If the name sounds hot … it is probably heat-set. Heat-set simply means that when night temperatures are above 75 degrees Fahrenheit, pollination and fertilization will still occur.

After Planting:

Once your spring plants begin to flower, add just a little bit of extra nitrogen, such as bone meal, calcium nitrate, nitrate of soda and potassium nitrate, to the plants. Place this fertilizer about 6 inches from the main stem to prevent burning the plants. This little boost of nitrogen will help increase fruit set and increase plant vigor. How much? That really depends on which fertilizer you use. Follow rates on the label. Water your plants at the base. Plants drink from their roots and not so much from their leaves. Identify insects before you spray. Some insects are good and others are bad. There is no use in spraying the good ones and no use in spraying the bad ones with insecticides that will not work. There is not a one-size-kills-all insecticide, so make sure to talk to your local LSU AgCenter extension agent when identifying both insects and disease. Also, enjoy the garden. Yes, it’s work, but — wow — can it be pretty, too! Put a bench or little table by your garden to sit back and relax.

Dr. Kiki Fontenot, State Vegetable Extension Specialist

Checklist for Spring

  1. Treat lingering winter broadleaf weeds with herbicides containing the active ingredients atrazine, 2,4-D and mecoprop, dicamba and carfentrazone. You can also try organic alternatives with such active ingredients as citrus oil, iron HEDTA, 7.8% pelargonic acid, or clove oil and citric acid. Organic herbicides often require two applications for best control. Follow label directions for any herbicides used. Controlling winter weeds is the best practice for a healthy spring lawn.
  2. Begin your preventative rose spray program in early March. Alternate fungicides to control blackspot and powdery mildew. Treat in the early morning or late evening every week. Copper is a great organic alternative to other traditional fungicides.
  3. After spring bulbs that reliably return each year have finished flowering, wait until the foliage turns yellow before cutting it off. Food is being manufactured and stored for next year’s blooms.
  4. Mulch plants to reduce watering requirements, suppress weed growth and minimize soil temperature fluctuations. Excellent mulches are pine straw, chopped leaves and pine bark. Mulch should be applied 2 inches thick for effective weed suppression.
  5. Pull out the lawn mowers. You can make your first cutting in March. Gather and compost clippings.
  6. Fertilize your lawns if your soil tests indicate a nutrient deficiency. You can begin fertilizing after the threat of the last freeze has passed. Usually after March 15 in south Louisiana and after April 1 in north Louisiana.
  7. Fertilize shrubs in the spring using a general-purpose fertilizer such as 8-8-8, 10-10-10 or 12-12-12. Carefully follow the label directions.
  8. Plant warm-season bedding plants beginning in mid-March (south Louisiana) or mid-April (north Louisiana) and continuing through early May. The list is endless. Whether you choose annuals or perennials is a personal choice. Annuals typically live only one year if we get a rather cold winter. Perennials will come back year after year from their roots. Here is a short list of great options — celosia, coleus, cone flowers, gaillardia, hibiscus, impatiens, marigolds, pentas, ornamental peppers, vinca, black eyed-Susans, torenia, sedums and zinnias. Consult the AgCenter website at for a complete list of Louisiana Super Plants.
  9. Lace bugs on azaleas and aphids or whiteflies on gardenias are common in the spring. Treat with horticultural oils or sprays as needed as an organic option. Also examine camellias, sasanquas and hollies for scale insects on the lower foliage. Control with acephate imidacloprid or use organic alternatives such as horticultural oils sprays.
  10. To revive your cool-season flower plantings, pinch off old flowers on bedding plants after their first flower cycle is completed this spring.
  11. Roses may develop insect problems. Watch for aphids on tender new growth, thrips on flowers and cucumber beetles on foliage. Beetles are especially a problem if a vegetable garden is nearby.
  12. Spring is a great time to plant flowering trees and shrubs that will bloom in summertime. Plant these shrubs and trees (depending on the variety you select) for great flowering all summer. Some great examples are crape myrtles, butterfly bush, oleander, plumbago, hibiscus, firebush, ever-blooming roses, Encore azaleas, Shoal creek vitex and magnolias.
  13. If your crape myrtles have had problems with crape myrtle aphids and the unattractive, black sooty mold they cause, treat your trees now to prevent problems this summer. Apply a drench of imidacloprid insecticide to the base of the tree, and the tree will be protected from aphids all summer.

Dr. Heather Kirk-Ballard, Horticulture Specialist

Yellow plants in bed of pine straw.

Pine straw mulch in a bed of lantana plants

Lawn Weed Control

Herbicides can be effective tools for reducing weeds in your yard, but the best way to manage weeds is to grow a thick, healthy lawn. Lawns that are managed properly are lush and healthy, with few weed problems.

Visit and search for the keywords “lawn BMP” for more information on growing a beautiful lawn.

Pre-emergence herbicides — Weed preventer or pre-emergence herbicides can be helpful in preventing the emergence of several summer annual grasses and broadleaf weeds. Pre-emergence herbicides may be applied safely in late winter to early spring to all established southern lawns.

Most pre-emergence products for home lawns are granular and should be applied with drop or broadcast spreaders and “watered in” soon after application. These types of herbicides kill weeds as they germinate, so application timing is extremely important. You have to apply before the weeds, such as crabgrass, germinate. They will not kill any existing winter weeds.

Residents in the New Orleans area and southernmost areas of the state should apply pre-emergence herbicides in late January or early February (definitely before Valentine’s Day) and then follow up with another application in mid-April. From Alexandria to Baton Rouge, residents should apply around Feb. 10, with a follow-up application in late April. If you live in north Louisiana, try to get these herbicides applied in late February to early March, with a follow-up application by mid-May. Some pre-emergence herbicide trade names to look for are Scotts Halts, Barricade and Hi-Yield Crabgrass Preventer with Dimension. Consult product labels concerning rates and application techniques.

Post-emergence herbicides — Post-emergence herbicides are used to kill weeds that already have emerged in the lawn. Winter broadleaf weeds usually are prevalent in the late winter to early spring throughout the state. MSM Turf (metsulfuron) and Celsius (theincarbazone-methyl + dicamba + iodosulfuron) are two highly effective broadleaf-killing herbicides that have consistently performed well in LSU AgCenter evaluations on winter broadleaves. MSM is effective on wild onion, false garlic and blue-eyed grass, which is actually an iris, as well as most winter broadleaves. These are low-use-rate herbicides, especially MSM. Follow the product labels very carefully so that lawns and trees are not injured. Do not use Celsius on carpetgrass.

More widely available broadleaf weed killers include trimec-type herbicides formulated with the active ingredients 2,4-D; dicamba; and mecoprop. Some examples of trade names to look for with these active ingredients include Trimec Southern, Ortho Weed B Gon for Southern Lawns, and Ferti-lome Weed Free Zone. Product manufacturers will often recommend a follow-up spray two or three weeks after the first application. Broadleaf weed killers such as these are widely available and can be used on most southern grasses. Injury can occur, however, when using them on St. Augustinegrass and centipedegrass as the weather gets warmer in late spring.

Atrazine is a herbicide that is effective on winter broadleaves and also controls annual bluegrass, especially when applied before the annual bluegrass flowers. Most garden centers have a good supply of atrazine on their shelves. Most weed and feed products labeled for St. Augustinegrass and centipedegrass contain atrazine as their active ingredient. However, liquid atrazine sprayed on weeds in the yard has worked better in LSU AgCenter trials than atrazine weed and feed products impregnated on a fertilizer granule.

What about weed and feed products? Weed and feed herbicides can be used at the times recommended for the first fertilizer application of the year. Apply weed and feed in the New Orleans area from mid-to-late March. For north Louisiana, mid-April is the time. Just be aware that applying weed and feed too early (late February to early March) may encourage outbreaks of large patch disease.

Clean your sprayers thoroughly with an ammonia solution if the same sprayer is used for applying insecticides or fungicides on landscape plants. It is best to buy a sprayer specifically dedicated for weed killers, however, to avoid accidental injury to desirable plants. As always, be sure to read and follow product label recommendations before using any pesticide.

Fertilizing the lawn

Lawns vary in the amount of fertilizer required during the growing season. See the table below for information regarding the number and timings of fertilizer applications recommended for lawn species grown in Louisiana. Bermudagrass and St. Augustinegrass require the most fertilizer compared to other lawn grasses. Centipedegrass and zoysia only require one to two applications of fertilizer per year.


Number of fertilizer applications/year

Recommended months

Bermudagrass3March/April, June, August (optional September)
Centipedegrass1 to 1.5April and possibly June at ½ fertilizer rate
St. Augustinegrass2 to 3April, June, August
Zoysia2April and July

Which fertilizer should I use during the growing season?

A spring application of weed and feed could serve as your first fertilizer application. For future applications during the growing season, consider using 3:1:2 or 4:1:2 ratios of N-P-K as a guide for the analysis of fertilizers to choose for the lawn. For example, a fertilizer with an analysis of 21-7-14 is a fertilizer with a 3:1:2 ratio. You would be better off getting your soil tested. Soil tests would be most helpful to determine exactly what nutrients are needed to make your lawn beautiful. Contact your parish extension office concerning soil sampling your yard today.

Dr. Ron Strahan, Weed Scientist and Turfgrass Specialist

Grass shoots growing in the lawn.

Blue eyed grass is actually an iris that often infests lawns in the early spring.

Indian mock strawberry growing on lawn.

Indian mock strawberry is common in poor lawns.

Clover sprouting in the lawn.

Spotted burclover is a cool season legume found in lawns in spring.

Exobasidium Leaf Gall

Leaf gall of camellias and azaleas is a fungal disease favored by extended periods of cool, wet weather during spring. This is primarily a leaf disease, but it occasionally may occur on stems, flowers and seed pods. There are mainly two species of the Exobasidium fungus that cause this disease: Exobasidium vaccinia on azaleas and E. camelliae on camellias.

Symptoms of leaf galls start appearing soon after the plants finish flowering. Leaves are distorted and become thickened with a fleshy or leather-like texture (Figures 1 and 2). Galls tend to be pale green, pink or white (Figure 3) in the beginning, but as they develop, they become white and powdery. The white powder material is the spores of the fungus, which readily disperse via air currents and by splashing water. As the galls get older, they shrivel up, dry out and turn brown and hard (Figure 4). Older galls fall to the ground, where they survive and may serve as a source of incoculum for the next spring susceptible growth.

Management of leaf galls is achieved primarily by adopting good cultural practices in the landscapes. Proper pruning and discarding of galled leaves are very important in reducing the spread of the disease. Cut galled leaves a couple of inches below the symptoms and, before discarding them, put them in resealable clear storage bags, such as a Ziploc-style bag.

Remove and destroy affected leaves with galls that have fallen on the ground. Improve air circulation by selective thinning of the canopy of established plantings to promote rapid drying of foliage. Also, maintain adequate spacing when establishing new plantings to avoid creating favorable conditions for disease development. Fungicides may help avoid infection when applied beginning at bud break. Repeated applications may be required every 10 days as long as the conducive weather conditions persist for disease development. For fungicide selection, please consult your local LSU AgCenter extension agent. For more information on leaf galls of azaleas and camellias, please contact Dr. Raj Singh at 225-578-4562 or

Dr. Raj Singh, Plant Pathologist and Director of Plant Diagnostic Center

Camellia leaf with gall.

Figure 1. Leaf gall on a camellia (photo credit: Dr. Raj Singh, LSU AgCenter).

Azalea leaf with gall.

Figure 2. Leaf gall on an azalea (photo credit: Dr. Raj Singh, LSU AgCenter).

Three colors of gall on camellia leaves.

Figure 3. Camellia galls showing color variations (photo credit: Dr. Raj Singh, LSU AgCenter).

Brown gall on an azalea leaf.

Figure 4. Older mature gall turning brown on an azalea. (photo credit: Dr. Raj Singh, LSU AgCenter).

2/5/2020 5:04:55 PM
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