Horticulture Hints for Louisiana - Spring 2024

Heather Kirk-Ballard, Hawkins, Keith, Heafner, Kerry, Simoneaux, Mariah

Horticulture Hints for Louisiana banner for Spring 2024.

Nature’s Perfumery:
Cultivating a Garden Full of Fragrance


An image depicting Nemesia, a purple and lilac flower.
Nemesia is an excellent choice for a fragrant bedding plant that provides delicate color for spring. Photo by Randy LaBauve

Planting fragrant plants offers several benefits that enhance both the garden and the overall environment. They not only add aesthetic appeal, but fragrant plants also add another dimension to the garden with their delightful scents, enhancing the sensory experience for anyone who enters the space.

Fragrances from plants can positively affect mood and mental well-being, promote relaxation, reduce stress and uplift spirits. Fragrant plants often attract pollinators such as bees, butterflies and hummingbirds, which are essential for pollination and maintaining biodiversity in the ecosystem. Many fragrant plants can be grown indoors, bringing their delightful scents into homes and creating a pleasant atmosphere. Some fragrant plants, such as lavender and rosemary, have therapeutic properties and are used in aromatherapy for relaxation, stress relief, boosted energy and improves mood. With all those benefits, why not grow your own? Here’s a curated list of highly-scented plants that not only add fragrance to your garden but can also be cut and enjoyed indoors.



Bulbs

  • Hyacinths (Hyacinthus orientalis): Gorgeous, fragrant blooms from late winter to early spring. Chill bulbs for 13 to 16 weeks at 32 F before planting.
  • Paperwhites (Narcissus spp.): Fragrant, white blooms from late December through January. Chill bulbs for 12 to 16 weeks before planting.
  • Oriental lilies (Lilium asiatica): Late summer fragrant flowers. Plant bulbs in well-drained soil in fall.

Shrubs

  • Butterfly bush (Buddleia davidii): Large, deciduous shrub with fragrant flowers in a variety of colors. Loved by butterflies.
  • Butterfly ginger (Hedychium coronarium): Highly fragrant, pure white flowers attract butterflies from midsummer to first frost.
  • Gardenia (Gardenia jasminoides): Gardenias are well-loved for their strong, sweet fragrance and beautiful white flowers. They thrive in the warm, humid conditions of Louisiana, blooming from spring through early summer.
  • Roses: (Rosa spp.): Romantic, fragrant flowers available in numerous cultivars blooming from spring to autumn.
  • Southern sweetshrub (Calycanthus floridus): Also known as Carolina allspice, this native shrub produces maroon-red flowers with a spicy, fruity fragrance, thriving in part shade to full sun.
  • Sweet viburnum (Viburnum odoratissimum): Evergreen shrub with highly scented blossoms in spring.
  • Yesterday, today and tomorrow (Brunfelsia latifolia): Fragrant flowers that change color over three days on an evergreen shrub.

Trees

  • Banana shrub (Magnolia figo): Small, evergreen tree with banana-scented flowers blooming in spring and repeatedly throughout the year.
  • Frangipani (Plumeria spp.): Highly fragrant flowers in a variety of colors from November to April. Ideal for pots.
  • Lemon (Citrus x meyeri): Citrus-scented flowers almost year-round with mild-flavored, thin-skinned lemons.
  • Magnolia (Magnolia grandiflora): Magnolias are a staple in the South and can be used as a backdrop for a fragrant garden. The large, beautiful flowers have a strong, sweet scent.
  • Sweet olive (Osmanthus fragrans): Large, evergreen shrub or small tree with intensely fragrant white flowers in late winter and early spring.

Vines

  • Jasmine (Jasminum spp.): Various jasmine species, including star jasmine, offer sweet-smelling flowers. They can be grown as ground cover or trained up trellises.
  • White jasmine (Jasminum polyanthum): Popular fragrant flowers on glossy green leaves of a climbing vine. Requires full sun and trellising support.
  • Wisteria (Wisteria sinensis): Violet-blue clusters of sweet-smelling blooms. Can be trained into a shrub form with pruning and staking.

Bedding Plants

  • Sweet alyssum (Lobularia maritima): This low-growing plant produces small, fragrant flowers in white, purple and pink. It blooms profusely in cooler months and can tolerate a range of conditions.
    An image depicting Alyssum, a white flower.
    Snow Princess alyssum produces a cascading display of fragrant white flowers on a compact spreading habit. Photo by Allen Owings
  • Four o’clocks (Mirabilis jalapa): Named for their late afternoon blooming habit, these plants produce flowers in various colors with a strong, sweet fragrance. They are easy to grow and can even become naturalized in the garden.
  • Heliotrope (Heliotropium arborescens): Known for its vanilla-scented flowers, heliotrope blooms in clusters of purple, blue or white. It thrives in full sun and well-drained soil.
  • Nemesia (Nemesia spp.): Produces vibrant, often fragrant flowers in various colors, thriving in cool temperatures and suitable for beds, borders and containers.
  • Stock (Matthiola incana): Cool-season annual with a spicy scent. Grayish leaves complement bright colors.
    An image depicting Stock, a cottage flower that is light red and pink.
    Stock is a fragrant cottage flower commonly used in flower arrangents for their gorgeous blooms and clove-like scent. Photo by Heather Kirk-Ballard
  • Sweet peas (Lathyrus odoratus): Planted in fall, these vines produce fragrant flowers on long stems, perfect for cutting into early summer bouquets.

Herbs

  • English lavender (Lavandula spp.): Well-loved fragrance from lavender-blue flower spikes. Requires full sun and well-drained soil.
  • Lemon balm (Melissa officinalis): Mounding, herbaceous perennial with lemon-scented foliage.
  • Pineapple sage (Salvia elegans): Late summer to early fall bloomer with red flowers. It is drought tolerant once established.
  • Rosemary: (Salvia rosmarinus) Evergreen herb with highly fragrant flowers and spikey leaves, ideal for both fragrance and culinary uses.

You can enhance your garden’s allure with these aromatic delights. Whether outdoors or indoors, they are sure to captivate your senses and those of pollinators alike.

Heather Kirk-Ballard, Ph.D.
LSU AgCenter Horticulturist

Beehive Buzz: Garden Bees and Notes


Brittinie DeVille, a Master Gardener from Forest Hill, Louisiana, shared an observation in her garden.

“I was wondering if you would happen to know of what might be going on in my garden regarding some honeybees? I thought you would be the person to ask giving your bee knowledge,” she asked. “When I planted my garden I laid down a layer of straw for mulching. By the next morning, I had about 15-20 honeybees flying around the straw mulch. They crawl around in it then fly to a new spot and crawl around, on repeat. Do you have an idea on why they seem to be attracted to this straw or my garden beds suddenly?”

An image depicting a honey bee on grass and straw.
A honeybee foraging on straw mulch. Photo by Brittinie DeVille

After consulting with some beekeepers, several shared their comments.

“My thought is they are getting something out of the straw to help them make propolis, maybe? So maybe they are using straw for that purpose,” said one.

Propolis is the equivalent of “bee caulking” to seal cracks in beehives. Bees will use natural resources to make propolis.

“Looking closely [at the picture, I see] there is moisture showing on the straw,” another beekeeper said. “[It] could be as simple as a convenient watering place to carry moisture back to the hive.”

In a separate issue, another Beehive Buzz follower wanted to help native bees.

“I read your article about honeybees vs. native bees and the value of each. I just began raising honeybees as a hobby (only two hives). What can I do to improve the plight of the native bee populations?” he asked.

An image depicting a native bumblebee searching for pollen in a flower.
A native bumblebee. Photo by David Cappaert, Bugwood.org

The Xerces Society for Invertebrate Conservation, www.xerces.org, has some information on conserving wild native bees. Excerpts from their website are in quotations here:

  • Create, Restore, and Manage Habitat: “Growing the right flowers, shrubs, and trees with overlapping bloom times is the single most effective course of action to support pollinators from spring through fall.” The Xerces Society site provides guidance on planning, site preparation, installation, and maintenance.
  • Provide Access to Nesting Sites: “Nesting resources can take many forms, from natural to man-made.” The AgCenter has a publication, “Gardening and Landscaping Practices for Nesting Native Bees,” available for download at this link.
  • Managing Pests While Protecting Pollinators: “It is critical that we work simultaneously to reduce use of pesticides and to minimize the risk of pesticides to pollinators where pesticides are used.” Most pesticide labels have information on protecting pollinators in a red, diamond-shaped box. A pollinator plant list for the southeast U.S. is available at this link.
  • Pick the Right Plants: “Native plants, which are adapted to local soils and climates, are usually the best sources of food and shelter for native pollinators. Incorporating native wildflowers, shrubs, trees, vines, grasses, and more into any landscape helps a diversity of wildlife, and provides benefits to soil, water, and air quality. Additionally, most native plants can flourish in poor soils and require minimal irrigation.” The Xerces Society has a regional plant list for the southeastern United States at its website.

Trevor Rousselle, of Reserve, Louisiana, observed a green bee and correctly identified it as a female, brown-striped sweat bee. He asked for confirmation of its identity.

An image depicting a brown winged striped sweat bee resting on a yellow flower.
A brown-winged striped sweat bee. Photo by Trevor Rousselle

Victoria Bayless, curator of the Louisiana State Arthropod Museum in Baton Rouge, confirmed the ID, but with a slightly different common name – a brown-winged striped sweat bee. During Rousselle’s research, he observed that, “[It] seems like the males have bright yellow stripes whereas the females are almost entirely green with black and slightly greyish, if not white, stripes.”

This bee is a native, solitary, ground-nesting insect. It will visit flowering plants including sunflowers, asters, morningglories, pumpkins and their relatives, legumes, fringe tree, evening primroses, irises, roses and others.

The Long Leggedy Beasties blog shares this caution, “Sweat bees can sting, but generally are not particularly aggressive unless handled roughly. Stings, if they do occur, are relatively minor.”

Pam Archer, of DeRidder, Louisiana, sent in a photo and asked, “This is a new one on me. What is it? It is about the size of a bumblebee, but [it is] way off color. [It] Looks like it would sting.”

An image depicting a carpenter bee.
A carpenter bee. Photo by Pam Archer

Archer’s photo shows a carpenter bee. To tell the difference between a bumblebee and a carpenter bee, remember that a bumblebee has a “fuzzy butt,” and a carpenter bee has a “shiny hiney.”

Robert Souvestre, retired AgCenter horticulture agent, addressed Archer’s concerns about stings.

“Carpenter bees tend not to be aggressive, and the insect you see hovering around wood and sometimes getting in your face is the male protecting the nesting site,” Souvestre said. “Males do not have stingers so they cannot hurt you. The females do have stingers but seldom bother people since they are only interested in boring the wood and laying eggs.”

Souvestre also addressed the damage to wood by these insects.

“Prevent damage from carpenter bees by painting exposed wood. Though not a guaranteed remedy, it works most of the time,” he said. “A preventative treatment may be made by applying two applications of a borate formulation (Timbor) on existing structures and using pressure treated wood when rebuilding or replacing damaged wood.”

Christy Frederic, of Pineville, Louisiana, is another Master Gardener contributor to Beehive Buzz. She sent a photo with this question, “[Do you] any idea what kind of insect makes these little tunnels? I poked a pine needle in a couple, and it went in several inches easily.”

James Villegas, an LSU assistant professor, helped to identify this insect.

“Those look like nests of digger bees,” he said. “Is the homeowner seeing bees around? Digger bees are docile unless provoked.”

The Bird Watching HQ website, at www.birdwatchinghq.com/bees-in-louisiana/, shared this narrative about digger bees: “Digger bees are aptly named – to make their nests, they dig into the soil and construct their homes from mud!

“They are considered social-solitary bees. This term sounds confusing but think of it like this: Digger bees nest in the ground, in their hole. But, their nests are often near other digger bee nests, like individual houses in a neighborhood. So, digger bees might be considered the suburban settlers of the bee world!

An image depicting ground with several entrances made by digger bees hidden by leaves and other debris.
A group of digger bee entrances. Photo by Christy Frederic

“Some studies have shown digger bees are even more efficient at pollinating flowers and crops than honeybees or bumblebees. Unfortunately, because digger bees resemble wasps, people often have them killed or removed when they find them. But these species are relatively docile and will only sting if directly provoked.”

If you want to contact Beehive Buzz, please email your questions and pictures to khawkins@agcenter.lsu.edu or call 337-284-5188.

Keith Hawkins
Area Horticulture Agent

Note: Before you buy or use an insecticide product, first read the label, and strictly follow label recommendations. Mention of trade names or commercial products in this article is for informational purposes only and does not constitute endorsement by Louisiana State University AgCenter.

This work has been supported, in part, by the U.S. Department of Agriculture, National Institute of Food and Agriculture, Renewable Resources Extension Act Award, Accession Number 1011417.

Checklist for March, April, May

seasons-icons-solid.jpg thumbnail

March


  1. Vegetable garden: Repair and maintain raised beds, trellises and other garden structures during the winter. This ensures they are in good condition for the upcoming growing season. Take the opportunity to amend your soil during winter. Add compost or organic matter to improve soil fertility and structure. Conduct a soil test to determine if any specific nutrients are lacking and amend accordingly.
  2. Lawn: Minimize foot traffic on the lawn during winter to prevent compaction or damage to dormant grass.
  3. Landscape beds: Assess the performance of your annuals and perennials during the winter months. Note which plants thrived and which ones struggled and plan to adjust your planting choices for the following year if necessary.
  4. Trees and shrubs: Take the time to inspect your trees and shrubs for signs of pests or diseases. Look for pests, such as scale insects or aphids, and treat them, as necessary. Remove any diseased or infested plant material and dispose of it properly. Do not prune evergreens or spring and summer blooming shrubs. Fertilize this month if you missed it in February.
  5. Fruit: Apply fertilizer to fruiting trees that were not fertilized in winter now at the recommended rate. Early spring is an ideal time to plant both fruit trees and shrubs.


April


  1. Vegetable garden: Get your warm-season crops in the garden this month. Vegetables are heavy feeders. Supplement with a side dress of ammonium nitrate, ammonium sulfate, calcium nitrate or potassium nitrate inches from the base of the plant and water in right away.
  2. Lawn: Remove any debris, such as fallen leaves, twigs or branches, from your lawn to promote healthy growth. Gently rake the lawn to remove dead grass or thatch that may have accumulated over the winter. This helps improve air circulation and prepares the ground for new growth.
  3. Landscape beds: Get weeds under control. Make sure beds are weed free and well-mulched with an evenly distributed layer at 2-4-inch thickness. Start looking for new varieties and improved cultivars for your landscape beds. Louisiana Super Plants are excellent for landscape beds.
  4. Trees and shrubs: Apply a layer of organic mulch, such as wood chips or shredded bark, around the base of trees and shrubs. Mulching helps conserve moisture, suppress weed growth and regulate soil temperature. Ensure the mulch is spread in a thin, even layer, keeping it away from the trunk or stems to prevent moisture-related issues. Wait to prune and fertilize spring-flowering shrubs such as azaleas, camellias, viburnum and spireas after they have finished flowering.
  5. Fruit: Some plants require cross-pollination, so ensure proper pollination by attracting pollinators to your garden. Plant flowers that attract bees and other pollinating insects nearby or consider using techniques like hand pollination.


May


  1. Vegetable garden: Install stakes, trellises or cages to support climbing plants like tomatoes, cucumbers or beans. Prune plants as needed to promote air circulation and remove any diseased or damaged parts.
  2. Lawn: Address any bare or damaged spots in your lawn by loosening the soil, adding fresh topsoil if needed, and seeding or installing sod for repair.
  3. Landscape beds: Plant, plant, plant! Monitor the moisture levels in the landscape beds and provide supplemental watering as needed. Water deeply and infrequently to encourage deep root growth. Adjust watering schedules based on rainfall and the water requirements of the plants.
  4. Trees and shrubs: Assess the overall health of trees and shrubs, looking for signs of stress such as wilting, leaf discoloration or stunted growth. Investigate the underlying causes and take necessary steps to alleviate stress, such as adjusting watering schedules or addressing nutrient deficiencies.
  5. Fruit: Thin out fruits to reduce overcrowding and promote better fruit quality. Be sure plants receive enough water to ensure good production as we approach harvest season for many fruits such as blackberries, blueberries, figs and muscadines.

Heather Kirk-Ballard, Ph.D.
LSU AgCenter Horticulturist

Don’t Skip the Mulch

An image depicting a well-maintained flower bed in which yellow and pink tulips have been planted. The ground is covered by pinestraw.
Pinestraw makes a wonderful mulch. Photo by Heather Kirk-Ballard

Mulch serves many purposes in the landscape. In addition to giving planting beds a neat and uniform appearance, it reduces weed pressure, regulates soil temperature and moisture, and adds organic matter to the soil over time.

Mulch applied to flower beds, vegetable gardens and around trees and shrubs decreases pressure from unwanted weeds. Many weeds that germinate from seed will not be able to sprout under mulch. Pine straw is one of the best mulch options in Louisiana and is readily available. Wood chips, pine bark, chopped leaves, dried grass clippings and straw also work well. If you have large areas to cover, consider purchasing your mulch in bulk from a local nursery.

Mulch helps to regulate soil temperature. Plant roots are cooler in the summer and warmer in the winter when mulch is used. If you choose to use plastic mulch in the summer, select white instead of black in order to prevent plant roots from becoming too hot. Mulch maintains soil moisture by reducing evaporation. Gardeners can water less frequently, and the likelihood of soil moisture fluctuations decreases. Many vegetable plants are sensitive to soil moisture fluctuations, especially tomatoes.

Mulching to a depth of two to three inches is sufficient in most situations. When applying mulch be mindful to go out and not up. This is extremely important around trees and other woody ornamentals. Often mulch is mounded in a volcano-like pile around the base of trees. This can be very detrimental, hindering oxygen exchange to the roots and resulting in disease and decay of the trunk.

As mulch decomposes, organic matter is added to the soil, improving soil aeration, structure and drainage. There is no need to remove old mulch; simply add the new layer of mulch over the top when it is needed. If mulch becomes matted, use a rake to break it up and refresh the appearance.

For more information visit www.LSUAgCenter.com or contact Mariah Simoneaux at MJSimoneaux@agcenter.LSU.edu.

Mariah Simoneaux
Horticulture Extension Agent, Ascension Parish

Spring Gardening Guide for the Northeast Region

Spring has sprung in the Northeast Region! A lot is happening in our gardens and landscapes during March, April and May, so let’s get outside and get after it!

Lawns


Lawns will be coming out of dormancy during the spring months and will respond better if fertilizer applications start after they have come fully out of dormancy and resume growth. Winter weeds, such as hairy bittercress (Cardamine hirsuta), henbit (Lamium amplexicaule), lawn burweed (Soliva sessilis) and annual bluegrass (Poa annua), will be finishing up their life cycles by dropping seeds. Seeds of warm-season weeds, like green kyllinga (Kyllinga brevifolia), purple and yellow nutsedge (Cyperus sp.), Virginia buttonweed (Diodia virginiana) and common lespedeza (Kummerowia striata), will be germinating as soil temperatures warm up. A preemergent herbicide applied before lawns come fully out of dormancy will suppress germination of weed seeds. Products containing dithiopyr are commonly available at both locally owned garden centers and big box stores. Always carefully read, understand and follow the label directions on any pesticide container before using. The label is the law.

Spring is the perfect time to establish a new lawn in the Northeast Region before soaring summer temperatures set in. Both seeding and sodding can be done provided the area for the new lawn has been adequately prepared. This includes clearing the area of any existing vegetation, grading appropriately for drainage and preparing the soil per recommendations of a soil test. Once seed or sod has been put down, provide adequate water until the new grass is established, especially if rains are infrequent. Then, a once weekly schedule can be applied. Resist the temptation to water Deep South turfgrasses more than twice a week, even during the summer months. Deep South turfgrasses are adapted to hot, dry conditions. Excess water may lead to fungal issues.

Photo of a triangular garden box filled with young tomato and snap bean plants.
Snap beans and tomatoes. Photo by Richard Bogren

Vegetables


Spring and summer vegetable transplants should be set out in the garden as soon as all danger of frost has passed. Tomatoes, peppers and eggplants will thrive in slightly acidic, organic soil that has good drainage. Set tomato plants fairly deep and remove the lowest pair of leaves. Whether they are staked, caged or allowed to crawl along the ground on a bed of mulch is a matter of personal preference. If tomatoes are staked, put stakes into the ground prior to planting to avoid damaging the root system later. Give transplants a good drink at planting and leave enough space between plants and rows to allow good air circulation. Mulch with organic material like wheat straw, hay or dried lawn clippings (if herbicides have not been used on the lawn). Pine straw also makes a wonderful mulch in the vegetable garden. Later in the year when spring and summer crops have played out, organic mulches can be either composted or turned back into the soil. Cucurbits such as cucumbers, summer squash, and watermelons can go into the vegetable garden during these months. Try not to damage the root systems if possible. These can also be seeded directly into the garden. Both bush and vining summer squashes are available for home gardens, and persnickety gardeners have their favorites.

Seeds can be saved from all vegetable varieties that are designated as “open pollinated” or OP. Open pollinated varieties breed true. Seeds should be fully mature before they are harvested from the fruit. This means that the fruit the seeds are harvested from needs to be either fully or overly ripe. Cucumbers, for example, are not fully ripe when we typically harvest and use them. A fruit should be left on the vine until it turns yellow or orange before the seeds are harvested. Tomatoes are fully ripe when they stop getting bigger and are solid red or pink, depending on what variety is grown. For fermenting, the contents of the fruit can be squeezed or scooped out into a pint or quart jar. Then, an equal volume of water can be added, and the jar can be allowed to sit for a few days. A layer of fungus will develop across the surface, and that’s exactly what should happen. Viable seeds typically sink to the bottom of the jar while nonviable seeds float. After several days to a week, remove the layer of fungus and nonviable seeds, and rinse the good seeds in a strainer under a heavy stream of water. Dry on wax paper for several days. Seeds should be labeled and stored in an airtight container in a freezer or refrigerator.

Kerry D. Heafner
Associate Extension Agent Caldwell, Morehouse, Ouachita, Richland,
and West Carroll parishes

Marcie M. Wilson
Assistant Extension Agent
Catahoula, Concordia, East Carroll, Franklin, Madison and Tensas parishes

5/3/2024 8:51:12 PM
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