LSU AgCenter's Weekly Message

You Don’t Have to Wait for Cold Weather to Plant Some Cool-Season Vegetables

It may not feel like it right now, but we’re approaching a time of year when we can plant many of our cool-season vegetables. Some can be planted earlier and some later, but almost all can be planted between mid-September and mid-October. These include cabbage, kohlrabi, broccoli, cauliflower, Brussels sprouts, bok choy, greens (collard, kale, mustard, turnip), radishes, beets, carrots, lettuce, shallots, garlic, and green (“English”), sugar snap, and snow peas.

There are a few exceptions. Seed pieces of white (“Irish”) potatoes can be planted between August and mid-September and again in late winter, and transplants of bulb-forming onions that grow well in Louisiana should be set out between mid-December and January. Fava beans aren’t a very common crop here, but I understand that the time for sowing these is October through November.

A second sweet spot during which a lot of cool-season veggies can be planted is late January through February. Cabbage, kohlrabi, broccoli, cauliflower, greens, radishes, beets, carrots, lettuce, shallots, and white potatoes can be planted at this time. Many can be established earlier or later, too.

If you want to give the garden a rest, you might consider seeding a fall cover crop. Cover crops can be used to build up soil organic matter, take nitrogen from the air and put it in the soil (in the case of plants in the bean family, or legumes), prevent loss of nutrients from the soil during the off-season (after adding compost or manure, for example), suppress weed growth, and prevent erosion. The first half of October is a time when many cool-season cover crop species – such as cereal rye, annual ryegrass, wheat, oats, hairy vetch, and crimson clover – can be planted.

The second class in the gardening and lawn care series will take place next Tuesday, September 16, at 6 PM at the Lee Memorial Forest Main Lodge (21139 Lee Memorial Drive, Franklinton). Please join us if you’re interested! Call or email me to register or for more information. The LSU AgCenter and LSU provide equal opportunities in programs and employment.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Giant Plume Ginger and Pink Velvet Banana Offer Tropical Foliage and Pink Color

Two staples of my perennials border have a lot in common. Giant plume ginger (Curcuma elata) and pink velvet banana (Musa velutina) both grow to about 6 to 7 feet tall once they’re well-established. They have a tropical appearance and die back to the ground in the winter but, being cold hardy throughout Louisiana, return in the spring. When the plants lack flowers or fruit, it’s easy to confuse them.

What makes these two plants so appealing to me, besides how easy they are to grow, is the pink color they provide in the garden. Giant plume ginger sends up flower stalks with striking pink bracts in the spring. (The flowers themselves, less noticeable, are yellow.) They begin flowering in late April, before the plant’s leaves emerge. The pink velvet banana plant, returning after the winter, begins flowering in late spring. Many banana species have pink bracts, but as the name suggests, this plant also produces small, pink-peeled bananas.

Neither giant plume ginger nor pink velvet banana seem to be widely available in nurseries. However, both are easily propagated by division of their rhizomatous root systems or, in the case of the pink velvet banana, by seed.

Bananas need a good deal of sun exposure for maximum foliage, flower, and ornamental fruit production. Giant plume ginger is one of the more sun-tolerant gingers but probably still benefits from some afternoon shade. Soil should be reasonably well-drained.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Sometimes, Gardening is for the Birds

Birds need food, water, and shelter. Gardens can provide all of these. As we approach fall, which is generally considered the best time to plant most trees and shrubs of temperate origin (i.e., not ones that are marginally cold hardy) in Louisiana, you might consider some plants that support birds.

Many types of trees and shrubs provide shelter and nesting sites. Evergreen plants have the additional benefit of providing shelter in the winter. Including plants of various heights may help draw a greater diversity of birds.

Fruit- and seed-producing plants provide food for many types of birds. Such trees include American holly, eastern redcedar, mayhaw, parsley hawthorn, magnolias, oaks, pines, sweet gum, native plums, and wild black cherry. A fruit producer that might not be as obvious is cabbage or sabal palm.

Shrubs that produce bird food include American beautyberry, arrowwood viburnum, cultivated and native blueberries, elderberry, mulberry, various fruiting hollies, Japanese yew, and wax myrtle.

This article is largely about trees and shrubs, but many herbaceous (non-woody) plants support birds, too. Blackeyed Susan and sunflower are just a couple of many examples that could be named. They may not be at their most attractive point once they’ve finished flowering and have seedheads, but it’s at this stage that they provide food for seed-eating birds.

Hummingbirds consume flowers’ nectar. Red, pink, and orange flowers, as well as those with a tubular shape, are especially attractive to them. Some plants that entice hummingbirds are bottlebrush, red buckeye, coral honeysuckle, firebush (including Lime Sizzler, which has been named a Super Plant), cigar plants, cardinal flower, scarlet or blood sage (Salvia coccinea), and Turk’s cap.

Bottlebrush varieties vary with respect to their cold hardiness, and some are often injured in very cold winters. Woodlanders Red (AKA Woodlanders Hardy) is one of the most resilient. Bottle Pop Neon Pink bottlebrush has also performed well at the Hammond Research Station. As with root-hardy tropicals, it’s probably best to wait and plant this shrub in the spring.

Some birds consume insects, small reptiles, amphibians, or even small mammals rather than fruits, seeds, or nectar. Plants also provide habitats for these. Having some native plants in the garden helps support insects that are more likely to be the foods of choice for native birds.

The Baton Rouge Audubon Society is partnering with the LSU AgCenter Hammond Research Station for a Hummingbird Celebration on September 20, 2025, from 8 AM to 1 PM. The event will include education about and sales of plants that support hummingbirds.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Native Grapes: Muscadines and More

We regularly see muscadine grape (Vitis rotundifolia) vines in Louisiana. Their commonness and vigorous growth (often far up into trees) are signs of how well adapted they are to most parts of our state. I encourage people who are interested in growing fruit that doesn’t require a lot of work to manage diseases and insects to grow muscadines, though a sturdy trellis and attention to training and pruning are needed. Many improved varieties are available.

We occasionally see fruit on wild muscadine vines in the late summer, but many wild vines only have male flowers and so don’t produce berries. Cultivated varieties have either “perfect” flowers (ones with female and male parts) or female flowers. In the latter case, the vine needs a self-fertile, perfect-flowered vine or a wild male vine nearby to pollinize it.

Muscadines aren’t the only grapes that we see growing in the wild. Other grapes native to Louisiana include the summer grape (V. aestivalis), graybark or winter sweet grape (V. cinerea), frost or fox grape (V. vulpina), and riverbank or frost grape (V. riparia). (As usual, common names can be confusing, with the same name sometimes applied to different species.) These other grapes are more closely related to each other than they are to muscadines.

Smooth, heart-shaped leaves with teeth of similar sizes along the edges often suggest to us that a grape vine is a muscadine. However, some other species have leaves that look similar. Grapes hanging in bunches rather than loose clusters are a clue that a vine isn’t a muscadine, but vines often lack fruit.

An easy and reliable way to differentiate between muscadines and native bunch grapes is by the vine’s tendrils. The tendril is what wraps around limbs and trellis wires and allows grapes to climb. Most grape species have forked tendrils, but muscadine vines’ tendrils are unbranched.

All grapes (Vitis species) are technically edible, though you might not enjoy eating some of them. Besides the fruit, young grape leaves can be used to make dishes like the dolmas of Mediterranean cuisine.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Troubleshooting Raised Bed Problems: Part 1

Many of us grow vegetables and other plants in raised beds. They’re helpful where drainage is poor. Even where it isn’t, they can make weed management easier and reduce the amount of bending required to grow a garden.

However, raised beds are not always without problems. I’ve had a couple of calls recently from people who had, I suspect, used too much high-nutrient material and ended up with beds that had excessively high salt contents. When we speak of salt in this context, we’re not talking about table salt but about many types of ions, including plant nutrients, that can contribute to salt stress for plants.

The materials used in a raised bed also affect pH. Most vegetables do well between pH 6.0 and 6.5, so gardeners should be cautious about materials that are much more acidic or alkaline.

When building a raised bed, it’s helpful to include some organic materials that have high levels of plant nutrients, but consider the amount that you’re using. Composts vary widely in their contents. Those made from animal manures sometimes have high nutrient and salt contents, while those made from yard waste often have relatively low nutrient levels. (Manure-based composts also bring to mind microbe-related food safety, but I won’t try to address that here.) Mushroom composts tend to have high salt contents and high pHs. These types of materials can be good in moderation, but they usually need to be blended with other, low-nutrient materials.

When people run into problems with their raised beds, they sometimes send the substrate for testing as a routine soil sample. The process used to test soil was developed for field soil (mixtures of sand, silt, and/or clay, with a small amount of organic matter). When these procedures are used on mixtures made up primarily of organic materials, as most raised bed substrates are, the results do not accurately reflect what the plants experience. The nutrient contents shown in these soil reports from raised beds are often much higher than what the plants will be exposed to in the short term.

The LSU Soil Testing and Plant Analysis Laboratory suggests sending substrates that are less than 20% field soil as potting mix samples instead of soil samples. Routine potting mix samples cost $15 each instead of the $11 it costs for a routine soil sample, and the test used requires a greater volume of material.

Potting mix sample reports include results for pH and for concentrations of nitrate, phosphorus, potassium, calcium, magnesium, and soluble salts. The reports provide interpretations of the results, such as “low,” “very high,” and “optimum,” which are helpful when troubleshooting. However, they don’t provide recommendations about how to fertilize, so you may need to contact us for guidance.

In the next article, I’ll write about a couple of other issues people encounter.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Pruning Blueberry Plants in the Summer

In Louisiana, we have a long enough growing season that we can prune blueberry plants shortly after harvest and get regrowth and flower bud development on that new growth. On the other hand, if you wait until wintertime to reduce bush height, you’ll likely be cutting off already-developed flower buds that could have produced fruit.

As a rule of thumb, prune blueberries for height no later than the end of July.

While it’s not absolutely necessary to prune blueberry plants every year, reducing their height can make them easier to pick. The amount of new growth that the plants put on after they’re pruned will depend on their vigor and the fertility of the soil, but as a general guideline, cut them to about one foot lower than the maximum height at which you want to pick berries next year.

An added benefit of pruning blueberry plants shortly after harvest is that flower buds on vigorous shoots put out in the summer tend to break later the following year than flower buds on less vigorous growth produced earlier in the season. This means that in years when we have a late freeze, it’s less likely that flowers on these shoots will be injured by low temperatures.

Besides reducing plant height for ease of picking, the other major step to pruning mature rabbiteye blueberry plants is to remove one to three of the oldest canes each year. This allows more light into the bush so that fruit isn’t just produced on the outside of the canopy. It also encourages plants to grow new canes from the base. We want blueberry plants to produce new canes, since older growth tends to become less fruitful over time.

Removal of several old canes can be done either after harvest or during the winter, when plants are dormant. Look for canes that are roughly one inch or more in diameter at the base and cut them close to the ground. The amount of wood cut out each year should be roughly 10 to 20% of the total wood present.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Some Licenses and Certifications Related to Landscape Horticulture Work

I occasionally get questions from people who are interested in getting into landscape-related work for pay. The easiest type to get into is general yard work, including mowing, edging, and hand-weeding. Without a state license, as long as the work is not on commercial property, one can also engage in “trimming of hedges and shrubbery, under the direction and responsibility of the owner of the property” and pruning trees “under the specific direction and responsibility of the owner of the property” if “the branch to be removed is two inches or less in diameter and is within ten feet of ground level.”

If a person is paid a fee for doing landscape work beyond what is described above, Louisiana generally requires a license. A Landscape Horticulturist license allows a person to do things such as preparing beds, installing landscape plants or sod, giving advice on plant selection and placement, fertilizing, and doing shrub pruning beyond what is described in the above paragraph. Licensing requires passing an exam administered by the Louisiana Department of Agriculture and Forestry (LDAF) and paying a fee. The study guide for the exam is called The Louisiana Manual for the Environmental Horticulture Industry and can be ordered from the Louisiana Nursery and Landscape Association.

It’s not required by law, but some people who do landscaping work also choose to get Certified Nursery and Landscape Professional (CNLP) certification through the Louisiana Nursery and Landscape Association (LNLA). The study guide for this is the same one for the state license exam. LNLA hosts CNLP manual review and exam sessions.

One thing that a Landscape Horticulturist license does not allow people to do is to be paid for a landscape plan itself. While a Landscape Horticulturist can draw plans while preparing to install plants, they cannot sell a landscape design itself. In Louisiana, to do this, one must be licensed as a Landscape Architect. (Describing what’s required to become a landscape architect is beyond the scope of this article.)

Another profession for which state licensure is required is arborists. These are people who, as well as removing trees, care for them by doing things such as pruning, fertilizing, and cabling. As with the Landscape Horticulturist license, to attain the Arborist license, one must pass an exam and pay a fee. The study guide for this exam is the Arborists' Certification Study Guide from the International Society of Arboriculture (ISA). There is a separate certification, Utility Arborist, for those who remove trees or prune “along utility rights of way.”

There are also options to get tree work credentials beyond the required state license. For example, some people choose to become Certified Arborists through ISA.

People who do landscape work sometimes want to be able to, for example, apply herbicides for lawn weeds or use fungicides or insecticides on landscape plants. State law requires those who apply herbicides, insecticides, fungicides, or other pesticides to others’ landscapes for a fee to have a pesticide applicator’s license and commercial applicator certification. (For Arborists, there is an exception that allows application of “…pesticides only for the purposes of retarding decay or disease.”) Those who will be applying pesticides to landscape plants and turfgrass take a general standards exam and the ornamental and turf pest control exam. The study materials for these are the National Pesticide Applicator Certification Core Manual and the Ornamental and Turf Pest Management study guide, respectively. Both can be ordered from LSU AgCenter’s Online Store.

For more information about Landscape Horticulturist, Arborist, and related licenses and permits, you can check out LDAF’s Nursery and Landscape Licensing website (https://www.ldaf.la.gov/plants/nurseries-landscaping). People interested in hiring someone can also use this website to find names of licensed individuals. For information on pesticide licenses, see LDAF’s Pesticide Licensing website (https://www.ldaf.la.gov/plants/pesticides/pesticide-licensing).

There will likely be other requirements for operating a landscape-related business, such as a business license from the local government entity in which it’s based. Organizations such as the Louisiana Small Business Development Center or your local chamber of commerce can likely provide guidance.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Killing Unwanted Woody Plants

People occasionally inquire about how to kill woody vines or unwanted shrubs or trees that keep regrowing in spite of being cut back severely.

An easy option that minimizes risk to nearby plants is to make what’s called a “cut stump” treatment using an herbicide that contains the active ingredient triclopyr.

When this type of application is made, the woody stem is cut near the ground, and the herbicide is applied to the freshly cut surface of the stump. Triclopyr moves down into the roots through the plant’s vascular tissue.

A number of triclopyr-containing products are labeled for cut stump application. BioAdvanced Brush Killer Plus Concentrate, Bonide Stump-Out Stump and Vine Killer, Fertilome Brush Killer Stump Killer, Ortho GroundClear Poison Ivy and Tough Brush Killer1, Pathfinder II, and Stump Stop are examples of products that are applied full-strength, without dilution, when used in this manner. (Look for products that are 8 to 13.6% triclopyr. Some products have similar names but much lower concentrations.)

There are also products with higher concentrations of triclopyr that can be used for stump treatment after being diluted.

The phloem tissue that carries the chemical to the roots is along the inner edge of the bark. So, make sure you get the herbicide along the outer edge of the stump surface and not just in the middle.

Triclopyr-containing products will kill or damage many types of plants, so be sure not to get them on plants you don’t want to kill. Also be aware that, if the treated plant shares a root system with another plant (for example, if one is a sucker of the other, or if roots have grafted together), the herbicide can kill or damage the other plant, too.

Be sure to read and follow label instructions when using any herbicide or other pesticide.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Rooting Out Construction-Related Tree Damage

When I see a tree that appears to be on the decline, one of my first thoughts is usually to consider whether some sort of construction-related activity has gone on in the area. Was a driveway laid over the root system? Did someone dig a trench for a utility line?

There are a variety of ways trees can be damaged during construction. Many of these involve injury to tree roots. This injury can be direct – a site may be graded or excavated so that roots are removed, or a utility trench may be dug, severing the root system.

Injury to roots can also be indirect. Concrete for a foundation or driveway may be laid over part of the root system, or grading may result in additional soil on top of it. Vehicles may be driven or parked over the roots, or construction materials may be stored near a tree, so that soil is compacted. When concrete or too much soil is laid over the roots, or when soil is compacted, tree roots often die due to a lack of oxygen.

Tree damage can also result from changes in the surroundings. Some smaller trees are understory trees and may not do well if large trees around them are cut, exposing them to direct sunlight. Removal of other trees on the site can result in more wind exposure for trees that remain, making them more likely to be blown over in a storm. Trees may be stressed by higher temperatures that result from the presence of concrete patios, for example. Activities at the site might also result in changes to how wet or dry a particular area is.

So what can you do?

Consider what trees are present and which are worth making an effort to keep. If trees close to the planned site of the structure are already showing signs of decline (no leaves at tips of branches, for example) or have sustained significant injury in the past, these should probably be removed. It’s likely to be less expensive to remove trees before a house or other structure is present, and it’s certainly preferable to remove a large tree before it falls on a new structure.

Sketch a map of the site plan, including trees. You may be able to adjust the location of buildings, driveways, utility trenches, etc., to maximize the chances that trees you want to keep will stay healthy. Keep in mind that construction crews must have room to work. Get input from those involved in building so that you’ll know how much room they will need for various activities.

Trees within 30 feet of planned structures are considered at high risk for construction damage. These can be removed, or a special effort can be made to protect them. In addition, other trees that are within approximately 60 feet of the construction site should be protected. Use temporary fences to define the areas that should not be disturbed. It’s recommended that a tree protection fence be no closer to the trunk than 15 times the width of the trunk. In other words, allow at least 1.25 feet from the trunk for every inch of trunk diameter. So, for a tree that is one foot in diameter, the temporary fence should be at least 15 feet from the trunk in all directions. Fences will need to be checked from time to time to make sure that they have not been removed and that construction materials are not being stored within the fenced areas.

If you’re interested in reading more about this topic, take a look at Preserving Trees in Construction Sites (http://extension.msstate.edu/publications/publications/preserving-trees-construction-sites) or Construction and Tree Protection (https://content.ces.ncsu.edu/construction-and-tree-protection).

An arborist can help make calls about the health of existing trees. A list of arborists licensed by the State of Louisiana can be found on this page: https://www.ldaf.la.gov/business/professionals.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Good Insects in the Garden

When extension agents get calls about insects, it is often because one is or appears to be injuring a plant. However, the reality is that roughly 99% of insects are not “pests.” In fact, if you know what to look for, you may see insects that are helping to keep pest insects under control.

Many people have seen aphids on their vegetable or ornamental plants. These are sometimes called “plant lice.” They suck sap out of plants and excrete a sugary substance called honeydew. We often see sooty mold growing on that honeydew. There are a number of beneficial insects and even some fungi that help manage aphids.

We sometimes see aphid “mummies.” The aphids have holes in them and look like they’ve been blown
up like a balloon. This is caused by parasitoid wasps that lay eggs in the aphids. The eggs hatch, and the larvae feed on the insides of the aphids. The larvae pupate and become adults, which make holes in the mummies as they exit.

The larvae of some lady beetles (“lady bugs”) and of green lacewing insects also feed on aphids. Note that the larvae of these insects do not look like the adults, so you might not recognize them. Both look sort of like tiny alligators. Lady beetle larvae are often black and orange, while lacewing larvae are brownish. If lacewing insects are present, you may also see their eggs, which are each perched on a “stalk.”

Like aphids, thrips are common insects, though they are often not noticed because they are so small. Some are problematic because they feed on flowers and thus affect flower appearance or fruit development. Some also spread plant viruses, like tomato spotted wilt virus.

The minute pirate bug is one insect that preys on thrips. Like thrips themselves, minute pirate bugs are not easy to see with the naked eye, but with a hand lens, one can see that they’re black and white. Based on work done in Florida, it was found that having one minute pirate bug for every 40 western flower thrips was enough to provide adequate control.

If you’ve grown tomatoes, you very well may have seen tomato hornworms at one time or another. If you see white cocoons on the back of a hornworm, let that hornworm stay. The cocoons are those of a parasitoid wasp. These wasps lay eggs in the hornworms. After eggs hatch, larvae emerge from the hornworms and spin cocoons on their backs. The wasps will pupate in the cocoons, emerge as adults and, hopefully, go lay eggs in other hornworms.

The final beneficial insect that I’ll mention is the spined assassin bug. The adults of this insect are brown and readily seen with the naked eye. This is one of several different assassin bugs, which often hold other insects with their forelegs while feeding on them.

People sometimes inquire about buying beneficial insects for the garden. While this may be helpful in some cases, it’s a more practical strategy for an enclosed structure like a greenhouse. In the garden, one of the main things to do to encourage beneficial insect activity is to avoid using broad-spectrum insecticides when possible.

The pyrethroid class of insecticides includes ones with active ingredients like pyrethrins, permethrin, bifenthrin, lambda cyhalothrin, zeta cypermethrin, and esfenvalerate. These are some of the most effective options we have for certain insects, like leaffooted bugs and plant-damaging stink bugs. However, they are broad-spectrum and may kill insects that we would rather not kill, too.

Some insecticides have a narrower target range. We have a number of options for caterpillar pests. Insecticides with the active ingredient spinosad or Bacillus thuringiensis subspecies kurstaki are generally effective on caterpillars when they’re small.

Spinosad is also effective on some other insects like thrips and citrus leafminers. Spinosad can still negatively affect bees if they come in contact with the insecticide before it dries, so, as with any pesticide that can harm bees, wait and spray it in the late afternoon or evening when honeybees are no longer active.

Insecticidal soap (often called “potassium salts of fatty acids”) or horticultural oil products can help keep numbers of soft-bodied pests like aphids, thrips, whiteflies, and spider mites low. Good coverage of plant surfaces, including undersides of leaves, is essential when using these, since they work on direct contact with the insect or mite.

These insecticides are generally more effective when pest numbers are few and insects are small, so try to keep a close eye on plants so that you’ll spot problems before they get out of control. Before using any insecticide, be sure to make sure it is labeled for the plant on which you intend to use it, and follow label instructions.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

There’s An Eggplant for Just About Everyone

Once we get past mid-May or so, we’re more limited with regard to planting warm-season vegetables. A lot of them don’t produce as well when temperatures are very hot, but eggplants – like okra, southern peas, and sweet potatoes – are exceptions. These can handle our hot summers.

The first eggplant dish I remember liking was eggplant casserole, a popular dish at a well-known local restaurant in Bogalusa. I assume it was made with the oblong purple eggplants with which most of us are familiar. Later, when I lived in North Carolina and often shopped at the State Farmer’s Market, I learned that I liked thinly sliced white eggplants pan fried in olive oil with Italian seasoning and salt. While in grad school in Baton Rouge, my housemate from Thailand grew another type – a small green eggplant – in our backyard.

Clearly, eggplants come in a range of colors and sizes. Most of those we eat are varieties of the species Solanum melongena. They’re in the nightshade family (Solanaceae) with tomatoes, peppers, and potatoes.

Most eggplants take about 80 to 90 days to produce ripe fruit and can continue producing for six to eight weeks. They’re frost-sensitive, so plant transplants by early July.

Soil pH for eggplants should be in the range of pH 5.5 to 6.8. For every 100 feet of row, 3 pounds (6 cups) 13-13-13, 4 pounds (8 cups) 10-10-10, or 5 pounds (10 cups) of 8-8-8 or 8-24-24 can be mixed into the soil before planting.

Place transplants 2 to 3 feet apart within a row. Begin supporting them with a sturdy stake while they’re still small.

Like tomatoes and peppers, eggplants should be side-dressed when they first set fruit. Calcium nitrate can be used at a rate of 2 pounds (3.5 cups) per 100 feet of row. Once harvest begins, side-dress every three to four weeks to encourage continued fruit production.

Water plants adequately. If you water in a way that gets leaves and fruit wet (e.g., with a sprinkler), do this early in the day so that plants dry quickly and are less likely to develop disease problems.

Harvest eggplants while they’re still shiny. Eggplants with a dull finish are past the point of optimal quality. Cut the fruit’s stem rather than trying to pull or twist it off the plant.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Termite Swarms Remind Us That These Creatures Are Nearby

Formosan subterranean termites swarm between April and July in Louisiana. Some drywood termites also swarm during this time. Swarms are made up of winged male and female termites (“alates”) that are searching for a mate. They lose their wings and go off with a partner to find a nesting site. Many die in this process, but those that succeed become the king and queen of a new colony.

Because Formosan termites swarm in the evenings and are attracted to lights, one way to minimize personal contact with them is to turn off outdoor lights during this time.

Most people who live in Louisiana are aware that steps need to be taken to prevent termite damage to houses and other buildings. Some of these things require a professional, but there are also steps we can take in the landscape to further reduce the chances of termite infestations.

When working in the landscape, avoid disturbing or covering the soil within one foot of the base of the house. A termiticide will typically have been applied in this area at the time of construction or under the terms of a termite contract, and activities in this area can reduce the protection it provides.

Landscape mulches are great in many circumstances, but don’t put them directly next to the base of the house. Termites can feed on mulches with wood or other cellulose-containing materials (cardboard, paper, etc.), and all types of mulch help maintain moist conditions that favor subterranean termites. Likewise, situate landscape plants so that, after they grow to their mature sizes, they’re still far enough from the house to allow you to easily check for signs of termite activity.

Remove fallen limbs and other dead wood from around the house, and take steps to prevent excessively moist conditions near the house.

Termites sometimes infest trees. While most types of termites only feed on dead or injured trees, Formosan termites readily feed on living trees and can increase their risk of falling. Shelter or mud tubes are one sign that a tree is likely to be infested. You can also use a trowel to check for termites in the soil near the base of the tree, next to the root flare. If an infested tree has a large pruning scar where a limb has been removed, “mud” and, during swarming season, winged termites can often be seen there.

If Formosan termites are identified from a tree that is not yet compromised to the extent that it is at an unacceptable risk of falling, a licensed pest control operator can be hired to inject an insecticide-containing foam into the tree.

Formosan termites seem to prefer some tree species to others. Pecan is one that they seem to like. Pecan trees tend to drop limbs and fall in storms, and their attractiveness to termites is another reason not to let them grow close to buildings.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Pruning Plants that Bloom in the Spring

We prune plants for a variety of reasons. Sometimes, we prefer or feel obligated to maintain a certain appearance, such as a raised canopy on a plant that naturally produces growth near the base or a small number of trunks on a potentially multi-trunked plant.

Often, we prune because a plant was put in a place for which it eventually got too large – close to a house, under a window or power line, etc. This type pruning is largely preventable by attention to mature plant size and placement, prior to planting.

One reason to train young trees, particularly, is so that they’ll have good structure and not have the narrow crotch angles and included bark that make branch attachments weak. (If you’ve ever wondered why ‘Bradford’ pear trees tend to break apart in storms, this is why.)

Removing crossing limbs to prevent damage and removing already damaged or diseased parts of plants are other reasons to prune.

When it comes to fruiting plants, we may prune to make picking easier, to increase sunlight penetration and air movement, and to improve fruit quality.

There are several things to consider when deciding if, when, and how to prune. One of the primary considerations regarding when to prune is flowering time and, relatedly, whether a plant flowers on new (current season’s) or old growth.

Ornamental plants that bloom in the late winter and early spring generally bloom on shoots that grew in a previous season. Many of our azaleas, like the southern Indica hybrids (‘Formosa’, ‘George Lindley Tabor’, etc.), are poster children for this. To avoid sacrificing blooms, these should be pruned after flowering.

I’ve been asked how late is too late to prune azaleas. The end of June or first of July is sometimes mentioned as a cut-off date, after which flower buds are likely to be forming for the following year. However, I don’t know exactly when flower bud formation starts here in southern Louisiana. (This stage of bud formation is something that happens within the plant – not something we can see on the outside of a branch.)

Rather than putting off pruning until the end of the window for doing so, if you need to prune your azaleas, you might go ahead and do it fairly soon after blooms fade. This gives plants more time to recover before the weather gets hot.

Other plants that bloom on old growth and should be pruned soon, if needed, include camellias, primrose jasmine, Carolina jessamine, and bridal wreath spirea.

Crape myrtles, chaste trees (vitex), and American beautyberry are examples of the opposite situation. They produce blooms on new shoot growth and so can be pruned in late winter, while dormant, without removing flower buds.

Some groups have species with both types of plants. Among the hydrangeas, mophead or “French” hydrangeas generally bloom on old growth, although there are exceptions (such as the Endless Summer

series). Mophead hydrangeas are unusual among the old-growth bloomers in that they bloom relatively late in the season. Oakleaf hydrangeas bloom on old growth as well, while panicle hydrangeas, like ‘Limelight’, bloom on new growth and can be pruned in late winter.

Many roses bloom on new growth, which is why they’re often pruned in late January or early February. There are some roses, though, that bloom once per year on old growth and should be pruned after flowering. These include the Cherokee rose and Lady Banks rose.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Taking Care of Zoysiagrass Lawns

Zoysiagrass isn’t the most common turfgrass in Louisiana, but it has some advantages, as well as some  downsides. It’s more drought- and wear-tolerant than centipedegrass and St. Augustinegrass while being more shade-tolerant than bermudagrass.

Its tendency to build up thatch and need to be dethatched more often is one downside. Because of its stiffness, zoysiagrass dulls mower blades more quickly than other turfgrasses do and causes them to need to be sharpened more often.

The recommended soil pH range for zoysiagrass is between pH 5.8 and 7.2, similar to those for bermudagrass and St. Augustinegrass.

Zoysiagrass can be fertilized like St. Augustinegrass, at a rate of 1 pound of actual nitrogen per 1000 square feet in both April and June. If additional growth is desired, another application can be made in August. The fertilizer can be either readily soluble or slow release.

Examples of fertilizers and amounts of them that provide 1 pound nitrogen include the following: 3 pounds 33-0-0 or 32-0-10, 6.3 pounds 16-0-8, 6.7 pounds 15-0-15, 7.7 pounds 13-13-13, 10 pounds 10-10-10, and 12.5 pounds 8-8-8. The best choice depends largely on what amounts of nutrients (other than nitrogen) your lawn needs. A soil test report provides this information.

Zoysiagrass is mowed at 1 to 2 inches, like centipedegrass. Use of a reel instead of a rotary mower is often advised but not essential.

When a lawn reaches the point that it feels very spongy when you walk on it, dethatching is likely needed. This can be accomplished with a vertical mower. Core aerators used to address soil compaction can reduce thatch too, thus killing two birds with one stone. Late spring and early summer are generally good times to use either of these pieces of equipment.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Taking Care of Bermudagrass Lawns

In the past, I’ve written articles about how to care for centipedegrass and St. Augustinegrass lawns. These are probably the most common turfgrasses in Louisiana yards. Occasionally, I do get inquiries about other turfgrasses, so I thought I would write about the other two biggies, bermudagrass and zoysiagrass. I’m addressing bermudagrass this week.

Bermudagrass may be more common on sports fields, golf courses, and pastures than in home lawns. It’s highly tolerant of wear (foot traffic, etc.) and more drought-tolerant than centipedegrass or St. Augustinegrass. A significant advantage for people who need to cover large areas is that common bermudagrass and some named varieties can be seeded, making it less expensive to establish than turfgrasses that need to be sodded, plugged, or sprigged.

Probably the biggest downside of bermudagrass, for some situations, is that it’s the least shade-tolerant of the common turfgrasses and needs full sun for optimal growth.

Bermudagrass also requires a good deal of maintenance. As you may be aware, this grass can be a weed where it isn’t wanted, so it may surprise you that more nitrogen fertilizer is recommended for it – especially for hybrid cultivars – than for other warm-season turfgrasses. It also grows quickly and needs to be mowed frequently.

A soil pH between pH 5.8 and 7.2 is recommended for bermudagrass. In some places, lime will be needed to achieve this. You can get a soil test to find out if lime is needed.

Fertilizer can be applied to common bermudagrass at the rate of 1 pound of actual nitrogen (N) per 1000 square feet in April, June, and August. If more growth is desired, another application can be made in July. If you have hybrid bermudagrass, it’s recommended that 1 pound of N be applied in May, too, and an optional 0.5 pound N application can be made in early September.

If slow-release fertilizer is used, some applications can be combined. For example, instead of applying 1 pound N in both April and May to hybrid bermudagrass, you can apply 2 pounds N in April.

Some examples of fertilizers and amounts of them that provide 1 pound N include the following: 3.1 pounds 32-0-10 (32% nitrogen, 0% phosphate, and 10% potash), 6.3 pounds 16-0-8, 6.7 pounds 15-0-15, 7.7 pounds 13-13-13, 10 pounds 10-10-10, 12.5 pounds 8-8-8, and 3 pounds 33-0-0.

The best choice will depend largely on what amounts of nutrients (other than nitrogen) your lawn needs. A soil test report provides this information.

Mowing height recommendations for bermudagrass range from 0.75 to 2 inches. It’s best to mow often enough that you don’t have to remove more than one-third of the total height of the grass when you mow. For example, if you mow at a height of 1 inch, try not to let the grass get taller than 1.5 inches. (I acknowledge that this is a “do as I say, not I as I do” situation.)

Sometimes, soil gets compacted and needs aerification. If you try to stick a knife into the soil when it is neither very wet nor very dry and the blade doesn’t go into the ground easily, the lawn may need to be aerated. Late spring and early summer are generally good times to do this.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Here are Some More Tomato Tips

Tomato plants need to be supported in some way. Stakes, cages, and a string-and-weave system are all options. Support structures for indeterminate (vining) varieties need to be taller (6 feet or more) than those for determinate (bush-type) varieties.

Suckers – shoots that grow between the leaves and the main stem of a tomato plant – are removed from the bases of tomato plants so that fruits will be larger and harvest will begin earlier.

On determinate varieties, only remove suckers under the one immediately below the first flower cluster. In other words, one sucker should be left below the first flower cluster. On indeterminate varieties, remove suckers below the second flower cluster.

Suckers should be removed when they’re about 2 inches long. If you accidentally let one get longer than 4 inches, just leave it. Removing them at that point may do more harm than good.

A problem people commonly experience in tomato gardens is blossom end rot. This is associated with low calcium in the fruit. However, having blossom end rot doesn’t necessarily mean that the calcium level in the soil is low. If soil is limed appropriately to adjust soil pH, soil calcium is typically sufficient.

Blossom end rot can occur because the water supply is irregular. Calcium moves upward with water in the plant, and if soil is allowed to dry excessively, sufficient calcium won’t be able to reach the fruit. On the other hand, if soil is too wet, roots won’t function well, and plants may not take up enough calcium.

Try to keep soil moisture consistent, rather than letting it get too dry or stay too wet. Mulching can help conserve water so that soil doesn’t dry out as quickly and the amount of water available to the plant doesn’t vary as much over time.

Excessive fertilizer can also contribute to blossom end rot, so avoid overfertilizing. Nitrogen in the ammonium form can compete with calcium for uptake by roots, so nitrate-based nitrogen sources like calcium nitrate are recommended for side-dressing tomatoes.

To reduce problems with leaf diseases like early blight and bacterial spot, avoid watering from overhead in the late afternoon or evening. If you water in a way that gets leaves wet – such as with a sprinkler or by spraying water from a hose – do this in the early morning.

Other ways to minimize leaf disease problems include not working in the garden when leaves are wet; rotating where in the garden you plant tomatoes; removing old plants at the end of the season; and doing a good job of managing weeds in the garden.

Fungicides labeled for use on tomatoes and containing chlorothalonil can be used to reduce spread of fungal leaf diseases. Copper-containing fungicides protect plants from leaf diseases caused by bacteria as well as some fungi.

Hornworms can eat a great deal of leaf tissue quickly and sometimes go unnoticed until they’ve done so, since they blend in with the plant. They can be removed by hand if observed. Because they glow under the light of an ultraviolet flashlight (blacklight), this can be used in the evening to help find them.

The tomato fruitworm (same as corn earworm) is often problematic. It may go unnoticed until it has already entered and damaged fruit. Where fruitworms have been a problem, an appropriate insecticide can be applied beginning when plants first start to set fruit. Spinosad-containing insecticides are effective on fruitworms and hornworms.

Insecticides with Bacillus thuringiensis subsp. kurstaki (Btk) or pyrethroid chemicals (active ingredients with names ending in “thrin,” such as permethrin, and esfenvalerate) may work, too, but there is resistance to these in some tomato hornworm populations. Pyrethroid insecticides are effective against stink bugs and leaffooted bugs, as well, but they are also quite hazardous to bees and other beneficial insects.

If you apply an insecticide, wait until late afternoon or early evening, when bees are no longer active. Make sure any pesticide (insecticide, fungicide, or other) you use is labeled for use on tomatoes, and read and follow label directions.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

April is a Good Time to Plant Tomatoes

Few vegetables are as beloved as fresh tomatoes. Growing your own is a chance to get them fresh off the plant and to have your choice of varieties.

In April, there’s little chance of another frost, and it’s still early enough that tomatoes planted now are less likely to experience the excessively warm temperatures that interfere with pollination and fruit set. (If you plant tomatoes after April in Louisiana, it’s advised to use “heat-set” varieties.)

Tomatoes are not the most trouble-free of vegetables. Try not to replant in a place where you planted them last year, to reduce the chance of having trouble with soilborne diseases. Choosing varieties that have resistance to root knot nematodes, Fusarium wilt, tomato spotted wilt virus (TSWV), and/or other diseases will reduce the likelihood of having certain issues. If you water in a way that gets the leaves wet, do this in the early morning rather than the late afternoon or evening.

Good drainage is important for tomatoes, as it is for most vegetables. If drainage at your site is poor, consider growing in a raised bed or container.

Soil pH for tomatoes should be between pH 6 and 7. Lime applied to raise soil pH also provides calcium and, if dolomitic lime is used, magnesium.

In the absence of soil test results, for every 100 feet of row (or 300 square feet), 4 pounds (8 cups) of 8-24-24 or 13-13-13 can be mixed into the soil before planting. Side dress plants at the time of first fruit-set (when blossoms drop and the first tiny fruits appear) with calcium nitrate, at a rate of 1.5 to 2 pounds (2.5 to 3.5 cups) per 100 feet of row / 300 square feet. Side dress again when the third and (optionally) fourth flower clusters set fruit.

Tomatoes can be spaced 18 to 24 inches apart within a row. Wider spacing will allow more air movement and may reduce disease.

If you’re planting in a container, try to find one that’s at least 5 gallons in size, and make sure it has drainage holes in the bottom. Many potting mixes have fertilizer mixed into them, and you can supplement that with a water-soluble fertilizer. Try to find one in which the concentrations of phosphate and potash are greater – or at least as great as – that of nitrogen.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Perennial Vegetables Offer Multiple Years of Harvests

I’m partial to plants that I can plant once and enjoy for multiple years. It’s one reason that I like fruit crops and prefer perennial flowering plants over annual beddings plants.

Most vegetables that we grow are annuals in our climate. Some that are perennials in other places are either heat sensitive (e.g., rhubarb and globe artichokes) or too cold sensitive (e.g., chaya, Malabar spinach, and a number of vegetables commonly grown here as annuals, including tomatoes, peppers, and sweet potatoes) to be reliably perennial here. However, we can grow some perennial vegetables.

Perhaps the thing that most often comes to people’s minds when someone mentions perennial vegetables is asparagus. We eat the plant’s young vegetative shoots, called spears. They’re harvested as they emerge from the ground, when about 6 to 10 inches tall, in late winter and spring.

Asparagus should be planted in a well-drained and well-prepared bed. In much of Louisiana, lime will be needed to raise soil pH above pH 6. Weed management and adequate fertility are important.

Asparagus crowns are planted in winter or spring, and plants should be allowed to grow for at least one year before any spears are harvested. In the second year, a few spears can be cut or snapped off during a 3 to 4 week period in the spring. Once plants are well-established, spears can be harvested for 6 to 8 weeks. Each year, plants must be allowed to produce enough foliage to continue to sustain themselves.

Here’s a fun fact: One of the United States’ best-known asparagus breeders, Howard Ellison, worked at the US Department of Agriculture’s US Field Laboratory for Tung Investigations, which was housed in what is now the Bogalusa Post Office, before becoming a professor at Rutgers University in the 1950s. He was instrumental in developing hybrid all-male asparagus cultivars, such as Jersey Giant and Jersey Knight.

The plant that we in Louisiana call mirlitons or vegetable pears – often called chayote in other parts of the world – is another perennial. The top of the plant is frost-sensitive, but roots can survive with protection from a thick, loose layer of mulch. Like other root-hardy tropical plants, mirlitons should be planted in the spring, after the last frost. We typically eat the fruit, but one can also eat the tuberous roots, young shoots, and other parts of the plant. Choose varieties from Louisiana to increase the likelihood that they will be suited to our climate.

While globe artichokes (those from which we get artichoke hearts, etc.) tend to die in the summer in Louisiana, Jerusalem artichokes or sunchokes are aster family cousins that perennialize here. They’re closely related to sunflowers and likewise have ornamental value, but unlike annual sunflowers, they make an edible tuber (underground stem) that can be eaten as a substitute for white potatoes. This is one of relatively few vegetables that’s native to North America.

Plant sunchoke tubers or pieces of tubers in the spring. Once plants are established, tubers can be dug as needed in the fall and winter. When deciding where to place them, consider that plants can reach 6 to 10 feet tall and spread to the extent that they’re considered weedy. They tend to be less productive in the Deep South than in more northerly locations.

The final plants I’ll mention are cacti. The fruit and pads or cladodes (called “nopales” as a food) of prickly pear cacti (Opuntia spp.) are edible. Elsewhere, fruit is most often cultivated from a species called Barbary fig (O. ficus-indica), and it appears that varieties of this species vary in their cold hardiness. Some may be suited to Louisiana, while others likely are not cold hardy enough. The fruit of the eastern prickly pear (O. humifusa), which is native to Louisiana, is also edible. Great care must be taken when handling and preparing either the fruit or pads of prickly pear cacti, since both have hair-like spines called glochids, in addition to the more obvious spines found on the pads.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Fertilizing Landscape Beds

Sometimes landscape beds are installed and, perhaps, mulch is refreshed and pruning is performed from time to time, but little attention is given to replacing nutrients that have leached out of the soil with rain or irrigation water or that have been removed in pruning waste. Over time, plants become less vigorous.

Late winter and early spring, as the aboveground parts of plants start growing again, are good times to fertilize many plants. This includes shrubs, small trees, and herbaceous perennials in landscape beds.

Taking a soil test and getting the results is preferable for knowing what amounts of different nutrients are needed and if soil pH needs to be adjusted. However, if there is no reason to believe that soil nutrient levels might be excessive, an application of a “complete” fertilizer – one containing nitrogen, phosphorus, and potassium – can be made at a moderate rate without one.

Fertilizing at a rate of 1 pound of actual nitrogen per 1000 square feet, or 0.1 pound per 100 square feet, is a rule of thumb when maintaining landscape ornamentals. If you’re using a slow-release fertilizer, you might consider increasing the nitrogen rate to 0.2 pound per 100 square feet. (Slow-release fertilizers are coated in such a way that nutrients are released over time and, for landscape beds, are preferred to ones like 13-13-13 or 8-8-8 that are readily soluble.)

For example, you could use 0.7 to 1.4 pounds of a slow-release 15-9-12 (15% nitrogen) product, 0.8 to 1.6 pounds of a slow-release 12-6-6 product (12% nitrogen), 0.8 pound 13-13-13 (13% nitrogen), or 1.3 pound 8-8-8 (8% nitrogen), per 100 square feet of bed area. These are just a few of many possible fertilizers that could be used.

Mixed fertilizers generally have a density of about 1 pound per pint, or per 2 cups, so 0.5 pound of fertilizer would be about 1 cup of fertilizer.

While landscape beds can be fertilized in late winter or early spring, wait until April to apply any nitrogen-containing fertilizer to warm-season turfgrasses. Fertilizing turfgrass too early can promote winter weed growth and predispose grass to the fungal disease large patch.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

I’m throwing in a request here: In Extension, we’re asked to get feedback on the impact of what we do. This is relatively easy for things like in-person meetings, where we can hand out a questionnaire. It’s harder for news articles, but I’m giving it a try. If you have feedback on ways that my articles have helped you, or on ways that they could be more useful, please consider sending me an email. Thank you.

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).

LSU AgCenter's Weekly Message

Snap Beans Can Be Planted in March

Snap bean can be planted relatively early in the year, compared to many warm-season vegetables. The plants are frost sensitive, but since they’re planted as seeds and it takes 7 to 14 days for them to emerge, planting in early to mid-March in the southern part of Louisiana will often allow them to escape our last frost. The soil temperature should be at least 60 degrees F.

Seeds can be planted till mid-May in the spring and can then be sown again between mid-August and mid-September for a fall harvest. Because snap bean flowers are sensitive to high temperatures, planting between mid-May and mid-August is not advised.

There are both bush and pole varieties of snap beans. Pole beans need a structure to climb and typically take longer to start bearing than bush varieties do, but once they do, they produce for a longer period. To extend the harvest of bush beans, a new planting can be made every couple of weeks.

Pole bean varieties include Kentucky Blue, McCaslan, and Rattlesnake. Bush varieties include Bronco, Bush Blue Lake 274, Provider, Roma II, Royal Burgundy, and Strike.

Soil pH for snap beans should be between pH 5.5 and 6.8.

For every 100 feet of row or 300 square feet, 2.5 pounds (5 cups) of 8-24-24 or another complete fertilizer can be mixed into the soil before planting. Snap bean seed can be damaged by direct contact with fertilizer, so mix fertilizer into the soil well. Optionally, you can also side-dress plants three to four weeks after planting with calcium nitrate, at a rate of 1.5 pounds per 100 feet of row / 300 square feet.

Within each row, space bush bean seeds 2 to 3 inches apart. When planting pole beans, hills with 4 to 5 seeds can be spaced 6 to 12 inches apart. Plant seeds about 1 inch deep.

It will take approximately 50 to 55 days till the first bush beans are ready to pick and about 60 to 65 days for pole beans. Harvest beans before pods starts to bulge due to the growing seeds and while they’re still tender.

Lima or butter beans can be planted soon, too. Because they don’t tolerate cool soil as well as snap beans, wait till later in March, when the soil temperature is at least 65 degrees F.

Let me know if you have questions.

Click here for previous LSU AgCenter's Weekly Messages

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).