Lafayette Parish Master Gardeners

GERALD'S CORNER

By Gerald Roberts
Horticulturist/Master Gardener Program Coordinator
LSU AgCenter

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December 2013

12/1/2013

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Hello Master Gardeners,
Along with the eager anticipation of the upcoming holidays, comes many calls to the LSU AgCenter's Extension office regarding citrus production in home gardens.

The strong interest in citrus production stems from the fact that it's been several years since we have had hard, extended freezes that are capable of severely damaging or killing citrus trees. This has accounted for the increasing number of trees that are producing fruit. Even though the biggest threat to citrus trees in Louisiana is freezing temperatures, here in South Louisiana we enjoy the ability to produce a variety of citrus fruit compared to our neighbors in the northern part of the state.

The first question that should be asked before deciding what type of citrus to plant is which types are the most cold hardy. Generally speaking, lemons and limes are the least cold hardy. Most of us can remember kumquat trees being around as we grew up; they are the most cold hardy, followed by satsumas, sweet oranges, grapefruit, and finally lemons and limes. As I mentioned earlier, even though it has been several years since we have experienced temperatures low enough to damage trees, we know that sooner or later it's going to happen. Part of the decision when planting citrus is that once planted, eventually freezing temperatures will damage or kill trees. Two varieties of kumquats are planted, one being Nagami (oblong, tart) and the other, Meiwa (round, sweet). If planting satsumas, choose from Brown's Select (which ripens mid-October), Owari (which ripens mid-November) or Armstrong Early (which ripens from late-September through October). For sweet oranges, choose between Washington Navel, Louisiana Sweet, or Hamlin Sweet. More Blood Oranges (so named because of red pigment in the flesh) should also be considered. For grapefruit, choose the popular Ruby Red (the which matures in December) and Rio Red (which matures in early November). Grapefruit can be kept on the tree until May and still maintain good quality. Since freezing temperatures in November and December has the potential to be more damaging than freezes in February, many people prefer to wait to make new plantings until mid to late January or February. Early freezes can cause more damage to trees that have not been sufficiently harden by exposure to cold temperatures than trees that have been hardened by a month or so of cold temperatures. Some factors that determine the extent of damage to citrus trees exposed to freezing temperatures are as follows:
  • the actual temperature reached
  • the duration of time of the freeze
  • the timing of the freeze
  • the age and health of the trees

Older trees in good health will suffer less damage than younger trees or trees that are stressed by diseased.

Let me add that there is a difference between fruit damage and damage to leaf and wood tissue. Trees that are loaded with fruit, regardless of type of citrus, can easily be damaged by several hours of 26-to-28-degree temperatures. If you have trees that have mature fruit and the temperature is predicted to fall to 28 degrees or below for several hours, it may be good idea to harvest as much fruit as possible.

As far protecting the trees themselves, the LSU AgCenter's research shows that trees that are grown with bare ground underneath them generally have a greater degree of survivability that those grown with grass. It is believed that on sunny days, bare ground absorbs heat during the day and releases it after dark, possibly lessening the damage. The other recommendation is to cover the entire plant allowing the cover to extend all the way to the ground. Adding Christmas lights beneath the cover can provide added protection. Be sure to remove the cover the next morning. Remember that despite the threat from freezing temperatures on citrus, it is a fruit species that is considered to be fairly easy to grow and also provides tasty and nutritious fruit.
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November 2013

11/1/2013

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Hello Master Gardeners,

As the year winds down and cooler temperatures begin, please keep in mind that here, in south Louisiana, fall is transplanting time – especially for trees and shrubs. I am focusing on trees for this month for two reasons. The first being that I, like so many of you, appreciate and value the contributions that trees make throughout our community. The second reason is I’m increasingly getting calls from homeowners asking about the health of trees, how to properly maintain trees, tree removal, etc. During site visits I encounter variety of problems that could have been avoided or diminished with some planning and a little research. The first thing that is recommended when deciding to plant a tree or trees is what is the intended use or purpose. Is its primary purpose shade or energy conservation? Is it going to be used primarily for beautification? Is it going to be used for wildlife habitat since many birds and animals depend on trees for food and shelter? If you consider what the intended uses are for a tree or for trees, then that directly impacts what you’ll plant, where you’ll plant it, and the required maintenance. Trees that have been properly selected, positioned, and cared for are a reflection of homeowners who have an appreciation for their environment. Trees are a long-term investment and we must not only think about how trees will benefit us but how they will benefit others and who will be responsible for the maintenance and upkeep long after we’re gone. For whatever reason that you want to invest in a tree or trees, one of the most neglected considerations is the size of the tree at maturity. A mature tree is a tree that has reached a desired size or age for its intended use. Remember that size, age or economic maturity varies , depending on the species and intended use. For example, most people who planted or plan to plant live oak trees are not aware of the space requirements as the tree grows and matures. A live oak tree can dominant an area if not given adequate space to grow. It’s not only the spread of branches but also the root spread that needs to be considered at planting. I personally planted 3 live oak trees in 1980, and have already had to remove two, and with the third one I’ve been forced to remove several large branches that were beginning to hang over my house. Unfortunately I see this scenario replayed over and over again throughout Lafayette and across many communities in our State. I singled out live oaks because of the familiarity of these trees by most people since live oaks are abundant and beautiful and add so much beauty to our outdoor living areas and property in general.

Anyone wanting to plant trees can find endless resources on the subject. The LSU AgCenter website – www.lsuagcenter.com has an abundance of information available to help make important decisions about tree planting. On the LSU AgCenter’s website there is a publication called “Guide to Successful Trees – Publication #2631.” It provides all the information you’ll need to make those important decisions from selecting the proper trees for your intended purpose to proper transplanting, to care and maintenance during and after establishment. There is even a section on common tree problems and choosing an arborist. Another publication is called “Trees for Louisiana Landscapes – Publication #1622.” This is a smaller publication but still contains a wealth of valuable information on selecting, transplanting, and the care and maintenance of trees.

Since fall is transplanting time, I’d like to mention how important it is that once the species of a tree or trees is selected for planting, that the proper transplanting techniques are followed. Root establishment is critical during that first year of transplanting, especially getting that tree or trees through the first summer. It must be noted that it can easily take at least a year and several additional months before trees are considered established. This is an important point because there are some people that honestly believe that after a few month trees are on their way and need no further care. Here are a couple of important points I’d like to make when transplanting trees: first, dig the transplanting hole at least twice the width or diameter of the root ball of the tree; next, don’t dig the transplanting hole any deeper than that which will allow the tree to sit in the hole at the same depth it was growing in the container, or at the same depth it was growing before being dug in the case of field grown trees.

One of the biggest mistakes where trees are planted is that they’re transplanted “TOO” deep. Because of our soil type, less than ideal drainage, compounded by improper mulching, we see issue of root rots which leads to the death of many trees. Additionally it is no longer acceptable to amend the soil that is used as a back fill once the tree is in the transplanting hole. Backfill the hole with the same soil that was removed from the hole. This is the soil that the tree will have to adjust to and live in for the rest of its life. Amending the backfill soil – especially with an amendment that is high in organic matter – may create a waterlogged condition around the root system especially during periods of prolonged rainfall, which again increases the possibility of root rots.

Another common practice that I take issue with is improper mulching. We all are aware of the benefits of mulching such as it reduces weed growth, reduces soil compaction, conserves moisture, add nutrients and improves the soil structure, etc. However, volcanic or pyramid mulching – which is placing mulch high and tight around the lower trunk of trees – is improper and leads to rot issues. Avoid placing mulch over the root collar. The root collar is the transition zone between the stem/trunk and the roots at the soil line of a tree. That area should never be covered up by mulch because it can leads to the buildup of moisture which can lead to rot issues. There’s been times where I’ve pointed this practice out and been told it’s “never been a problem with my trees.” To that I say why take the risk if you value trees; talk to someone who’s had to pay someone to take a tree down because of decline due to rot. The depth of mulches can also lead to problems. I have seen mulches pile high and tight against the lower trunk of trees sometimes to a depth of as much as a foot or more. Mulching trees to a depth of more than 3 -4 inches can lead to problems. There are some species of trees that tolerate pyramiding or volcanic mulching more than others, but under no circumstances should it ever be done. Mulching to a depth of 3 to 4 inches away from the root collar to the drip line will go a long way towards contributing to the long term health and performance of trees. Both issues, transplanting too deeply and volcanic or pyramid mulching is common, not just with home owners but also with landscape maintenance professionals who are getting paid to sometimes engage in practices that are not beneficial to trees.

Let Me Conclude By Stating That The Dormant Season Is Also The Major Pruning Period For Trees. Improper Pruning Practices Contribute To More Problems With Trees Than Is Necessary. By Neglecting To Properly Train Trees When They Are Young Leads To Structural Defects That Have To Be Addressed When Trees Are Much Older And Much Bigger. This Leads To More Shock To The Tree, Larger Wounds Because Of The Removal Of Larger Branches, Which Also Present Increased Safety Hazards. Anyone That Has Trees That Are Structurally Defective Because Of The Lack Of Pruning And Training While The Trees Were Smaller, Needs To Consult A Licensed Arborist. Please Consult The Lsu Agcenter’S Website For Recommendations On Selecting An Arborist. Information On Recommended Pruning Practices Can Also Be Found On The Lsu Agcenter Website. Additionally, Someone Who Is Credited With Studying Pruning Techniques And How Trees Respond To Wounds, Advises That Pruning Paint Or Sprays Serve No Useful Purpose And In Some Cases May Slow Down A Tree’S Natural Ability To Cover Or Seal Wounds. That Person Is Dr. Alex Shigo, Plant Pathologist With The United States Department Of Agriculture’S Forest Service. I Highly Recommend Reading Some Of Dr. Shigo’S Studies And Recommendations On Pruning And Training Trees.

Selecting the right tree for the right location is very important. So is proper transplanting, proper mulching and
pruning. Selecting and transplanting is only the beginning. The care and maintenance can determine whether or not
trees gives us satisfaction by meeting our expectation for their intended uses.
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October 2013

10/1/2013

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PictureApricot Drift rose. (Photo by Allen Owings)
HAMMOND, La. – One of the great new groups of almost-everblooming plants, the Drift series of low-maintenance roses, fits a special niche in the shrub rose market. These roses are from Conard-Pyle/Star Roses, the same folks who gave us the Knock Out series of low-maintenance landscape roses. All colors in the Drift series of roses have been designated Louisiana Super Plant selections for fall 2013.

Drift roses are a cross between full-size ground-cover roses and miniature roses. From the former they kept toughness, disease resistance and winter hardiness. From the miniatures, they inherited their well-managed size and repeat-blooming nature. The low, spreading habit of Drift roses makes them perfect for small gardens and combination planters.

Colors in the Drift roses include pink, coral, red, peach, apricot (double blooms), sweet (clearer pink double blooms) and the new popcorn (whitish yellow). All of these seven varieties bloom from spring to early frost. Ranging from scarlet red to bright soft peach, they provide the gardener with a complete range of color solutions for landscape use or in containers.

We find that Drift roses have about five flower cycles a year. The spring bloom in April and the fall bloom in October, as with most other roses, are the peak times for best performance. The late-spring-to-early-summer second bloom is also impressive.

Fall is a great time to plant Drift roses. Be sure to put them in a well-prepared bed, and space individual plants a minimum of 3 feet apart. It would be best to plant them 4-5 feet apart if you are thinking long term. The soil pH for roses needs to be between 6.0-6.5.

PicturePeach Drift rose flowers. (Photo by Allen Owings)
As with other roses, Drift roses need full sun – eight hours a day is best. These ground-hugging, ever-blooming shrubs are perfect as a border or bedding plant. They grow 2-3 feet wide and 2-3 feet tall and make a stunning low hedge or border edge.

In future years after planting in the fall, fertilize Drift roses in the spring with a good dose of slow-release or timed fertilizer – which releases nutrients to the plant when it needs it most – and you're set for the season. Another fertilizer application in late summer would help plants bloom better into fall, especially in new landscape beds where nutrients may be lacking.

Mulch is important for roses. It helps buffer the cycle from wet to dry, keeps the feeder roots from drying out and helps to establish the roots quicker. And you water less.

These low-maintenance roses are highly disease resistant. They require no spraying. Blackspot disease has been very minimal on plants grown in Louisiana. Bed preparation, irrigation and proper fertilization management are the keys to success.

Louisiana Super Plants for landscapes are designated every spring and fall by the LSU AgCenter in cooperation with the Louisiana Department of Agriculture and Forestry. Two additional Louisiana Super Plants will be named later this fall – a bedding plant in October and a tree in November.

Try these new Louisiana Super Plants – especially the new Drift roses – in your landscape. They combine wonderfully with flowering perennials, ornamental grasses and more.

Dr Allen Owings
LSU AgCenter Hammond Research Center

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August 2013

8/1/2013

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After consulting Dan Gill and reviewing the issues and problems that I’ve dealt with the past couple of months I’ve decide to just discuss “ Garden Tips” for August!

Transplant fall tomatoes plants in your garden by mid-August. One of the issues that vegetable gardeners fail to realize is that insect and disease pressure is generally greater in the fall than the spring. This means that you need to be watchful and address pest problems when they begin-when itfs easier to bring under control. Be sure to thoroughly read the label before apply any pesticide. The label contains important information to help you address the problem, to keep you and others safe, also to keep the environment safe.

Water your vegetables and flower gardens deeply and thoroughly once or twice per week during dry weather. When a good soaking rain occurs, adjust your watering schedule accordingly. A daily watering is not recommended for established plants as it will increase the risk of disease and it encourages a shallow root system. Newly seeded beds, however, should be watered daily until the seeds come up. New transplants also need to be watered more frequently. Remember that plants in containers may need to be watered daily.

Remove the old brown canes that produced this year’s fruit from blackberry bushes if you’ve haven’t already done so. These brown canes will not produce again. The green vegetative canes should remain, but can be tipped to control their height and promote lateral growth. These are the canes that will produce next year’s crop.

Chinch bugs become very active in lawns at this time of the year. Look for symptoms such as dead areas, or straw or tan colored areas especially in sunny dry locations such as along concrete surfaces, next to driveways, sidewalks, or along the street. If you notice these areas getting bigger by the day it may be chinch bugs. Treat with Talstar, Bifenthrin, Acephate or any other labeled products.

If you've noticed that your rose blooms are not quite as vibrant as they were earlier in the year, blame it on the heat. Rose blossoms are often smaller, and the color not as brilliant, during the stressful midsummer months. As the temperatures moderate the quantity and quality of the blooms will improve. Prune ever--]blooming roses back about one--]third their height in late August or early September. Also, remove any dead canes and weak spindly growth. This pruning prepares the roses for the outstanding blooming season in October and November. However, if you have once--]blooming roses that bloom only in spring or early summer and stop, or youfll be reducing flowering next year.

As we progress into later summer and fall you may notice a fine silvery webbing on the bark of area trees. This is being caused by tiny insects called psocids or bark lice. These are tiny scavengers that consume organic matter and other debris in the cracks and crevices on the bark of trees. They are harmless and no control is needed.

Harvest pears by late August. The best fresh eating quality is produced when the fruit is ripened off of the tree. Pick firm pears that have begun to show slight yellow or red blush. Wrap individual pears in newspaper and place in paper bags or cardboard boxes. The pears will soften in about 7--]10 days. This process is not necessary if you intend to cook and then freeze, or can the pears.

If needed, dig and divide Louisiana irises, Easter lilies, and calla lilies this month.

Control caterpillar problems on ornamentals with a pesticide containing BT, Spinosad or Sevin ( carbaryl ). BT is a bacterium that only attacks caterpillars and is harmless to other organisms. It is essentially nontoxic and is appropriate for use by organic gardeners. Spinosad is also organic. Make applications before damage is too extensive, and make sure the damage is fresh and that caterpillars are still active before you treat. Keep these insecticides well away from butterfly garden areas because they are also toxic to butterfly caterpillars.

Continue to deadhead annual bedding plants by removing old faded flower blooms before they go to seed. This will encourage the production of more buds for extended flowering. Some gardeners will actually deadhead individual flower heads on crape myrtles as they fade, thus promoting more vegetative growth and more blooming. However, if you’ve got crape myrtles that are tall then it’s not practical.

Delay any type of weed control on your home lawn that would require the application of an herbicide. Be very cautious of applications at this time of the year. We often see turf injury from herbicide applications, especially when daytime temperatures climb into the 90’s.

Fig trees can be sprayed as soon as production ends to prevent a fungal disease called Fig Leaf Rust. Use Bordeaux mixture according to label directions and make sure to thoroughly cover the underside of leaves. Symptoms of fig leaf rust appear as brown spots covering the leaves, which can cause the leaves to die and fall off the tree.

The last application of fertilizer to your lawn should be made this month. Fertilizing lawns with a high nitrogen fertilizer past August could interfere with grass hardening to deal with cold temperatures. It may also promote brown patch disease especially in St Augustine grass.

Hope you’ll find these garden tips helpful and happy gardening!!!


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June - July 2013 

6/6/2013

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Over the past several months, I’ve been getting requests to go and survey shade trees that are either in decline or dead. Whenever we plant trees it is a long-term investment that we want to be successful. That is why we always recommend doing whatever research that is necessary in the selection of a tree or trees to plant. We must always select trees that have proven to perform under our grow-ing conditions, including soil type, drainage, climatic conditions such as heat, cold, drought, and rainfall. Additionally, we also have a responsibility in the care and maintenance of planted trees or trees that already exists. During the past couple of Master Gardener classes, we discussed both proper and improper pruning practices, and we also looked at various pruning practices on the grounds of Ira Nelson Horticulture Center. Everyone that participated in that particular class indicated how beneficial it was to them.

Another major practice that we know greatly benefits trees is mulching. Trees and many other plants benefit tremendously from mulching because mulching reduces soil compaction, suppresses weeds, conserves moisture, and regulates soil temperatures. Also, as mulch decomposes it softens the surface of the soil underneath it, which in turn, increases the percolation of water to feeder roots. Mulching adds beneficial nutrients and improves the soil structure.

There are a couple of common practices that I encounter too often during many of my home or site visits to survey problems with trees. The first is when I come across nice established trees that are being heavily damaged by both homeowners and professional landscape maintenance professionals, or city or parish employees with string trimmers/weed eaters and lawn mowers. The major damage occurs a couple of inches above the soil line to the major trunks. This resulting damage is stripping or gouging bark which leads to severe stunting or death. It makes me wonder if this problem comes from not be aware or being in a hurry and not being careful. Either way, the damage is unnecessary and harmful to trees, especially when compounded by the normal stresses placed on trees by pests, drought, excessive rainfall, poor drainage, and wind damage!!

The other practice is improper mulching!! For the life of me I don’t understand why anyone would take the extra time to pile mulch 8, 10, or 12 inches high and tight around the trunk of any tree or plant. This leads to all kind of problems and diminishes all of the benefits of mulching that I discussed earlier in this article. Dan Gill and Allen Owings refer to this as “volcanic mulching” since when viewed from the side, the mulch comes to a peak high against the trunk of a tree. Plain and simple, this can lead to serious issues of rotting. Anytime mulch is place over the root flare of trees (the point where the main trunk and the roots meet), it increases the potential for rot. Certain species of trees are susceptible. Trees that don’t tolerate less than ideal drainage or are located in poorly drained areas are much more likely to have rot issues, again leading to stunting , poor performance and possibly death. I communicated with Dr. Owings this morning, and he reiter-ated that no mulch should be piled high and tight against the trunk of any tree. Mulch should be spread out ideally to the drip line or canopy edge to an average maximum depth of 4 inches, and then, top off every 6 -12 months or so to replenish after it decomposes and settles.

Based on my personal experiences during visits all over Lafayette and surrounding Parishes, mulching properly and avoiding dam-ages to trees with lawn mowers and string trimmers would go a long way towards maintaining tree health at a level where we can enjoy the great benefit provided to us and wildlife by trees. I truly believe that as educators, it is our responsibility to informed the uninformed, make aware the unaware, by politely pointing out incidences of improper mulching and physical damages whenever we witness either.

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    Gerald Roberts

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

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