by Daniel J. Leonard | Jul 26, 2016
The Live Oak (Quercus virginiana) is one of the most iconic figures of the Deep South. Mentioning the words Live Oak invokes all sorts of romantic nostalgia of yesteryear and the reputation is not unearned. In fact, many Live Oaks still stand that were growing on American soil when the first English settlers set foot on Plymouth Rock. They are long-lived, picturesque trees that also happen to be nearly bulletproof in the landscape. Given these factors, it is not surprising that Live Oak is far and away the most common tree included in both residential and commercial landscapes in the Coastal South. However, even the venerable Live Oak is not without its problems; this article will discuss a few of the more common issues seen with this grand species.
The Angel Oak near Charleston, SC
Few conditions afflict live oak but when they do, improper planting or cultural practices are usually at play. Observing the following best management practices will go a long way toward ensuring the long-term health of a planted Live Oak:
- Remember to always plant trees a little higher than the surrounding soil to prevent water standing around the trunk or soil piling up around it, both of these issues frequently cause rot to occur at the base of the tree.
- If planting a containerized tree, remember to score the rootball to prevent circling roots that will eventually girdle the tree. If planting a B&B (Balled and Burlap) specimen, remember to remove the strapping material from the top of the wire basket, failure to do this can also result in the tree being girdled.
Live Oak has few insect pests but there are some that prove bothersome to homeowners. The following are two of the most common pests of Live Oaks and how to manage them:
Typical galling on Live Oak
Galls are cancerous looking growths that appear on the leaves and twigs of Live Oak from time to time and are caused by gall wasps that visit the tree and lay their eggs inside the leaf or stem of the plant. The larvae hatch and emerge from the galls the following spring to continue the cycle. These galls are rarely more than aesthetically displeasing, however it is good practice to remove and destroy gall infected stems/leaves from younger trees as gall formation may cause some branch dieback or defoliation. Chemical control is rarely needed or practical (due to the very specific time the wasps are outside the tree and active) in a home landscape situation.
- Black Twig Borers can also be problematic. These little insects seldom kill a tree but their damage (reduction of growth and aesthetic harm) can be substantial. Infestations begin in the spring in Northwest Florida, with the female twig borer drilling a pen-head sized hole in a large twig or small branch and then laying her eggs in the ensuing cavity. She then transmits an ambrosia fungus that grows in the egg-cavity, providing food for the borer, other borer adults, and her offspring that take up residence and over-winter in the twig. The activity of the insects in the twig has an effect similar to girdling; the infected twig will rapidly brown and die, making removal and destruction of the infected branches a key component
In conclusion, though there are a few problems that can potentially arise with Live Oak, its premier status and continued widespread use in the landscape is warranted and encouraged. It should be remembered that, relative to most other candidates for shade trees in the landscape, Live Oak is extremely durable, long-lived, and one of most pest and disease free trees available. Happy growing!
by Beth Bolles | Jul 7, 2016
Many of the plants in our gardens have been developed and discovered that offer interesting characteristics. These may include leaves with variegations, dwarf growth habits, or even contorted stems. We enjoy these plant differences and many of these plants are big business in the nursery trade. In nature, it is likely these interesting plant mutations would not survive as they are less likely to be able to reproduce successfully. Horticulture professionals keep these plants available most often by propagation through cuttings and tissue culture.
Sometimes in the landscape, nature prevails and we see one of our favorite plant varieties revert back to its original or “wild” form. You may see a stem on a variegated plant that has larger leaves that are all green.
‘Butterfly’ Japanese maple has beautiful variegated foliage. One stem has reverted to an original form with large green leaves. Prune out this stem. Photo by Beth Bolles
These stems often grow more vigorously and can use nutrients and energy that the remainder of the plant needs. As soon as you see these different stems, prune them back to a connection with another stem that exhibits the plant characteristics you want.
by Mary Salinas | Jul 7, 2016
The Zika virus has made us all more aware of the need to avoid getting bit by mosquitoes when we travel to those destinations that have confirmed reports of Zika infected mosquitoes. The Centers for Disease Control and Prevention lists the countries and territories that have travel notices to consult prior to planning a trip or traveling.
The invasive mosquitoes Aedes aegypti (left) and Aedes albopictus (right) occur in the Americas, including Florida, and have been implicated in the transmission of Zika virus.
Credit: J Newman, UF/IFAS/FMEL
The Florida Department of Health has recommendations for preventative action to take when traveling to any location that has confirmed Zika virus.
- You should use an insect repellant (following all label instructions) with any of these active ingredients:
- DEET
- Picaridin
- Oil of lemon eucalyptus
- Para-menthane diol
- IR3535
- Wear long-sleeved shirts and pants
- Wear clothing that is pre-treated with permethrin or apply a permethrin product to your clothes, but not your skin!
- Avoid getting bitten while you sleep by choosing a place with air conditioning or screens on windows and doors or sleep under a mosquito bed net.
According to the Georgia Department of Public Health you should also protect yourself against mosquito bites for at least a week after you return home from any location that has confirmed Zika. You may have an active infection without symptoms that can be spread to others through mosquito bites.
Now let’s talk about mosquito control in your own landscape.
Even though we don’t have confirmed Zika infection in Florida mosquitoes at this writing, mosquitoes in our state can transmit other diseases such as: eastern equine encephalitis, dengue fever, dog or cat heartworm, chikungunya, malaria, St. Louis encephalitis and west Nile virus.
Let’s first explore what kind of environment in your landscape and around your home is friendly to the proliferation of mosquitoes. Adult mosquitoes lay their eggs on or very near water that is still or stagnant. That is because the larvae live in the water but have to come to the surface regularly to breeze. The small delicate larvae need the water surface to be still in order to surface and breathe. Water that is continually moving or flowing inhibits mosquito populations.
Look around your home and landscape for these possible sites of still water that can be excellent mosquito breeding grounds:
- bird baths
- potted plant saucers
- pet dishes
- old tires
- ponds
- roof gutters
- tarps over boats or recreational vehicles
- rain barrels (screen mesh over the opening will prevent females from laying their eggs)
- bromeliads (they hold water in their central cup or leaf axils)
- any other structure that will hold even a small amount of water (I even had them on a heating mat in a greenhouse that had very shallow puddles of water!)
You may want to rid yourself of some of these sources of standing water or empty them every three to four days. What if you have bromeliads, a pond or some other standing water and you want to keep them and yet control mosquitoes? There is an environmentally responsible solution. Some bacteria, Bacillus thuringiensis ssp. israelensis or Bacillus sphaericus, only infects mosquitoes and other close relatives like gnats and blackflies and is harmless to all other organisms. Look for products on the market that contain this bacteria.
For more information:
Zika, a Mosquito-Transmitted Virus
Mosquito Repellents
UF/IFAS Mosquito Information Website
Florida Container Mosquitoes
by Mary Salinas | Jul 7, 2016
Peppers and tomatoes are in the same plant family – solanaceae or more commonly known as the nightshade family – and can be susceptible to some of the same diseases. This is true of Tomato Spotted Wilt Virus (TSWV). The solanaceae family includes potatoes, eggplant, tobacco, petunia, tomatillo and deadly nightshade in addition to pepper and tomato.
Pepper with TSWV. Photo credit: Mary Derrick, UF IFAS Extension.
This virus is spread by very small insects known as thrips. They acquire the virus as larvae when feeding on an infected plant and then transmit the disease when they fly to other susceptible plants as adults.
Initial symptoms are yellowing and distortion of the leaves. The leaves can also display yellow or brown circular ring spots. The severity of the virus can depend on the particular cultivar of pepper, its age and the environmental conditions in which the pepper is growing. Fruit can develop yellow, brown or ring spots as well.
TSWV infection showing ring spot on leaves and lesions on fruit. Photo credit: Mary Derrick, UF IFAS Extension.
If you think your pepper has TSWV, consult your local extension agent to confirm the diagnosis. But once infected, there is no treatment for the plants and they should be pulled up and disposed of in the trash to prevent other susceptible plants from becoming infected.
For more information:
Some Common Diseases of Pepper in Florida
by Mark Tancig | Jul 5, 2016
When you don’t know what’s ailing your plant, ask an expert.
Many gardeners get stumped when a favorite plant of theirs comes down with a strange “something”. Many of these gardeners know about UF/IFAS Extension and call their local horticulture and agriculture agents for assistance in figuring out what’s going on. However, even these experts are often stumped by what they see. Fortunately, the agents have another layer of experts to fall back on. In addition to the resources in Gainesville, we have the Plant Disease Diagnostic Clinic, located at the North Florida Research Center in Quincy. Plant pathologists here can help determine what fungus, bacteria, virus, or viroid may be the problem.
Plant pathologists are basically plant doctors. They use all sorts of sophisticated techniques to determine what is the cause of a particular plant problem, from growing out fungal spores to examining DNA. Not only do these plant doctors tell us what the ailment is, they also provide recommended cures, or control options. They are also doing research to prevent different diseases from taking hold in our area and reduce the impact on our local growers.
Plant pathologist at work!
At a recent workshop in Quincy, we learned that plant pathology researchers are working on a fungus that affects watermelons, virus and bacteria that can wipe out a farmer’s tomato crop, and a virus that could impact our local roses. Working as a team of scientists, they study these pathogens in the lab and conduct controlled field experiments to figure out which techniques are most effective. Some of this research is leading to different methods and/or products that can help growers and gardeners alike keep their fields and landscapes healthy.
So, if your plants have problems, please contact your local Extension Office. If they don’t know the answer, then the network of scientists, including plant pathologists, in the UF/IFAS Extension family can be called on for backup to provide you with the best possible answer.
by Beth Bolles | Jun 8, 2016
Gardeners love to share plants. My yard, like many of my gardener friends, is filled with plant gifts that were started from a cutting or division of a favorite plant. These two methods of growing new plants is fairly easy once you learn the techniques and allows gardeners a way to save a little money and grow more plants for their yard, special community projects, or even some fundraising events.
In our enthusiasm over a favorite plant, gardeners must be aware that we are not allowed to propagate certain plants from cuttings or division. Many of our ornamental plants, especially newer introductions are patented plants. These are seen as ‘premium’ plants that will hopefully be in demand by the public. The plant developer or nursery invests in the patent in hopes that the plant will become the next must have ornamental. Only businesses or individuals with authorization from the patent holder are able to asexual propagate these plants since the Plant Patent Act protects these new varieties for 20 years from the date of introduction.
So if you bought a beautiful Limelight hydrangea (Hydrangea paniculata ‘Limelight’ Plant patent #12,874) for your yard, you may not take a cutting to start a new plant, even if it is only for yourself.
If you want more than one Limelight Hydrangea, you must purchase it. Photo by Beth Bolles
When you visit the nursery, look on the plant label which will often indicate if the plant is patented. You may also look online to see if plant has a patent.
