A couple weeks ago, I was on a site visit to check out some issues on Canary Island Date Palms. The account manager on the property requested a site visit because he thought the palms were infested with scale insects. He noticed the issue on a number of the properties he manages and he was concerned it was an epidemic. From a distance, lower fronds were yellowing from the outside in and the tips were necrotic. These are signs of potassium deficiency with possible magnesium deficiency mixed in.
Transitional leaf showing potassium deficiency (tip) and magnesium deficiency (base) symptoms. Photo Credit: T.K. Broschat, University of Florida/IFAS Extension
Nutrient deficiencies are slow to correct in palm trees. It’s much easier to prevent deficiencies from occurring by using a palm fertilizer that has the analysis 8N-2P2O5-12K2O+4Mg with micronutrients. Even if the palms are part of a landscape which includes turf and other plants that require additional nitrogen, it is best to use a palm fertilizer with the analysis previously listed over a radius at least 25 feet out from the palms. However, poor nutrition wasn’t the only problem with these palms.
Upon closer look, the leaflets were speckled with little bumps. Each bump had a little white tail. These are the fruiting structures of graphiola leaf spot also known as false smut.
Graphiola leaf spot (false smut) on a Canary Island Date Palm. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
Graphiola leaf spot is a fungal leaf disease caused by Graphiola phoenicis. Canary Island Date Palms are especially susceptible to this disease. Graphiola leaf spot is primarily an aesthetic issue and doesn’t cause much harm to the palms infected. In fact, the nutrient deficiencies observed in these palms are much more detrimental to their health.
Graphiola leaf spot affects the lower fronds first. If the diseased, lower fronds are not showing signs of nutrient deficiencies then they can be pruned off and removed from the site. All naturally fallen fronds should be removed from the site to reduce the likelihood of fungal spores being splashed onto the healthy, living fronds. A fungicide containing copper can be applied to help prevent the spread of the disease, but it will not cure the infected fronds. Palms can be a beautiful addition to the landscape and most diseases and abiotic disorders can be managed and prevented with proper pruning, correct fertilizer rates, and precise irrigation.
Talk to nearly any Panhandle gardener and one of the first things brought up in conversation is the difficulty growing large, beefsteak/slicing tomatoes (Solanum lycopersicum) in their home garden. Large tomatoes are indeed among the more challenging garden vegetables in North Florida, affected by myriad pests, pathogens and abiotic issues. However, giving up growing this garden favorite is unwarranted as success can be had by following a couple of often overlooked, simple steps to ward off potential problems.
Choose Resistant Cultivars – One of the major recent gardening trends is the rise of heirloom veggies, particularly heirloom tomatoes. While many of these varieties certainly are interesting and often possess superior flavor/texture, heirlooms are, as a group, extraordinarily susceptible to disease in our climate. Fortunately for gardeners, there are a number of excellent varieties available with large resistance profiles to many common diseases and a similar taste profile to heirloom favorites! ‘Big Beef’ (pictured), ‘Better Boy’, ‘Celebrity’, and ‘Skyway’ are just a few of the many great cultivars with extensive disease resistance available as transplants at garden centers or as seed from quality online seed vendors.
Tomato ‘Big Beef’ in 15 gallon decorative container
Start Early – Once, you’ve selected the proper cultivar, the next key is to get them in the ground early! I’m convinced one of the primary reasons folks fail with tomatoes is waiting for “traditional” garden planting dates. For instance, an old tradition in the South is to plant your garden on Good Friday before Easter. However, according to Johnny’s Selected Seeds Southeast Sales Representative Blake Thaxton, tomatoes should be germinated and growing in the garden no later than March 15. Mr. Thaxton notes two primary reasons for this, the most important being pest/disease avoidance. Beefsteak tomato varieties take around 70 days from planting to harvest, so a March 15th planting date yields ripe tomatoes around the third or fourth week of May, when pest/disease pressure is still manageable. Pests and disease occurrence becomes exponentially worse in the Panhandle as May trickles into June and July, therefore it is critical that your fruit begin ripening prior to this onslaught. An important second motivation to plant early is that tomatoes stop setting fruit when nighttime temperatures rise above 75°F. At these temperatures, tomato pollen is rendered sterile and though the plant will continue flowering, no fruit will be set.
Mulch – Another overlooked best management practice in backyard veggie gardening is mulching! Those of us who tend flower beds already know many benefits of mulch like soil temperature moderation, weed prevention, and moisture conservation. But for tomato growers, mulch has another benefit – disease prevention! Several serious diseases that affect tomato are soil-borne pathogens (i.e. Early Blight, Late Blight, Bacterial Spot, etc.). These pathogens find their way onto plants either indirectly via water splashing from soil onto leaves or direct contact from leaves and fruit resting on the soil. To prevent these pathogens from infecting plant tissue, apply an organic mulch (preferably wheat straw or tree leaves) under and around plants. This simple step goes a long way toward season-long, yield-saving disease prevention.
Consistent Watering – Everyone knows plants need water but what you might not know is that irrigation consistency makes a huge difference in plant health, particularly tomatoes. Consistent watering is key in helping ward off one of the most frustrating tomato maladies, blossom end rot (BER) – you know, the one where the bottom end of your perfectly good tomato fruit turns to a brownish mush! Though BER is caused by calcium deficiency, the condition is commonly induced by creation of distinct wet and dry periods from non-regular watering, interfering with calcium uptake and availability to the plant. So, while you may have adequate soil calcium, if you don’t water correctly, the condition will happen anyway! It’s also good to keep in mind that mature tomato plants use large quantities of water daily, so during the heat of summer, plants in containers may need to be watered multiple times daily to maintain consistently moist soil. Think about it, you don’t drink 8 glasses of water when you wake up and then never drink again throughout a hot day. A tomato is no different. Allowing your plants to wilt down before providing additional water ruins productivity and can induce BER.
Tomato ‘Big Beef’ demonstrating pruning for soil clearance and airflow.
Pruning – I get it. Once you’ve nursed your baby tomato from a wee transplant or seed into a rapidly growing and flowering plant, it seems counter-intuitive to break out the pruners, but to keep your tomato plant as healthy as possible for as long as possible, that is what you must do! Pruning tomatoes should accomplish two things. First, remove the bottom layer of foliage from the plant base, so that water will not readily splash onto the lowest remaining leaves. (I tend to remove all leaves up to the second set of flowers 8-12” from the soil’s surface.) As with mulching, this prevents bacterial and fungal pathogens from spreading easily from the soil surface onto your plant. Second, tomato plants, especially the vigorous indeterminate varieties, often grow more foliage than is necessary for fruit production. This excess foliage can prevent airflow and trap moisture in the canopy of the plant, promoting disease. To open up the canopy and allow for more airflow, I prune off leaves that grow from the primary stems inward to the center of the plant. The idea is to keep the inside of the plant open while allowing enough leaves to power photosynthesis and shade the developing fruit below.
Tomatoes are notoriously hard to grow, but by following a few easy preventative practices, gardeners can greatly increase their chances of realizing harvestable fruit come summer. Please keep in mind that this is not an exhaustive list that will ensure disease-free plants over the entire growing season (you should also get a soil test to make sure your pH and soil fertility are correct and ideally you’d never work in your tomatoes when they are wet, etc., but this is a good place to start!). However, a little bit of planning and prevention early in the season can make growing tomatoes a lot less frustrating! As always, if you have questions regarding tomatoes or any other horticultural topic, please contact your local UF/IFAS Extension Office. Happy gardening!
Twisted and tangled kiwifruit plants in a North Florida orchard. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
When we think of kiwis, we think of fuzzy, slightly tart, egg-shaped fruits from somewhere in the Southern Hemisphere. However, there is a species (Actinidia chinensis) of kiwi with smooth skin, sweet taste, and golden color.
Commonly available cultivars of this species are ‘AU Golden Dragon’ and ‘AU Golden Sunshine’. Most years, kiwis won’t produce much of a crop in North Florida because they won’t receive enough chill hours, but they might be fun to try for the adventurous gardener.
- Site Selection – Kiwis perform best in well-drained soils with a neutral pH (around 7.0). High winds may cause canes to break and scar fruit, so a windbreak is recommended or they can be planted near a structure.
- Irrigation – Kiwis need a lot of water during the summer. This is partly due the their large leaves that transpire rapidly because of surface area. Newly planted kiwis should be watered deeply at least once a week.
- Fertilization – Fertilize kiwis three times a year (January, April, and June). Do not apply fertilizer after the month of July to reduce the incidence of cold injury in the winter.
- Insects and Diseases – The most common insects of kiwis are mites and scales. To reduce the incidence of disease, plant kiwis at least 15 feet apart and train on a trellis.
- Training – A T-bar trellis, similar to the system used to train grape vines, or a pergola should be used to provide support for the plants. Once the plants are established (2 to 3 years after planting), about a third of the vines should be removed each year.
An illustration of a T-bar trellis system. University of Georgia Extension
Kiwis are wind- and insect-pollinated. Good growing conditions and insect pollination help increase fruit size. Male and female plants are required for good fruit yields. At least one male (pollen producing) plant should be planted for every four female (fruit producing) plants.
Kiwi plants will soon be planted for evaluation at the West Florida Research and Education Center in Jay, FL. Please stay tuned for future data! For more information on growing kiwis in the Southeast, please visit these webpages:
Kiwifruit Production Guide
Bringing Home the Gold – Auburn horticulture alum gets kiwifruit orchard off the ground in Reeltown
Ice on Satsuma fruit from January 2014 ice storm in Crestview, FL. Photo credit: Larry Williams
Northwest Florida winters can be a rollercoaster ride of temperatures. One week it dips to freezing for a short time and the next week it rises to spring-like temperatures. We need to hold on for this ride of up and down temperatures but not over react too soon.
Following the sudden ride down to the lower temperatures, we may think winter is over. But we don’t see the next drop in temperatures that’s coming, as we are experiencing the ride upwards in temperatures.
On average, it’s not until we reach mid-March that we expect our last killing frost. A killing frost is heavy enough to kill tender plant growth. And, we can have light frosts well into the latter part of March and into early April. This is particularly true in the more northern portions of our Panhandle Counties.
The main point is to not get spring fever too early and encourage new plant growth by pruning or fertilizing too soon.
When landscape plants freeze, the first impulse may be to get out the pruning shears and cut away dead and dying leaves and branches. But this isn’t a good idea. Pruning can force new tender growth that is more likely to be injured by the next freeze. And, you can’t tell how much damage has been done until plants start new growth in spring. If you prune immediately after a freeze, you may cut away live wood that doesn’t have to be lost. Also, leaves and branches, which have been killed, can help protect the rest of a plant
Cold injury to lawn that happened March 31 in Crestview, FL. Photo credit: Larry Williams
against further cold injury.
Some people want to “jump start” their lawns before our weather will allow our grasses to grow. Waiting allows for more efficient use of the lawn fertilizer. You will not injury your lawn by
waiting but you can certainly injure your lawn by fertilizing too early.
So, have patience, allow your lawn to green up on its own and then fertilize, even if it’s not until April or May.
Finally, be a little philosophical. If you do lose one or two of your tender ornamentals, so what? Worse things could happen. And now you have a chance to add something new, perhaps some species native to our area that are not as subject to cold damage.
Even with this winter/spring rollercoaster ride, with thousands of plants to choose from and a generally mild climate, who can complain?
Fatsia japonica, common name Japanese aralia, provides tropical texture to your landscape. That coarse texture is attributed to its large (nearly a foot wide) leaves that are deeply lobed (maple leaf shaped). This shade-loving plant performs well in moist (not soggy) locations. Upright stems originate near ground level usually near the base of older stems. The stems grow to about eight feet tall before bending toward the ground under their own weight.
Even though the foliage of this species is enough to make you want it in your own garden, you will absolutely fall in love with its blooms. Upright clusters of showy, creamy white flowers begin to appear in fall. These little snowballs provide wonderful color to your garden. The shiny, black fruits appear in winter and are prominent for several weeks. The fruit are know to attract birds to the landscape.
A Fatsia japonica specimen in full bloom. Photo Credit: Matt Lollar, University of Florida/IFAS Extension
Fatsia japonica thrives in the shade in slightly acidic, nutrient-rich, moist soil. Older stems become leggy and can be cut back to encourage branching. In the right place, Fatsia japonica is low-maintenance and not typically bothered by pests. It is also known to perform well in coastal landscapes. It fits well in entryways, in containers, or in mass plantings spaced three feet apart.
After a devastating windstorm, as we just experienced in the Panhandle with Hurricane Michael, people have a tendency to become unenamored with landscape trees. It is easy to see why when homes are halved by massive, broken pine trees; pecan trunks have split and splayed, covering entire lawns; wide-spreading elms were entirely uprooted, leaving a crater in the yard. However, in these times, I would caution you not to rush to judgement, cut and remove all trees from your landscape. On the contrary, I’d encourage you, once the cleanup is over and damaged trees rehabilitated or disposed of, to get out and replant your landscape with quality, wind-resistant trees.
First, it’s helpful to take a step back and remember why we plant and enjoy trees and the important role they play in our lives. Beyond the commercial aspect of farmed timber, there are many reasons to be judicious with the chainsaw in the landscape and to plant anew where seemingly sturdy trees once stood. For example, trees provide enormous service to homes and landscapes, from massive cooling effects to aesthetic appeal. Take this thermal satellite image of Hurricane Michael’s path that simultaneously shows the devastation of a major hurricane and the role trees play in the environment.
Lightly shaded area showing higher ground temperatures from loss of vegetation.
In the lighter colored areas where the wind was strongest and catastrophic tree damage occurred, the ground temperatures are much higher than the unaffected areas. Lack of plant life is entirely to blame. Plants, especially trees, provide enormous shading effects on the ground that moderate ground temperatures and the process of transpiration releases water vapor, cooling the ambient air. Trees also lend natural beauty to neighborhood settings. There is a reason people termed the hardest hit areas by Michael “hellscapes”, “warzones”, etc. Those descriptions imply a lack of vegetation due to harsh conditions. In this respect, trees soften the landscape with their foliage colors and textures, create architecture with their height and shape, and screen people from noise, unpleasant sights and harsh heat.
Though all trees give us the benefits outlined above, research conducted by the University of Florida over a span of ten major hurricanes, from Andrew to Katrina, shows that some trees are far more resistant to wind than others and fare much better in hurricanes. In North Florida, the trees that most consistently survived hurricanes with the least amount of structural damage were Live Oaks, Cypresses, Crape Myrtle, American Holly, Southern Magnolia, Red Maple, Black Gum, Sycamore, Cabbage Palm and a smattering of small landscape trees like Dogwood, Fringe Tree, Persimmons, and Vitex. If one thinks about these trees’ growth habits, broad resistance to disease/decay, and native range, that they are storm survivors comes as no surprise. Consider Live Oak. This species originated along the coastal plain of the Southeastern United States and have endured hurricanes here for several millennia. Possessing unusually strong wood, they have also developed the ability to shed the majority of their leaves at the onset of storms. This defense mechanism leaves a bare appearance in the aftermath but allows the tree to mostly avoid the “umbrella” effect other wide crowned trees experience during storms and retain the ability to bounce back quickly. Consider another resistant species, Bald Cypress. In addition to having a strong, straight trunk and dense root system, the leaves of Bald Cypress are fine and featherlike. This leaf structure prevents wind from catching in the crown. Each of the other listed species possess similar unique features that allow them to survive hurricanes and recover much more quickly than other, less adapted species.
Laurel Oak split from weak branching structure.
However, many widely grown native trees and exotic species simply do not hold up well in tropical cyclones and other wind events. Pine species, despite being native to the Coastal South, are very susceptible to storm damage. The combination of high winds and beating rains loosens the soil around roots, adds tremendous water weight to the crown high off the ground, and puts the long, slender trunks under immense pressure. That combination proves deadly during a major hurricane as trees either uproot or break at weak points along the trunk. In addition to pines, other widely grown native species (such as Pecan, Laurel Oak and Water Oak) and exotic species (such as Chinese Elm) perform poorly in storms. Just as the trees that survive storms well possess similar features, so do these poor performers. We’ve already mentioned why pines and hurricanes don’t mix well. Pecan, Laurel Oak, and Water Oak tend to have weak branch angles and break up structurally in wind events. The broad spreading, heavy canopy of trees like Chinese Elm cause them to uproot and topple over. It would be advisable when replanting the landscape, to steer clear of these species or at least site them a good distance from important structures.
This piece is not a warning to condemn planting trees in the landscape; rather it is a template to guide you when selecting trees to replant. Many of our deepest memories involve trees, whether you first climbed one in your grandparent’s yard, fished under one around a farm pond, or carved your initials into one in the forest. Don’t become frustrated after a once in a lifetime storm and refuse to replant your landscape or your forest and deprive your children of those experiences. As sage investor Warren Buffett once wisely said, “Someone is sitting in the shade today because someone planted a tree a long time ago.”
For these and other recommendations about how to “hurricane-proof” your landscape, contact your local UF/IFAS Extension Office. Plant a tree today.