Pro Hort Series: Tree Pruning
Thursday, November 3, 8am-12pm. ProHort Series: Tree Pruning. Escambia County Central
Office Complex 3363 West Park Place Pensacola, FL 32505
Persimmon: A Dooryard Fruit
Image Credit: gardeningsolutions.ifas.ufl.edu
A recent visit to the North Florida Research and Education Center reminded me of a fruit that is often low profile in Northwest Florida, the Oriental persimmon. The Oriental, or Japanese, persimmon (Diospyros kaki) was introduced to the Southern United States in the mid to late 1800s. Although it is native to Japan and China, it is a close relative of the native persimmon Diospyros virginiana.
In the early 20th century the oriental persimmon was a popular fruit crop in Florida, but this industry declined due to marketing factors. The Oriental persimmon is still a viable fruit for home gardens.
Trees are available grafted onto local native persimmon rootstock, which enhances their ability to perform well in Northwest Florida soils.
Persimmons are divided into two types for the purposes of marketing: astringent and non-astringent. Astringent persimmons contain high concentrations of tannins which cause the mouth to pucker when eating the persimmon if it is not fully ripe. When fully ripe, they are rich and sweet, but very soft. Non-astringent cultivars can be picked hard and ripened for 7-10 days at room temperature. Non-astringent persimmons were developed in Japan and introduced to the U.S. market in the 1980s. These have become very popular with home gardeners since they can be eaten when firm, and have a crunchy texture. Persimmons are popular today in Asian cuisine and as a dessert, since they contain sugars at levels between 15 and 25%.
Persimmons have relatively few pests in Northwest Florida when compared to other higher maintenance fruits such as peaches and plums. Fungal leaf spot caused by species of cercospora, alternaria and anthracnose can cause premature defoliation. Fungicidal sprays are useful in controlling these diseases if they are at high enough levels to cause tree injury. The stem and branch fungus Botrysphaeria dothidia will cause deep, elongated branch lesions similar to canker. These openings invite borers into the tree and can lead to loss of the limb structure. The best defense against this problem is a good offense; a healthy tree will be less likely to be attacked by this fungus. Dormant sprays of copper or sulfur based fungicides can also help reduce the incidence of all fungal diseases.
Fully ripe persimmon, ready for a scoop of ice cream! (Image Credit Matthew Orwat)
The major insect pest of persimmon is scale. Thankfully, scale can be controlled with dormant oil or season all horticultural oil. Persimmon psylla can cause leaf deformation early in the season, but is not always a large enough problem to warrant control. Natural enemies often eliminate the need for chemical control. If control is necessary, several insecticides labeled for fruit trees will take care of the problem. Twig girdlers can lay eggs on persimmon stems in September and October, and once hatched, the insect can girdle the stem and the stem will die. To control this pest it is important to remove dead and infected wood each growing season.
Out of the non-astringent cultivars, Fuyu regularly rates as the most popular and reliable cultivar. It does require thinning, since it often sets too much fruit, which can cause branches to bend and break. A good practice is to thin out 50% of the fruit during years in which fruit set is heavy.
Below is a chart of different non-astringent persimmon cultivar characteristics from the IFAS Extension publication SP 101, from April 1994 by E.P. Miller, Biologist; T.E. Crocker, Professor, Horticultural Sciences Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida.
Characteristics of non-astringent cultivars. SP 101, from April 1994 by E.P. Miller; T.E. Crocker,
For further information please consult the UF / IFAS publication ENH 388: Diospyros kaki: Japanese Persimmon and the previous Panhandle Agriculture article Oriental Persimmon Varieties for North Florida .
How to Care for Palms After the Storm
Figure 1: Palm damage after storm event.
Credit: Edward F. Gilman, UF/IFAS.
A common question after a tropical storm or hurricane event is will my palm tree recover? Palms grow different from other trees, so there’s definitely a different way to care for them post-storm.
The growing point of a palm tree is the bud, located in the top of the tree. This is where the palm fronds emerge. If this bud area becomes damaged, no new leaves will develop and unfortunately the tree will die. If by chance the palm tree has multiple-stemmed trunks, the undamaged trunk(s) should survive. Often times palm trees are so tall that it is very difficult to visibly determine if the bud has been damaged. Time will tell.
It’s important to wait at least 6 months to see if palms develop new growth. Palms usually rebound slowly after a storm. It may take a couple of years before the palm tree produces a full canopy of fronds. If a damaged palm tree is determined to be in peril and current rainfall is not sufficient, it’s important to irrigate three times a week for at least six weeks to assist in recovery.
After the storm strikes, it may be beneficial to perform pruning of the canopy. Start by removing any hanging broken or dead fronds that could be hazardous to people or property. It’s a good idea to remove any fronds that are covering the bud, as well. This will allow new fronds to form. Leave any bent green fronts attached. These fronds still have vital nutrients that the tree is utilizing. Once the frond turns brown, then it is safe for removal.
Storm damage cleanup is extremely dangerous, even for professionals. During cleanup after the storm, remember that safety comes first. Some general safety tips are essential, as in, do not work alone. It’s important to keep a well-stocked first aid kit too. Avoid overexertion at all costs. This is the most common cause leading to injury. Be sure to survey the area, identify the hazards and have a plan for the cleanup. Above all, create a safe area to work within.
Palm tree recovery from storms is a slow process, so please be patient and safe. Contact your local county extension office for more information.
Supporting information for this article can be found in the following the UF/IFAS publications:
“Assessing Damage and Restoring Trees After a Hurricane” by Edward F. Gilman, Mary L. Duryea, Eliana Kampf, Traci Jo Partin, Astrid Delgado & Carol J. Lehtola: http://monroe.ifas.ufl.edu/pdf/Hort/Assessing_Trees_After_Hurricane.pdf
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Helping Turfgrass Overcome Herbicide Injury
Dr. Ramon Leon, Extension Weed Specialist, West Florida Research and Education Center
Herbicides simplify weed management by allowing you to cover extensive areas in a relatively short time, and reduce the need for time-consuming control practices such as hand weeding. Additionally, many herbicides have the advantage of selective control. Selective herbicides are those that kill weeds without significantly injuring the desired plant. In turfgrass, selective herbicides are particularly important because we do not have the option of using cultivation or non-selective herbicides, as is commonly done in other agricultural systems such as row crops and orchards.
A common misconception is that when a herbicide is registered for use on a given turfgrass species, this herbicide has little negative effect on the turf. In reality, even when the herbicide is registered for a specific turfgrass species, it can cause a certain level of injury. If the herbicide is applied at the recommended label rate, and the growing conditions are ideal, the turfgrass will only suffer minor, temporary injury that may go completely unnoticed. Conversely, the weeds that are susceptible to the herbicide will be severely affected resulting in the desired control.
Over the last few summers, there has been an increase in complaints about herbicide injury on sod farms, golf courses, and home lawns after applications of herbicides, especially during the summer months. Many of those complaints originated from situations in which the application was done properly, using the recommended label rate, and thus the level of injury observed was not justified. After studying all these cases, it was determined that at the time of herbicide application the turf was under a moderate level of stress, but not high enough stress to cause visible symptoms. However, when the herbicide was applied the combined effect of the existing stress, and the stress caused by the herbicide made it harder for the turf to maintain the desired quality. For example, Figure 1 below shows that the turf looked fine before the application (A), but after the herbicide was applied, there was a significant loss in turf cover and quality (B). The interesting aspect is that the injury was not present across the entire treated area, but only on patches (C). Those patches corresponded with sand pockets where soil moisture, especially on hot days, was considerably lower than the rest of the area. In that particular case, the irrigation system was providing enough water to help the turf tolerate the moderate stress of high temperatures and limited moisture, but not enough for the turf tolerate the combined stress that occurred after the herbicide was applied.
Figure 1. Centipedegrass growing during the summer in Florida before herbicide application (A), 3 weeks after herbicide (sulfentrazone and metsulfuron-methyl) application (B). Herbicide injury pattern with highlighted areas showing where sand pockets caused drought and heat stress that contributed to herbicide injury (C).
In Florida, there are a combination of environmental factors such as high temperatures and sandy soils that can create stressful conditions limiting turfgrass growth, especially when irrigation is not sufficient to keep the turf hydrated. Furthermore, we also experience periods of excess rainfall, and areas of turf growing under shade. Additionally, pest problems that affect roots and leaves are frequently found in our state. All these conditions affect turfgrass health and its ability to tolerate herbicide applications. For these reasons, turf producers and managers need to be proactive to help turfgrass overcome the injury that herbicides might cause. To achieve this goal, you need to follow five simple steps:
1) Identify weed problems early. Most weed problems will start in the spring for summer weeds and in the fall for winter weeds. Controlling them when they are small not only increases the effectiveness of our applications, but also allows us to implement our control when the turfgrass is less likely to be stressed.
If herbicide applications are needed when conditions might be stressful for the turf (high temperatures and/or dry conditions)
2) Make sure irrigation is adequate (increase frequency or duration if needed) for up to three weeks following application.
3) Reduce mowing frequency and increase mowing height 0.5 inches for up to 3 weeks following a herbicide application, to allow the turfgrass to continue producing energy to support its recovery. Mowing too short and too frequently immediately after the application weakens the turfgrass.
4) Fertilize with a small amount of nitrogen (0.25 to 0.5 lb N/acre) a week or two after herbicide application to help the turf recover and produce new leaves.
5) If the turfgrass is suffering from serious pest problems (pathogens, nematodes or insect infestations) do not apply herbicides on the affected areas until the turfgrass has recovered.
Maintaining optimal turfgrass growth is the best way to ensure that herbicide applications will maximize weed control while still protecting the health and aesthetics of your turfgrass.
For more information on growing turfgrass in Florida, please see the following:
Florida Lawn Handbook
Dr. Ramon Leon, Extension Weed Specialist, West Florida Research and Education Center
Spiny Spiders
The year’s mild winter and frequent rain showers have created lush lawns and gardens with an abundance of insects. As a result, we are seeing many predator arthropods taking advantage of the available feast. One of the morning interesting creatures in the garden is the spiny orb weaver spider (Gasteracantha cancriformis) that has an interesting body shape.
Spiny orb weavers are common spiders in landscapes that might not be noticed since they are much smaller than the Yellow garden spider (Argiope aurantia) and the Golden silk spider (Nephila clavipes). Once viewed, the spiny orb weaver will catch your attention because it’s abdomen has six ‘spines’ or points that extend out. Spiders also have a mix of yellow, white, red, or black marking on the abdomen.
Spiny orb weaver in the center of the web waiting for a meal. Photo by Beth Bolles
Although spiders are small, the webs which are common amongst shrubs, trees, and edges of woods become quite substantial in the fall. There may be up to 30 spirals that extend out with the spider situated in the center. You may unexpectedly encounter a web when walking through the garden or mowing around trees and shrubs. There is no worry if a spider accidently gets on you as bites are not common and not considered serious.
Spider working on her web. Photo by Beth Bolles
Some may refer to the spiny orb weaver as a crab spider based on its shape, but it is a web building where the true crab spiders are active hunters often found resting on flowers in order to ambush a meal.
Enjoy our fall weather and look out for this beneficial spider in your landscape.