Ornamental landscape plants are broadly grouped into two categories: woody ornamentals and herbaceous ornamentals. Woody plants usually have larger root systems than herbaceous plants and are more likely to interfere with septic drainfields.
Install woody plants an appropriate and safe distance from the septic drainfield. A good rule of thumb is to use the ultimate mature height of the selected tree as the minimum planting distance from the septic drainfield, then increase the distance. For example, if you are planting a crabapple, plant the tree at least 25 feet from the nearest drain line; 50 to 75 feet would be even better. Consider planting smaller and less aggressive cultivars, if possible.
Herbaceous plants, on the other hand, die back to the ground during the winter and include annuals, perennials and turf. Perennials, including turf, will return the next year from their roots, but annuals will have to be planted fresh each year. These plants are usually smaller in size and their root systems tend to be shallower and less aggressive than those of woody plants.
Both woody and herbaceous plants can be used when landscaping on septic drainfields as long as a few guidelines are followed. Remember that septic drainfield lines are often very shallow, some no more than 6 inches from the surface. Excessive digging, rototilling or other methods of soil preparation for planting can damage these lines.
Don’t choose plants that typically thrive in wet locations. When tree roots invade these septic drain lines, the extra moisture and nutrients favor root and plant growth, and lines become clogged and damaged.
Source – Will Hudson and Kris Braman, UGA Extension Entomologists
Azalea lace bug and injury, Pest and Diseases Image Library, Bugwood.org
Azalea lacebugs overwinter as eggs and hatch in the spring. Early spring is a good time to control them before they become too numerous.
Azalea lace bug attacks azaleas and some rhododendrons. Azalea lace bugs mainly feed on the undersides of the leaves, leaving the top of the leaf with white to yellow stippling or flecking. Heavy lace bug feeding on azalea can reduce plant vigor and flowering and affects the overall look of the plant.
Adult azalea lace bugs are 1/8 inch long. The transparent wings are held flat on the back. Their wings are lacy with two grayish-brown cross-bands connected in the middle. Nymphs begin life clear but quickly turn black and spiny. The flask-shaped eggs are partially embedded in leaf tissue, usually on the bottom of the leaf, and often are covered with a black tar-like secretion.
Look for the first signs of damage on plants in full sun or in protected areas beginning in March and continuing throughout the summer. Lace bugs overwinter as eggs. There are four generations a year. Lace bug adults and nymphs live and feed on the underside of leaves. Look for white stippling on older leaves. Look under leaves to find lace bug life stages and black fecal spots. On azaleas with a lot of damage, the top of the leaf can become grey or silvery.
Azaleas can withstand a lot of lace bug injury without much reduction in growth or bloom. The damage however on the leaves is unsightly. Control is generally recommended for the spring when insects are few in numbers. Treating early also protects the new leaves from damage from these insects. Once a leaf is damaged, the injury will be visible until the leaf falls off the plant.
Time spring insecticide applications for the presence of the first generation nymphs, usually with the early warm weather in late February in south Georgia through March and April in central and north Georgia.
Late summer insecticide applications are also helpful. Lacebugs overwinter as eggs and managing adults now reduces the number of eggs on plants and the number of lacebugs you will see next spring. Once lacebugs are in the egg stage, insecticides will not effectively manage them.
Cultural controls for azalea lace bugs
Plant azaleas only in partial shade. Too much sun stresses the plant and can make lace bug injury worse.
Keep plants healthy with proper planting, fertilizing and watering.
One of the best things you can do is scout azaleas (particularly early in the season) to identify and control infestations before numbers increase and leaf damage is severe.
Chemical Controls
Contact insecticides include the pyrethroids (bifenthrin, cyfluthrin, cypermethrin, permethrin, etc.) and carbaryl (Sevin and others) as well as other insecticides.
The biggest concern with contact insecticides is getting full coverage. The chemical must be applied to the underside of the leaves. This is difficult with larger, fuller plants.
You may need to make more than one application for full control. Check plants three to four weeks after the first application to see if they need another treatment. Knocking the branches over a white piece of paper should dislodge the lace bugs and make them easier to see.
Systemic insecticides
Some systemic insecticides may be used as soil applications (liquid drenches and granular treatments) as well as sprays. Soil applied insecticides enter through the root system and then travel into the leaves.
Foliar sprays of systemic insecticides tend to work more quickly than soil application but soil applications give a longer residual control – up to several months.
Even though some soil applied systemic insecticides may take two weeks or longer to become active in the leaves of large plants, this is not a problem if plants are small or if application is made early enough in the season to provide protection for the first flush of new leaves.
Read and follow all label directions since systemic insecticides differ in the way they work in the plant.
For more information:
For pest management information see the Pest Management Handbook (Follow all label recommendations when using any pesticide)
Seasonal color plantings can often appear healthy and beautiful one day and absolutely awful several days later. Total collapse at planting is not uncommon. Even though the chief culprit may be a particular disease, there are usually multiple causes at the root of the problem, all leading to plant demise.
Landscapers can reduce disease pressure in color beds by proper care:
Figure 2. Mixed planting and improper crop rotation in two consecutive years. The petunias are exhibiting signs of disease in the first year (upper photo) as well as the second year (lower photo).
Prepare the soil in the beds to ensure both adequate water retention and drainage by incorporating several inches of organic matter each year.
Install annuals at a proper depth to avoid stressing root systems.
Remove old materials and spent blooms as much as possible to reduce disease inoculum.
Use water sensors on irrigation systems to provide water when it is needed, not on a specific schedule.
Choose water delivery methods, such as spray emitters directed at the base of plants, soaker hoses and drip irrigation, that will keep foliage dry.
Avoid planting the same species and cultivar of flowering crop, or crops belonging to the same family, in the same bed for more than two years. For example, petunias should not be followed with petunias because certain pathogens specific to petunias tend to accumulate and persist in the soil from year to year (Figure 2). Additionally, if ornamental tobacco is planted after petunia, it still could lead to plants being attacked by the same pathogens because the crops are closely related. This is of particular concern if the petunias were experiencing problems in the first year, which means that the pathogen is already in the soil and in sufficient quantity to cause damage.
Use the following list to select plants from different families to plant in successive years:
Common annual flowering species and their corresponding botanical family.
According to Science Daily, new research shows that imidacloprid, an insecticide often blamed for the decline of commercially managed honey bees, is not likely to harm honey bees at field realistic levels. The three year study, conducted by Galen Dively and associates at the University of Maryland, supports the contention by many U.S. bee researchers that proper applications of this insecticide is not likely to be the sole, or major, explanation for colony collapse disorder (CCD).
Despite those who claim CCD is clearly the result of dangerous insecticides, the issues surrounding CCD are complex and technical. Much of the debate in the research community recently has centered on what constitutes “field realistic levels” of imidacloprid and its cousin insecticides, the neonicotinoids. Industry representatives have contended that recent critical studies, cited by environmentalists as justifying a ban neonicotinoids, were flawed because they were based on unrealistically high levels of the insecticides. Dively and colleagues tried to allay these concerns by feeding their bees imidacloprid in protein supplement patties at doses of 5, 20, and 100 micrograms per kilogram (parts per billion). The lowest dose, 5 parts per billion, is generally recognized as field realistic based on several studies of pesticide concentrations in the nectar and pollen of treated crops. The insecticide-laced protein supplement was provided to the bees over a continuous 12 week period. Even so this was, the authors contend, a higher exposure scenario than would likely occur in agricultural settings, where the contaminated pollen and nectar is not likely to be present continuously.
As one of the first studies to look at honey bee colony health over multiple seasons, the results were more rigorous than previous research. They did showed a significant negative effect on colony survivorship as dosage increased; however the lowest, field-realistic dose showed no significant impact on key bee health indicators, foraging or winter survivorship. The major impact of higher imidacloprid exposure were increased broodless periods, caused by weak queens during late summer. Such effects could lead to lowered overwintering survival, a character of CCD.
Nevertheless, the authors conclude that while short term exposure to high imidacloprid levels (represented by 100 part per billion dosages in this study) in agricultural settings does occur, it is not likely to occur continuously throughout a crop cycle. Also, data from the study showed that bees were efficient in metabolizing imidacloprid, so that short term spikes in insecticide levels in nectar were likely to be quickly diluted and eliminated by the bees. They concluded that while imidacloprid might be a contributing factor to some overwintering losses in bees, seed treated crops in particular were likely to have negligible effects on honey bee colony health.
In the ongoing debate over bee health, this is one piece of good news for pesticide manufacturers and users; but it will not be the final word. And it should not justify anything less than the utmost caution for pesticide applicators when they use neonicotinoid insecticides.
The National Weather Service has a good graphical forecast tool for hourly weather variables available on their web sites. You can get instructions for how to get one for your location at http://www.srh.noaa.gov/oun/?n=hourlyweathergraph.
The forecast has a number of parameters to choose from, including temperature, wind, humidity, rain and other forms of precipitation, thunder, and a variety of fire weather variables that you might need if you plan to do controlled burns.
The output of the forecast depends on what parameters you pick but generally looks like the image below. The forecasts go out to six days from present, which should give you ample time to plan activities which are weather-dependent, like spraying pesticides or cutting hay.
Many of the private forecasting firms also provide hourly forecasts on their websites and using their apps on smartphones and tablets.
Phenoxy herbicide damage to a willow oak tree. Image credit: Paul Pugliese.
Paul Pugliese is the agriculture & natural resources agent for the University of Georgia Extension office in Bartow County.
An herbicide designed to kill weeds in turfgrass can also kill neighboring trees and shrubs.
Herbicides in the phenoxy chemical class provide broadleaf weed control in lawns, pastures and hay forages. Some of the more common chemicals in this class include 2,4-D; MCPP; dicamba; clopyralid; and triclopyr.
Safe for animals but not always for trees and shrubs
These chemicals are considered very safe and leave very few toxicity concerns for animals. In fact, many of these herbicides are labeled for pasture use and allow for livestock to continue grazing without any restrictions.
Phenoxy herbicide damage to a willow oak tree. Image credit: Paul Pugliese.
However, pesticide labels should always be read and followed to determine if any special precautions should be taken for specific site uses.
Phenoxy herbicides provide selective weed control, which means they control many broadleaf weeds without causing damage to grass. Of course, each product is a little different and some are labeled for very specific turfgrass types, depending on their tolerance.
The label should be checked for application to a specific lawn type (tall fescue, bermudagrass, zoysiagrass, etc.). If the turfgrass isn’t on the label, don’t assume the herbicide can be applied to all lawns.
Unfortunately, phenoxy herbicides don’t discriminate between dandelion weeds or any other broadleaf plants, including many trees and shrubs. So, it’s very important to take extra precautions when applying these herbicides near landscaped areas with ornamental plants.
Wind and rain can spread herbicides
Consider the potential for drift damage to nearby plants and avoid spraying herbicides on a windy day. There is also the potential for movement of these herbicides through runoff and leaching in the soil. This is why the product label usually warns against spraying within the root zone of trees and shrubs and never exceeding the maximum application rates listed on the label.
Many homeowners and landscapers often overlook these label precautions. The information that is contained on the label can seem somewhat vague to inexperienced applicators.
The biggest misconception concerns where the root zone of a tree or shrub exists. The roots of mature trees and shrubs actually extend well beyond the drip line of the canopy. Research shows that absorption roots may extend as much as two to three times the canopy width.
Consider spot-spraying to target individual weeds rather than broadcasting applications across the entire lawn. And never exceed the labeled rate.
In landscapes that contain mature trees and shrubs, phenoxy herbicides may not be the best choice for weed control. These herbicides may be best reserved for wide-open spaces such as athletic fields, parks and pastures where tree roots are at a safe distance.
The high potential for herbicide damage to trees is another great reason to protect tree roots by providing a mulch zone that extends well beyond the drip line of the canopy. If you’re not trying to grow a manicured lawn underneath a tree, then there is no reason to apply phenoxy herbicides there for weed control.
Use the right herbicide for the job
Another way to avoid potential damage is to rely less on phenoxy herbicides. Other classes of herbicides have less potential to affect the roots of nearby trees and shrubs. Take the time to identify your weeds and choose a more selective herbicide rather than combination products that usually contain multiple chemicals in the phenoxy class.
Many pre-emergent herbicides can prevent weed problems in lawns. The key is to apply them at the correct time in spring and fall. Applying too early or too late often provides inadequate weed control and requires additional herbicide applications. Rotating pre-emergent herbicide classes will avoid the potential for resistant weeds. Also, be sure to apply water to the area according to the pre-emergent herbicide’s label to activate it in the soil.
For more information about the effects of phenoxy herbicides on landscape trees and shrubs, view the UGA Center for Urban Agriculture webinar at ugaurbanag.com/webinars. For assistance with weed identification and specific herbicide recommendations, contact your local UGA Extension office at 1-800-ASK-UGA1 or visit www.Georgiaturf.com.
Rank growth of winter annual weeds occurs at the same time that warm-season turfgrasses begin to green-up, or emerge from winter dormancy. These weeds compete with the turfgrass for soil moisture, nutrients, growing space, but most importantly for sunlight. Warm- season turfgrasses, with the exception of St. Augustinegrass, are not highly shade tolerant. Thick mats of winter weeds will shade the turfgrass at a time that root carbohydrates are being exhausted by the green-up process. Additionally, thick mats of winter weeds shade the turfgrass and decrease photosynthesis. The net result is a weakened, or less dense stand of turfgrass, that is readily infested by summer annuals such as crabgrass.
Purple Deadnettle, Robert Vidéki, Doronicum Kft. Bugwood.org
Preemergence herbicides
Research has shown that the preemergence herbicides, such as Balan, TeamPro, Surflan, XL, Ronstar and many others, that are used for summer annual grass control do not significantly affect the spring green-up of labeled warm-season turfgrasses. A possible exception is Pennant (metolachlor). There have been some significant delays in the green-up of hybrid bermudagrass with Pennant applications to dormant turf.
Postemergence herbicides
The situation with postemergence herbicides is dramatically different. Most postemergence herbicides will slightly delay the early spring growth of warm-season turfgrasses. These delays can range from a few days to a few weeks.
In the event of an overdose (an extremely high rate), delays in spring green-up can occur for a longer period of time. Usually, the turfgrass will completely recover within two to six weeks with proper cultural management.
With the exception of Image, most postemergence herbicides can safely be used during green-up. Some slight delay in green-up may be noted; however, this effect can be lessened by:
Using the lowest recommended rate
Insuring that the application equipment is properly calibrated
Using spot treatments
Following all recommended cultural practices, fertility, irrigation, etc. to promote rapid spring growth.
The use of postemergence herbicides should be avoided during the spring green-up of turfgrasses that have been poorly managed, or that are experiencing winter injury problems. Properly maintained, healthy, vigorous turfgrasses are more tolerant to postemergence herbicides than turfgrasses that have not been properly maintained or are suffering from winter injury.
Some postemergence herbicides state on the label “Do not apply during spring green-up.” Obviously, these products should not be used at this time of year. However, the use of other postemergence herbicides is warranted if there is a severe weed infestation on properly maintained turfgrasses. The slight delay in green-up from the use of these herbicides is more than compensated for by the removal of competition that dense mats of weeds exert on the turfgrass.
As always – read and follow all pesticide labeling directions!
Fire ants remain the most prevalent outdoor ant pest in most areas of the southern U.S. Throughout the U.S. we estimate the annual cost of fire ant control at over $6 billion. But the cost of this pest goes far beyond measurable dollars. Fire ants reduce the recreational value of our parks and backyards, disrupt wildlife populations, and send thousands to emergency rooms each year from their painful stings.
So as we get ready to enter fire ant season, it may be a good time to bring yourself and your staff up to speed on fire ant control. Many people are surprised to learn that fire ants are not an especially difficult pest to manage, once the biology and control tools are understood.
One of the best places to learn about fire ant management is the eXtension fire ant website, a place where the best information about fire ant is assembled by Extension agencies throughout the South. This information was recently summarized and presented in an informative webinar by Dr. Fudd Graham, fire ant specialist with Auburn University. Dr. Graham focuses on fire ant biology and use of baits for fire ant control.
It’s worth knowing something about how fire ant baits work because they are the most economical, ecologically friendly, and effective control methods for fire ants. The webinar will provide you or your technician with an hour of training that should pay for itself many times over.
Mike Merchant is an entomology specialist for Texas AgriLife Extension. He works with pest management professionals, school facilities managers, extension volunteers, researchers and other extension professionals. His areas of specialty center on research on insects affecting man including spiders, scorpions, fire ants, termites and others. His program also focuses on training school maintenance professionals in principles of integrated pest management (IPM). His goal is to make schools healthier, cleaner places to study and live.
We invite you to apply or advise a horticultural student of the benefits of this scholarship. Scholarships are awarded, through a competitive process, administered by a selection committee based on academics, character, determination, probability of a career in horticulture, and financial need.
In 2014, twelve $1,500 scholarships were awarded, totaling $18,000. The number and amount of scholarships awarded each year is determined by the board of directors based on the fund’s income (interest and dividends) from the previous year.
Scholarship applications for the 2015 year a now available. Deadline for application is May 29th. Selections will be made by July 1, and recipients will be notified soon thereafter. Awards will be made July 22 in Atlanta during SNA2015.
Please refer to the eligibility requirements, and download the 2015 Application below, or call the Fund office at 678.813.1880 to receive an application via email attachment, fax or regular USPS mail.
Now that spring is here and warmer, more humid air is entering the US, severe weather and tornado chances are increasing across the country. There is an excellent animation that shows how the region of severe weather occurrence moves around the country at the NOAA Storm Prediction Center. The area of most likely severe weather moves north and south with the area of greatest temperature contrast and most active storm track as the sun’s angle changes over time.
The Weather Channel has also provided a series of bar graphs which show the monthly probability of tornadoes for over 40 cities around the country (link). From the graphs you can see that the Southeast has a split severe weather season, with the major peak in spring and a secondary peak in late fall.
And make sure you have access to real-time severe weather warnings via smartphone app or NOAA weather radio, especially if you are working outside on high-risk days.
