by Carrie Stevenson | Jul 19, 2016
Florida home and yard. Home, house, stone pavers, walkway, yard, landscaping. UF/IFAS Photo: Tyler Jones
Dr. Ramon Leon, Extension Weed Specialist, West Florida REC, Jay
Last year the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) classified glyphosate as “probably carcinogenic to humans.” This generated a lot of controversy because the Environmental Protection Agency (EPA), the European Food Safety Authority, and recently a joint report between the Food and Agriculture Organization (FAO) and WHO concluded that glyphosate is unlikely to be carcinogenic in humans.
As a University of Florida/IFAS Weed Specialist, I have been receiving multiple phone calls and e-mails from homeowners, homeowner associations (HOA), lawn care companies and contractors, municipalities, and county managers requesting a list of herbicides that are “safer” than glyphosate. When I ask them the reason for this particular preference, all of them acknowledged that their concern originated from hearing about the IARC report.
The first point that I always explain to people concerned about this issue is that most of the scientific evidence indicates that glyphosate does not have a higher carcinogenic risk compared to many other substances that they are normally exposed to in their daily activities. The second point is that it is important to continuously monitor how chemicals we use affect our health and the environment in the long run. The IARC report is a reminder that we should keep a close eye on glyphosate, the most widely used herbicide in the world, but it is not necessarily a call to stop using it, because at this point there is no direct evidence that it causes cancer in humans.
Very frequently, regardless of the technical details, many homeowners and citizens in urban areas are considering not using glyphosate in their gardens and landscapes, and they would like to use “safer” herbicides.
What do you mean by “safer?”
If you mean lower risk as a carcinogen, then most herbicides registered for use in urban areas would be acceptable because none of them are considered “probably carcinogenic” by IARC or any other regulatory agency. Therefore, you have multiple options to choose from. However, many of the conversations have lead to the statement, “No, I want something that is less toxic than glyphosate!”
Toxicity in pesticides is predominantly assessed using the lethal dose 50 (LD50), which indicates the amount of a chemical that kills 50% of a reference population of test animals (e.g. mice, rabbits, rats). When the LD50 is high, this means that the chemical has low toxicity, and when the LD50 is low it is considered that toxicity is higher because small amounts of the chemical can cause mortality. Glyphosate has one of the highest LD50s for herbicides. In other words, glyphosate is one of the least toxic herbicides available based on the LD50 standard. Therefore, if we want an alternative herbicide that is less toxic, we do not have any options for urban areas.
What about organic herbicides?
Many people associate “organic” with “safer.” This can be misleading because it depends on how safety is measured. For example, there are multiple organic herbicides that are considered to have the same or even higher toxicity when compared with glyphosate, because many of them have irritant and corrosive properties. Furthermore, organic herbicides have dramatically different herbicidal properties that make them unlikely alternatives to effectively replace glyphosate.
Glyphosate has one of the broadest spectrums of control, so it kills many different weed species effectively. Also, glyphosate works systemically. This means that it is absorbed by leaves and then moves inside the plant to growing points, roots, and other propagating structures. This systemic effect increases the ability to kill relatively large plants. In contrast, the majority of organic herbicides have a contact effect, so they only kill the tissue they touch without being able to move inside the plant. Therefore, they are effective at killing very small plants (<2 inches tall). Large plants can suffer leaf burning after treatment with organic herbicides, and if the application is done properly, the user will see a lot of control shortly after the application (Fig. 1). However, the plants will soon recover and the control level will decrease because, unlike plants treated with systemic herbicides, they can produce new growth from tissues that were not directly expose to the herbicide.
Figure 1. White clover (4 inches tall) control after treatment with glyphosate and twelve different organic herbicides based on natural oil extracts from plants. The green bars represent the level of control 7 days after treatment (DAT) and the yellow bars indicate control 21 DAT.
Considering the lack of alternatives to replace glyphosate, if you want to stop using this herbicide, and you do not want to use any other synthetic herbicides, because their toxicity might be higher, then you need to recognize that weed management will be more challenging. It is unfair to ask lawn care companies or members of HOAs to stop using the tools they have to control weeds and yet expect “weed free” lawns, gardens, and landscapes. Controlling weeds in these scenarios without glyphosate and other synthetic herbicides will require more intensive use of mechanical control approaches and hand weeding. Also, if relying on organic herbicides, these herbicides will have to be frequently applied (probably once or twice a week) in order to kill the weeds at the right time (before they get too big). Also, all these activities will increase weed control costs and the results will likely be not as satisfactory. Thus, you might end up paying more to have lawns and landscapes that will have more weeds escaping control. If this is not acceptable to you, then you probably should be more open to consider the weed control tools we have available. Also, you should be more vigilant about what are the appropriate ways to use them to minimize their risks to humans and the environment, while obtaining the benefits that you are seeking. Otherwise, you should get used to seeing more weeds in the landscape, and to be fair… this might not be as bad as some people think.
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.
by Daniel J. Leonard | Apr 27, 2016
People are, by nature, skeptical. Humans are and have always been questioners of the world around them and that’s a good thing! For instance, when one reads a sensational article on Facebook or watches an infomercial selling a too-good-to-be-true product he/she is immediately dubious of the veracity of the claim. Given this innate sense, why do consumers take plant tags displayed on retail plants and the information listed there as infallible fact when in reality they are often full of hyperbole and misleading?
I do not mean to insinuate that nurseries and landscape professionals are intentionally leading consumers astray. They are not. However, there is much incorrect information disseminated to consumers by the green industry on plant fact sheets. Take my titular example, ‘Little Gem’ magnolia is widely advertised and sold as a “dwarf” magnolia, only growing 15’-25’ tall. If given proper care, it will grow to that height…in seven to ten years. Given enough time, ‘Little Gem’ has will grow in excess of forty feet. People plant this cultivar under the eaves of single story houses on a regular basis! I promise that cute little magnolia you were told would grow 15’ tall will look rather silly when it is four times the height of your house. Take another example, how many times have you seen or heard of ‘Acoma’ crapemyrtle being sold as a “semi-dwarf” cultivar that grows to 10’ in height for use in a tight spot of the landscape in lieu of the much larger ‘Natchez’? It will fill that tight spot and fill it rather quickly. ‘Acoma’ can easily reach 20’ in height and width at maturity, engulfing its intended area.
Typical plant tag. Notice the “Average Size” section. This is where consumers should use discretion.
So why does this happen? Why are plant tags so often mistaken? There are two primary reasons that correct mature sizes are not given. First, in the competitive world of plant breeding and introduction where there can be hundreds or thousands of cultivars of a single species, it is of utmost importance to introduce plants as quickly. Quick introduction is necessary because others are probably working to find similar traits; therefore, if one notices that a plant possesses a drastically different flower, flowering pattern, leaf shape, leaf size, or growth habit, the plant is often rushed to market. This leaves little time for complete trials of the plant to see what it would look like at maturity.
Secondly, most well-adapted or native trees/shrubs have relatively long life spans. A crapemyrtle or magnolia can easily grow and thrive in a landscape for thirty years or more before reaching maximum size. Nurseries simply do not have time to evaluate plants that long. Many nurseries, due to vagaries of economic cycles and length of career spans, don’t even exist for thirty years much less trial a single plant for that length of time!
In conclusion, nurseries are not likely to change their plant tag practices, but there are a couple of checks consumers can use to make sure they buy an appropriate plant for the scale of their site. First, it is a good rule of thumb to double the advertised plant height to arrive at a better idea of the plant’s mature size. Second, drive through established neighborhoods and observe what certain plants look like in a mature landscape. This will give one an idea of what the plant is capable of. The third and best option is to consult your local County Extension Office. They will be able to offer research-based information to help you make the right decision in your plant choices. Keep this in mind the next time you are thinking of buying the latest, greatest plant at your local nursery!
Happy Gardening!
by Julie McConnell | Mar 28, 2016
Clusters of tiny white flowers on abelia. Photo: Julie McConnell, UF/IFAS
Abelias have been a landscape staple in the Southeastern United States for over a century. Numerous types have been used over the years, but two of the oldest forms still used in landscapes are Glossy Abelia Abelia x grandiflora and Abelia ‘Edward Goucher’, dating back to the early 1900s.
Glossy Abelia is a large informal shaped shrub with ½ – 1 inch glossy green leaves and large clusters of tiny white flowers. It can grow to 8 feet wide and tall and tolerates tough landscape sites such as full sun, low moisture (once established), acidic or slightly alkaline soils. It blooms prolifically and is attractive to butterflies and pollinators. New stems are reddish colored which contrasts nicely with dark green foliage which may be evergreen if winters are mild. After blooms are spent the pink sepals remain on the plants carrying more color through the season.
‘Edward Goucher’ Abelia does not grow quite as large and is a good performer with pink flowers. It is smaller than Glossy Abelia, but can still reach 5’x5’ when mature. It is also tolerant of hot, dry spots in the landscape.
Over the past few decades there have been many new introductions of abelia cultivars to the market. A major goal of breeders was to offer abelias that would fit into smaller landscapes and there has also been a trend towards variegated foliage color. There are dozens of abelias in production, but a few listed below are usually easy to find in local garden centers and have proven reliable in Florida landscapes.
- Abelia x ‘Rose Creek’ Rose Creek Abelia, low mounding growth habit reaching 2-3’ tall and 3-4’ wide, green foliage, new reddish stems, large clusters of white flowers
- Abelia x grandiflora ‘Hopley’s Lemon Zest™’ Lemon Zest Abelia or Miss Lemon™ Abelia grows 3-4’ tall and wide, has yellow and green variegated foliage, light pink flowers
- Abelia x grandiflora ‘Confetti’ Confetti® Abelia, matures at 3’ tall and wide, new foliage has pink, white, and green variegation and mature foliage is green and white variegated, pink and white flowers
- Abelia x grandiflora ‘Kaleidoscope’ P.P.#16,988 Kaleidoscope Abelia, compact growth 2-3’ tall by 3-3.5’ wide, gold and pink new foliage that matures into gold and green variegation, white flowers
All abelias perform best in full sun to part shade and have low water requirements once established. They are not salt tolerant, so avoid planting in coastal landscapes or in areas where salts are an issue. Abelias have few pest problems, but aphids have been known to feed on new growth – avoid over fertilization.
by Carrie Stevenson | Mar 2, 2016
Even large, healthy oaks may fall during a tornado. Photo credit: northescambia.com
When we think of bad weather in Florida, hurricanes are typically the first thing that comes to mind. In reality, Florida is 4th in the nation in tornado frequency—and when adjusted for frequency per square mile, we are actually number 1. Residents of Escambia County are believers now, as the community reels from enduring two tornadoes in the span of a week. Both rated as EF3 storms, the winds in the twisters (136-165 mph) were nearly equivalent to a Category 4 or 5 hurricane. The western Panhandle and much of south Alabama were under tornado watches as the most recent band of thunderstorms moved through.
Based on a thorough study of surviving trees after hurricanes in Florida, there are several species of trees best suited to windstorms. For north Florida, some of the top species are: Florida scrub hickory, several native holly species, Southern magnolia, sand live oak, myrtle oak, and bald and pond cypress. Data from the full study and an in-depth overview is available from the University of Florida. To prepare for a heavy thunderstorm or a milder hurricane, it is wise to replace or plant trees with the most wind-resistant species. Because of the damage from falling trees in storms, many homeowners are nervous about planting trees. However, there are so many benefits to healthy trees in a landscape that they vastly outweigh the small risk of them falling.
Keep in mind that tornadoes are the most violent natural disasters and may cause complete devastation of homes, neighborhoods, and forests in a matter of seconds. After the Escambia County tornadoes, we witnessed large uprooted trees, downed power lines, flipped vehicles and blown-off roofs. Several homes and apartments were completely flattened or blown off their foundations. Luckily, the odds are in one’s favor of not getting hit directly by a tornado—because there’s often little anyone can do for a landscape in that situation. It’s best to hunker down in a windowless inner room or hallway, which saved the lives of hundreds during the last round of bad weather.
Wind entering the garage of this house may have caused the roof blowout above it. Photo credit: Carrie Stevenson
However, there’s good news that work that can be done to help protect a home during storms. Hardening homes through “windstorm mitigation” techniques can prevent updraft from strong winds. A house is only as strong as its weakest area, and those are typically the connections between the walls, roof, and foundation. A wind-rated garage door and/or brace are crucial, as strong winds can enter a garage and blow out the roof above it.
When strong winds enter a home, their force moving out can cause an updraft and lift off the roof. Graphic courtesy UF IFAS.
In Escambia and Santa Rosa County, the local nonprofit “Rebuild Northwest Florida” operates a cost-sharing program to help residents harden homes. After the tornado in Century (near the Alabama border in north Escambia County), engineers from Rebuild examined a home that suffered a direct hit from a tornado. The home had been retrofit with crucial wind mitigation techniques and sustained no structural damage. Buildings, sheds, and homes all around it were destroyed. Examples of several wind mitigation techniques, including storm shutters, wind-rated windows, garage door braces and a tornado shelter are available for public viewing at the Escambia County Extension office in our windstorm mitigation building.
As the spring storm season heats up and rolls into hurricane season, keep in mind these suggestions for both the landscape and home. As always, contact your local Extension office if you have any questions.
by Beth Bolles | Feb 24, 2016
Magnolias are well known plants to gardeners and many are familiar with the foliage and flowers of these plants. If you are looking for another earlier bloomer, you may want to consider adding a specimen selection to your landscape, the Star magnolia (Magnolia stellata).
Although not native to the United States, star magnolia is a slower growing multi stemmed deciduous shrub reaching about 15 feet in height over time. The best feature are the bright whitish pink star-shaped blooms appearing in late winter before leaves emerge. The flowers offer gardeners a peek of the spring to come and remind us that our Gulf Coast winters are not that long. 
Plants do best in soil with some organic amendments and mulch over the root systems. A planting area that receives a little afternoon shade is ideal but established plants will adapt to sunnier locations when irrigation is provided during drier weather. Only occasional pruning is required to remove crossing branches or those that grow out of bounds. Prune after flowering if needed.
