by Larry Williams | Aug 14, 2020
Oleander caterpillars, which are active on some oleanders during summer, can provide a number of gardening lessons.
Oleander caterpillar moth on lantana flower. Photo credit: James Castner, UF
The adult moth is striking in appearance. The bluish to purplish moth has white dots on its black wings. The moths resemble wasps as they fly in and around oleander shrubs.
It’s the orange caterpillars with black spots and black hairs that cause problems for some gardeners.
Caterpillars are the larval stage of butterflies and moths. In order to enjoy watching butterflies and moths feeding on the nectar of flowers, some of the caterpillars must survive to become adult butterflies and moths. This is lesson number one.
Oleander caterpillars usually only feed on oleander plants. Oleanders are native to areas of Europe and Asia. This is lesson number two.
Oleander caterpillar, Photo credit: Paul Choate, UF
Oleander caterpillars benefit by us planting their food source in Florida.
This relationship between pest and plant is referred to as the key plant, key pest concept. Some other examples include St. Augustinegrass and chinch bugs, gardenias and whiteflies, crape myrtles and crape myrtle aphids, azaleas and azalea caterpillars, camellias and tea scale, roses and black spot, pecans and pecan scab, squash and squash vine borers.
Understanding this concept can be helpful in designing a “low maintenance” landscape.
When you plant roses, you plant everything that goes with roses, including the time and money required to maintain them. This applies to St. Augustinegrass, pecan trees, squash and oleanders. This is lesson number three.
Oleander caterpillars can temporarily damage the appearance of oleanders. But they cause no long-term damage for the plant. This is lesson number four. The damage is aesthetic. Oleander caterpillars can consume great numbers of leaves. However, if the plant is otherwise healthy, new leaves will be produced and the plant will continue to grow. The damage is temporary; there will be no evidence the plant ever had a problem.
To spray or not to spray for oleander caterpillars has to do with a person’s tolerance level.
If you can’t tolerate having oleander caterpillars around and the temporary aesthetic damage they cause, consider the use of Bacillus thuringiensis. It is sold under a number of brand names and many times is referred to as Bt. This bacterium only controls caterpillars so it is friendlier for the beneficial insects. When using any pesticide, always follow the label directions and precautions.
Here are links to UF/IFAS Extension publications with more info.
by Carrie Stevenson | Aug 14, 2020
Austin N. Fife, PhD student, Entomology
University of Florida IFAS
North Florida Research and Extension Center
Phyllocoptes fructiphilus: a new threat for Florida roses
Figure 1: Phyllocoptes fructiphilus . Image Credit Austin N. Fife, UF / IFAS
Phyllocoptes fructiphilus Kefier is a microscopic plant-feeding arachnid belonging to a group of spindle-shaped mites known as Eriophyoid mites. Eriophyoid mites are second only to spider mites in their economic importance and potential for plant damage: some species create galls, others deform plants with their feeding activity, and a few species are capable of spreading viruses. Fortunately, eriophyoid mites very host specific and P. fructiphilus only feeds on plants in the genus Rosa, which includes all of the true roses which we are familiar with.
P. fructiphilus does not cause damage by its feeding alone, but is a pest due to its relationship as the vector of an emaravirus: Rose rosette virus (RRV). RRV infection creates Rose Rosette Disease (RRD), with the following symptoms: witches’ brooms/rosetting, deformed flowers, increased prickle density, elongated shoots, reddened leaves and stems, and increased die-back which ultimately kills the rose host. RRD is the most serious disease of roses, creating millions of dollars of losses for growers. Rose Rosette Disease and the mite have invaded the southeastern United States as the non-native Rosa multiflora (Thunb) has spread invasively towards the eastern coast and by the introduction of infected roses from out of state into Florida.
Figure 2: EDDMapS. 2020. Early Detection & Distribution Mapping System. The University of Georgia – Center for Invasive Species and Ecosystem Health. Available online at http://www.eddmaps.org/
RRD was initially detected in Florida in 2014 on 15 plants; however, the plants were destroyed and P. fructiphilus were not detected on the roses after that time.
In early 2019, a survey of predatory mites on roses found eriphyoid mites in samples obtained while surveying roses in Leon County, Florida. The mites were sent to the Florida Department of Agriculture and Consumer Services – Department of Plant Industry (FDACS-DPI) and were all identified as P. fructiphilus by Dr. Sam Bolton. To date, none of these roses have shown signs or symptoms of RDD and none of these plants have tested positive for presence of the virus.
Figure 3: Black dots indicate individual sites which have been surveyed for Phyllocoptes fructiphilus. Orange dots indicate a number of sites with populations of P. fructiphilus detected in Leon county, Florida. No symptoms of Rose Rosette Disease have been seen on these plants to date. Image Credit Austin N. Fife, UF / IFAS
This is the first recorded instance of P. fructiphilus in Florida and is worrisome despite the absence of the virus. Fortunately, RRV is currently not established in Florida. However, the presence of P. fructiphilus, along with past detections of RRV in Florida warrants an increase in monitoring efforts for the mite and virus in Florida.
Figure 4: Typical symptoms of Rose Rosette Disease. Image Credit Austin N. Fife, UF / IFAS
How can I identify roses that have Rose Rosette Disease?
It is difficult to identify the symptoms of RRD in the field for a few reasons. Primarily, there are different growth habits for different rose cultivars. What appears to be ‘excessive thorniness’ in one cultivar may be normal for another, and is can be easy to mistake the redness of new flush with symptoms of the RRD. In addition, glyphosate damage from improper use of Roundup or similar products can have a very similar appearance to diseased roses. The best way to verify RRD infection is to use molecular testing for the virus. Identifying the presences of eriophyoid mites is useful for diagnosis, but they are too small to see with pocket loupes and are difficult to find unless there are large numbers of mites. To properly identify an eriophyoid mite as P. fructiphilus requires the use of a compound microscope with a specially prepared microscope slide of the mite, as well as reference materials and a trained individual who knows what characters to look for.
What to do if I suspect that my roses are infected with Rose Rosette Disease?
We recommend reporting suspected cases of RRD to your local extension agency or the Florida Department of Agriculture.
Where should I send my samples?
Plant Disease Diagnostic Clinic at the North Florida Research and Education Center in Quincy: https://nfrec.ifas.ufl.edu/plant-pathology-clinic/
Mathews Paret, Director, Plant Disease Diagnostic Clinic – UF NFREC (850) 875-7154, paret@ufl.edu
UF/IFAS Disease Diagnostic Center in Gainesville:
- 392-1795, pdc@ifas.ufl.edu
2570 Hull Rd Gainesville, FL 32603
Florida Department of Agriculture and Consumer Services – Division of Plant Industry
1-888-397-1517 Helpline (352) 395-4600 (Helpline Number, Outside of the United States) DPIHelpline@FDACS.gov
The Doyle Conner Building 1911 SW 34th St. Gainesville, FL 32608
Figure 5: Phyllocoptes fructiphilus is a refuge-seeking mite ,which hides under rose sepals, which are covered in tiny glandular plant hairs known as trichomes that protect the mites. Image Credit: Austin N. Fife, UF / IFAS
How Can I Manage Rose Rosette Disease?
Currently, there are no commercially available rose cultivars known to resist Rose Rosette Disease or Phyllocoptes fructiphilus. A major difficulty lies in the cryptic nature of these mites, which hide underneath the rose sepals. It is important to consider this when considering which control methods to use. Methods which require direct contact with the mites to kill them are unlikely to work.
This makes it difficult for chemical applications which require contact with the pest to work.
Keeping that in mind, there are a few things you can do to reduce your risk of RRD and prevent the spread of the mite:
- Eliminate infected wild roses nearby
- Heavy pruning followed by horticultural oil spray may reduce populations of the mite, but cannot prevent a viral infection from spreading.
- Space plants so their leaves and roots don’t touch
- Dispose of diseased roses properly: bag up infected materials and dispose of in areas away from other roses
- After removing infected plants, spray remaining plants with miticides recommended at https://roserosette.org/control/
- Spray uninfected plants adjacent to removed (infected) plants
by Daniel J. Leonard | Jul 23, 2020
Flowers can often be fickle in the landscape, so, this year, I decided to add a shot of no-maintenance color to my landscape with foliage plants! The benefits of ornamentals that don’t need flowers to put on a show are many. Their water and fertility needs are often less because they don’t have to support the large energy and irrigation requirements the flowering process demands. They don’t need deadheading to look their best and they lend an awesome texture that is overlooked in many landscapes. My summertime foliage plant of choice provides all those things in a small, bright yellow package; it’s a widely sold selection of Duranta called ‘Gold Mound’.
Mass of ‘Gold Mound’ Duranta in the author’s landscape.
‘Gold Mound’ Duranta is a small shrub known for its chartreuse to bright yellow foliage and generally grows 24” or so tall and wide in the Panhandle, allowing it to fit in nearly any landscape. ‘Gold Mound’ has been around in the horticulture trade a long time and is a popular perennial shrub in the southern parts of Florida. It was recognized as the Florida Nursery, Growers, and Landscape Association’s (FNGLA) plant of the year in 2005 and regularly occupies a spot in the color displays of big box and local nurseries, even in the Panhandle, however, despite these attributes, ‘Gold Mound’ is a rare find in Northwest Florida landscapes. That needs to change!
In our neck of the woods, Duranta ‘Gold Mound’ is incredibly low maintenance. I planted a grouping of thirteen specimens near the end of my driveway to provide a consistent season long splash of color to complement the fleeting blooms of the spring flowering shrubs, the drab greenery of the neighbor’s lawn and the on-again, off-again ‘Drift’ Roses they share the bed with. The result has been awesome! I watered frequently until the small shrubs were established and on their own, with no irrigation since. I fertilized at planting with a slow release, polymer coated fertilizer and have not had to help them along with subsequent applications. Even better, despite our frequent rainfall and heat/humidity, no pests or diseases have come knocking. Just because I enjoy gardening doesn’t mean I need a landscape full of divas and I can count on ‘Gold Mound’ to not need pampering.
Incredible chartreuse foliage of ‘Gold Mound’.
Maybe my favorite part of ‘Gold Mound’ Duranta in the Panhandle is that it isn’t permanent. Duranta is a native of the Caribbean tropics and is not particularly cold hardy, most Northwest Florida winters knock it back hard, if not outright killing it. Therefore, ‘Gold Mound’ is best enjoyed here as an annual, planted when the weather warms in the spring, enjoyed until the first frost, then pulled up and discarded. Easy peasy. No long-term commitments required. My uncle, the chainsaw gardener, doesn’t even have to chop it back! Just compost the plants each winter or toss them in the trash, hit up your local nursery the next spring for some new plants and do it all over again. Though it has to be replanted each year, Duranta ‘Gold Mound’ won’t break the bank. The generic ‘Gold Mound’ is commonly sold in 4” containers for just a few dollars apiece in the annual section of plant nurseries, making it a very affordable option, especially compared to some of the new, designer perennials it competes with.
Though some landscape designers recommend just using a single specimen of ‘Gold Mound’ here and there for small pops of color, I prefer using groupings of the plant. I’ve seen successful plantings of ‘Gold Mound’ massed in large groups to create annual color beds at key points in landscapes and also planted across the front of a bed to complement darker foliaged backdrop or foundation plants, such as Boxwood or Loropetalum. Regardless of how you decide to use them in your yard, I don’t think you can go wrong with adding some color pizazz to your landscape with the inexpensive, low-maintenance, Florida-Friendly plant, ‘Gold Mound’ Duranta. Happy gardening!
by Julie McConnell | Jul 16, 2020
We hope you were able to join us for Gardening in the Panhandle LIVE! Butterfly Gardening on July 9th to learn about attracting butterflies to your Florida gardens. As promised, we have compiled a list of butterfly resources that we talked about during the webinar and a few extra that we didn’t have time to cover.
If you were not able to join us live, you can still watch the videos on Facebook or YouTube
Click on the topic of interest for links to resources:
Don’t forget to tune in for our next Gardening in the Panhandle LIVE! on July 23rd for Prepping for the Fall Garden. Register for that webinar on Zoom or Follow our Facebook Event for updates.
For a full list of upcoming webinars visit Gardening in the Panhandle: LIVE!
by Matt Lollar | Jun 23, 2020
I live in the woods, so I mainly have a “natural” landscape. I remove trees, shrubs, and weeds as I see fit, but for the most part things just grow wild. However, there are a few spots in the yard where the previous owners did a little landscaping. Unfortunately, these spots have become a bit overgrown. One spot in particular features some gardenia plants around the HVAC units. At first, I was a little hesitant to prune these shrubs because they provide some shade to the units. However, they have become overgrown and I know they will grow back. I was patient to wait for them to finish flowering.
A gardenia shrub that has become a bit overgrown. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
As you can see in the photo above, this gardenia has become a bit leggy. It is important to also note the good amount of branching and new growth at the base of the plant. There are a few pruning options available for shaping shrubs such as hedging/terminal pruning, selective pruning, and renewal pruning. While a tree form gardenia can be attractive, it wasn’t desired in this situation. This particular case called for renewal pruning to improve the form of the plant. Renewal pruning is probably the easiest type of pruning, because it requires the least amount of thinking. It basically involves removing the majority of old growth.
A gardenia shrub that has been renewal pruned. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
The picture above is of the same shrub that has been pruned heavily. Not only have the older, leggy branches been removed, but some of the newer growth has been removed to allow for better air circulation within the shrub. This will help reduce the incidence of disease.
A gardenia shrub six weeks after renewal pruning. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
Six weeks after being pruned, this shrub is flowering for a second time. In a matter of short time it will be providing much needed shade for the HVAC units again. (That is..if I remember to selectively prune throughout the year.) For more information on how to prune and what to prune, please visit the UF/IFAS Gardening Solutions page on pruning.
by Daniel J. Leonard | Jun 2, 2020
Pineapple Guava (Acca sellowiana) hedge. Photo courtesy of the author.
One of the most common questions I’ve gotten across the Panhandle over the last several years is “What can I plant to screen my house and property?” I surmise this has a lot to do with Hurricane Michael wiping properties clean and an explosion of new construction, but whatever the reason, people want privacy, they want it quickly, and they often want something a little more natural looking and aesthetically pleasing than a fence. Like everything else, the answer to the question is nuanced depending on the site situation. However, if the situation is right, I almost always recommend that clientele at least consider a woefully underutilized plant in the Panhandle, Pineapple Guava (Acca sellowiana).
Named a Florida Garden Select Plant by the Florida Nursery Growers and Landscape Association (FNGLA) in 2009, Pineapple Guava is a standout screening and specimen plant, passing all the usual tests homeowners demand from shrubs. Growing 15’x15’ or so if never pruned or sheared, these quick-growing evergreen shrubs sport pretty, leathery green leaves with gray to white undersides. This leaf underside coloring causes the plants to emit a striking silvery blue hue from a distance, a very unusual feature in the screening shrub world.
Pineapple Guava (Acca sellowiana) silvery blue leaf undersides. Photo courtesy of the author.
Look past the leaves and you’ll notice that Pineapple Guava also possesses attractive brownish, orange bark when young that fades to a pretty, peely gray with age. To complete the aesthetic trifecta, in late spring/early summer (generally May in the Panhandle), the plants, if not heavily sheared, develop gorgeous edible, pollinator-friendly flowers. These flowers, comprised of white petals with bright red to burgundy stamens in the center, then develop over the summer into tasty fruit that may be harvested in the fall.
In addition to being a superbly attractive species, Pineapple Guava is extremely easy to grow. They like full, all-day, blazing sunshine but will tolerate some shading if they receive at least six hours of direct sun. Well-drained soil is also a must. Pineapple Guava, like many of us, is not a fan of wet feet! Site them where excessive water from rain will drain relatively quickly. Adding to its merits, the species is not plagued by any serious pests or diseases and is also drought-tolerant, needing no supplemental irrigation once plants are established. A once a year application of a general-purpose fertilizer, if indicated by a soil test, may be useful in getting plants going in their first couple of years following planting, but is rarely necessary in subsequent years. To maintain Pineapple Guava as a formal hedge or screen, a simple shear or two each growing season is normally enough. The species also makes an outstanding small specimen tree when allowed to grow to its mature height and “limbed-up” to expose the interesting bark and limb structure.
Edible, pollinator-friendly Pineapple Guava flowers in bloom. Photo credit: Larry Williams
If you’ve been looking for a quick-growing, low-maintenance screen or a specimen plant for a large landscape bed, you could do a lot worse than the Florida-Friendly Pineapple Guava! As always, if you have any questions about Pineapple Guava or any other horticulture, agriculture or natural resource related issue, contact your local UF/IFAS County Extension Office!
