Do you notice a large number of bees or wasps visiting your magnolia tree? Do you see “bumps on the twigs”? Are the leaves and branches turning black? It is probably Magnolia or Tuliptree scale.
Photo by: Rebecca Bolestra
These scale belongs to a group of insects referred to as soft scales. Scale insects feed by inserting their piercing-sucking mouthpart into the plant’s vascular system and removing sugar and water from the tissue. As the insects feed the fluids become concentrated in the gut of the scale, forcing them to excrete a clear, sticky liquid called honeydew. The honeydew drips onto the leaves, stems and anything else below. Honeydew serves as a growth media for sooty mold, the thin layer of black fungus that forms on the surface. The honeydew is a food source for other insects, like bees and wasps. But, the sooty mold prevents sunlight from reaching the leaf surface, preventing photosynthesis from occurring.
Scales are identified by their body covering. Magnolia scale (Neolecanium cornuparum) is one of the largest soft scale, measuring up to ½ inch in diameter. They range from pink-orange to dark brown in color and are often covered with a white wax at maturity. Tuliptree scale (Toumeyella liriodendri) is a similar appearing scale that can infest magnolia species. But, it does not form the white wax.
Magnolia and Tuliptree scale reaches maturity in August with one generation per year. The female lays her eggs, which hatch internally and form crawlers that move from under the body covering and migrate to the underside of small twigs, where they will spend the winter. Once settled in, the young scales begin to feed and never move again, growing larger in the same spot.
Now is the time to take action. For small trees, the scales can be removed by hand with a soft brush. Horticultural oil will smother adults and crawlers, if the trees to be treated are larger or time is limited. Systemic insecticides can be applied for lasting effects. Imidacloprid is a pesticide that can be applied as a soil-drench, reducing the potential for harm to pollinating insects. In the fall, insecticidal soap can be applied to control the crawlers that hatched. Plan on treating the tree again next year. Scale population suppression usually requires at least two years of pest management. For more information on scale insect management go to: https://edis.ifas.ufl.edu/pdffiles/MG/MG00500.pdf
The dog days of summer are here with high temperatures and humidity. While this sultry weather forces humans to retreat to air conditioning, our gardens suffer because the high night temperatures cause temperate plants to stop flowering, lose vigor and pause growth. By August, many plants in the garden look as bedraggled and wilted as we feel after mowing the grass or trying to weed.
‘Moy Grande’ Hardy Hibiscus (Hibiscus spp.)
All is not lost: the fading flowers and fizzling foliage of traditional garden plants can give way to heat-loving tropicals! Plants that are native to tropical and subtropical climates are naturally adapted to heat, humidity and rain, easily standing up to the worst that our north Florida summers can throw at them. Tropicals offer bright flowers, bold texture and exuberant growth just when the rest of your garden melts in the heat. Tropical plants include trees, shrubs, vines, perennials, groundcovers or annuals, and there are tropicals for full sun, part sun or shade.
Tropical Plants for North Florida
Top tropicals for north Florida gardens are palms, bananas, hibiscus, and gingers. Palms are the iconic symbol of the Tropics. Native subtropical palms can give you the palm vibe without the worry of cold hardiness. These include cabbage palm and related palmettos in the genus Sabal, paurotis palm (Acoelorrhaphe wrightii), saw palmetto (Serenoa repens) and needle palm (Rhapiophyllum hystrix). Non-native European fan (Chamaerops humilis), jelly (Butia spp.), windmill (Trachycarpus spp.), date (Phoenix spp.), Washington (Washingtonia spp.) and other palms also grow well and are cold hardy in north Florida. Most palms grow best in full to part sun but palmettos, saw palmetto and needle palm can handle more shade. Saw palmetto, needle palm and most palmettos grow 3 to 6 ft. tall. European fan, jelly, paurotis and windmill palms grow 10 to 20 ft. tall, while cabbage, Washington and date palms often exceed 40 ft. For best appearance, palms often require special fertilizer (https://edis.ifas.ufl.edu/ep261).
Hardy Yunnan Banana (Musa yunnanensis)
Characterized by their large, bold leaves, bananas are another plant group associated with tropical weather and full sun. Hardier forms of banana that thrive here include Chinese yellow (Musella lasiocarpa), pink (M. velutina), basjoo (Musa basjoo), Yunnan (M. itinerans), and hardy Yunnan (M. yunnanensis). Chinese yellow and pink bananas grow about 5 ft. or more in height, whereas the others have mature heights of 20 ft. or more. Bananas benefit from planting in a location that blocks strong winds so as not to shred the leaves. Depending on the severity of our winter, these bananas may lose some or all leaves but they usually regrow in late spring once warm weather arrives.
The large, colorful and exotic-looking flowers of tropical hibiscus (Hibiscus rosa-sinensis) are associated with the tropics, though this hibiscus is less cold hardy here and is perhaps best enjoyed as a container plant. Other notable hibiscus for north Florida include Confederate rose (H. mutabilis), rose-of-sharon or althea (H. syriacus), and hardy hibiscus (many hybrids of H. moscheutos and other native species). Varying in height from 3 (hardy hibiscus) to 12 ft. (confederate rose), hibiscus thrives in full sun and moist, even wet, soil. Their summer flowers come in colors of white, lavender, pink and red and range in size from a few inches (althea) to the size of dinnerplates (hardy hibiscus)! Except for rose-of-sharon, these hibiscus die back in winter and re-emerge again in late spring.
‘Disney’ Ginger Lily (Hedychium coccineum)
Gingers are also symbolic of the tropics. Many produce complex or colorful flowers and often flowers or other plant parts are aromatic. Ginger lily (Hedychium spp.), spiral ginger (Costus spp.) and shell ginger (Alpinia spp.) have fragrant and colorful racemes or spikes of flowers that appear at the tops of stems 4 ft. to 6 ft. or more tall. Hidden ginger (Curcuma spp.) and true ginger (Zingiber spp.) are lower growing with flowers appearing in “cones” on tops of separate, short stems. Finally, the patterned leaves of peacock ginger (Kaempferia spp.) make a beautiful summer groundcover. Gingers grow best in part sun to part shade.
There are many other tropical plants including coral tree (Erythrina × bidwillii and E. crista-galli), pride-of-barbados (Caesalpinia pulcherrima), fatsia (Fatsia japonica), selloum philodendron (Thaumatophyllum bipinnatifidum), canna lily (the non-invasive Canna × generalis hybrids), peregrina (Jatropha integerrima), elephant ear (non-invasive Alocasia spp. types), Begonia spp. (annual, angelwing and rhizomatous types) and Caladium selections. Bamboos have a tropical look, but many grow aggressively and may be invasive in north Florida. Two recommended clumping bamboos are common bamboo (Bambusa vulgaris; growing 15 ft or more tall) and Chinese garden bamboo (Drepanostachyum falcatum; growing 12 ft. or more tall).
Cockspur Coral Tree (Erythrina crista-galli)
“Tropical” does not necessarily mean “non-native” as there are many Florida natives that provide summer color or texture and are heat loving yet cold hardy in north Florida. These include some palms (cabbage, palmetto, paurotis), ashe magnolia (Magnolia ashei), switchcane (Arundinaria gigantea, a native bamboo), hardy hibiscus (Hibiscus grandiflorus, H. moscheutos and others), golden canna (Canna flaccida), and maypop passionflower (Passiflora incarnata).
Disadvantages of Tropicals
Use of tropicals in your garden does have a downside. Most tropicals are water hogs and need regular irrigation. This isn’t a problem if our area experiences the normal patterns of summer thunderstorms. However, if we don’t receive regular rainfall, tropical plants create the burden of having to water them regularly or else their flowers wilt and leaves droop.
Another disadvantage of tropicals is the “off-season” appearance. Though they thrive in summer heat, they grow slowly during the cooler temperatures of spring and fall and some disappear altogether in winter. Some tropicals are not winter hardy in north Florida and must be replanted each year or undergo elaborate cold protection strategies to help them survive. Other tropicals will over-winter, but often are burned back by frosts, requiring labor to cut back the dead foliage and stems. Finally, tropicals usually require warm weather for growth to resume, and tropicals that die back will produce gaps in your landscape during winter, spring and early summer.
‘Portora’ Giant Elephant Ear (Alocasia sp.)
At the other extreme, some tropicals have such exuberant growth that they are invasive in north Florida. For example, almost all running types of bamboo and many clumping bamboos are invasive, other than those mentioned previously. Also avoid non-native canna (Canna indica), elephant ears (Colocasia and Xanthosoma spp.), Lantana (sterile forms are OK), and some non-native passionvines (Passiflora spp.). If you have questions about a plant’s invasiveness, check the UF/IFAS Assessment of Non-Native Plants in Florida’s Natural Areas, https://assessment.ifas.ufl.edu/.
Using Tropicals in North Florida
Tropicals are best used as accent plants to draw attention in summer when they look their best and the rest of the garden looks its worst. When used as accents, place them throughout the landscape so that winter damage or absences aren’t noticed. Concentrations of tropicals in one area will look great in summer but could look like a mass of dead foliage in winter! To create an entirely tropical-looking planting in north Florida, combine tropical plants with cold-hardy tropical lookalikes (a topic for another time!).
Plant tropicals in late spring once temperatures warm because they will grow slowly or even experience damage at temperatures below 50°F. Best practices for tropicals are to place them in the appropriate exposure for the particular plant (sun, part sun or shade) and keep them mulched. One common characteristic of tropicals is their need for soil moisture, necessitating irrigation to supplement rain. A rich soil or applications of organic mulches or compost can provide nutrients for growth, or light fertilizer applications in summer can boost growth.
Tropicals come alive in the heat of summer. When used in north Florida gardens, tropical plants provide pops of color, luxuriant growth and big, bold, dramatic texture that rescue our gardens from the doldrums of summer!
On a daily basis, it is not unusual for our Extension Office to get calls, emails, and walk-ins with questions about insect identification. Sometimes we even get questions about imaginary insects! The overwhelming opinion by our clientele is that the insects in question are harmful to their landscapes and gardens. This is not always the case since there are more than 100,000 species of insects found in the United States, but less than 1% are harmful.
Recently I received a call about an abundance of bugs in a client’s newly installed sod. He was concerned that the insects were taking over his yard. Luckily, he was able to submit some good quality photos so the University of Florida/IFAS Extension Service could help him identify the insects.
An adult ground beetle (Mochtherus tetraspilotus). Photo Credit: Michael C. Thomas, Florida Department of Agriculture & Consumer Services
The photos were sent to a University of Florida Entomologist for identification verification. It turns out the insects were ground beetles (family Carabidae). Adult ground beetles are slender and range between 1/4″ and 3/8″ in length. Their head and thorax are much narrower than their abdomens. Ground beetles are beneficial insects that feed on moth eggs and larvae. They are known predators of soybean loopers, cabbage loopers, and velvetbean caterpillars. It is suspected that the beetles found by the client came from the sod farm and were living in the thatch layer of the sod. They were possibly feeding on sod webworms or other moth larvae.
Accurate identification is the first step of integrated pest management (IPM). In this case, the insect found wasn’t a pest at all. If you need help identifying an insect, feel free to contact your local Extension Agent. For more information on beneficial insects, visit these publications found at edis.ifas.ufl.edu.
Utility tree trimming truck
With hurricane season upon us, evidence of preparation is all around us. Tree trimmers, contracted by the local electrical utility companies, have been removing trees, branches and other vegetation that is “too close” to power lines. Many homeowners are concerned over the practice.
In order to prevent power outages, the federally approved Vegetation Management Reliability Standard, FAC-033-2, requires utilities to manage vegetation growth along the path of power lines to prevent contact. A minimum clearance of fourteen (14) feet between trees and transmission lines in the right-of-way must be maintained at all times in order to achieve service reliability and public safety.
By Florida Statute 163, an electric utility is granted easement or right-of-way on private property in order to build and maintain electric power lines. Vegetation maintenance allows for the mowing of vegetation within the right-of-way, removal of trees or brush within the right-of-way and selective removal of tree branches that extend within the right-of-way by the electric utility personnel, licensed contractors or International Society of Arboriculture (ISA) Certified Arborists. The choice of how to trim trees and manage vegetation growth near a power line (e.g. pruning, herbicides, or tree removal) is primarily made by the electric utility, subject to state and local requirements and laws, applicable safety codes, and any limitations or obligations specified in right-of-way agreements. An individual may contact the utility company to obtain a copy of the right-of-way agreement for their property.
Over-pruned trees along power line
Sometimes, it appears to some that excessive vegetation has been removed. But, remember the utility companies are required to maintain the appropriate clearance “at all times.” For example, in the summer, power lines sag as they expand from rising air temperatures and heavy use. Also, wind and future growth must be taken into account when determining where to prune. Electric utilities usually prune or remove vegetation to a distance greater than the minimum clearances to account for all these factors. However, in many instances, removal of the tree would be more aesthetically pleasing and could avoid leaving a hazardous tree in the landscape. But, that is not part of their contract. That decision must be made by the property owner.
Tree trimming around power lines may seem like a local issue, but vegetation growth also affects interstate transmission lines. The U.S. Department of Energy estimates that electric utility service interruptions cost businesses and communities tens of billions of dollars annually. Tree contact with transmission lines was the leading cause of the August 2003 blackout that affected 50 million people in the Northeastern United States and Canada. In fact, that particular blackout prompted Congress to pass the Energy Policy Act of 2005, which lead the Federal Energy Regulatory Commission (FERC) to establish the Vegetation Management Reliability Standard.
Should we have a storm that impacts Northwest Florida, remember that the clearing of trees and branches provides faster access for first responders, line repair crews, and other emergency service personnel. So, as you watch the preparation work being done, think about where you will be planting a tree so that it can reach full maturity without threatening power lines, therefore, not requiring “ugly pruning!”
Spacing between trees and power lines
The urban forest is much different from a natural forest. Trees often develop a form that is more susceptible to breakage when grown in developed commercial and residential environments. As a result, trees need preventive pruning to develop strong structure. Research and observation show that well pruned trees can create a more wind resistant urban forest.
Pruning to create stronger tree structure is an ongoing process. To minimize the likelihood of tree damage it is necessary to reduce the length of limbs with a weak attachment to the trunk and to balance the canopy by reducing the length of limbs on the side where weight is concentrated. Do not remove interior branches, as this concentrates foliage at the tips of branches and causes them to break in strong winds.
Limbs that are more than ½ the diameter of the trunk and multiple trunks of similar size must be reduced in order to form strong branch unions and eliminate co-dominant leaders. A reduction cut is pruned back to a smaller lateral branch. Good pruning cuts avoid cutting into the collar. The collar is the swollen area at the base of the branch where it joins the trunk. The tissue is rich in energy reserves and chemicals that hinder the spread of decay.
Preventative pruning only applies to woody tree species. Palms need fronds to protect the bud and provide nutrients for growth. Arborists report that results from previous storms revealed that palms that had been “hurricane pruned” suffered more damage than those that were not pruned. Do not wait until the last minute to prepare your trees for hurricane season. Take action now. For more information on pruning visit: http://hort.ifas.ufl.edu/woody/pruning.shtml.
If you want professional help evaluating your trees or performing the proper corrective actions, visit: https://www.treesaregood.org/findanarborist to locate a Certified Arborist working in your area.
The bay laurel tree in the Escambia County Demonstration Garden had some dead branches on the outer canopy. Further investigation led us to the culprit, the black twig borer. Learn more In the Garden with UF IFAS Extension Escambia County.
The 2020 Atlantic Hurricane Season got off to an early start with some tropical storm activity before the season’s official June 1 start date. We live in a high wind climate. Even our thunderstorms can produce fifty-plus mile per hour winds.
Storm damaged sweetgum tree. Photo credit: Larry Williams
Preventive tree maintenance is key to preparing for storms and high winds.
Falling trees and flying landscape debris during a storm can cause damage. Evaluate your landscape for potential tree hazards. Pruning or removing trees once a hurricane watch has been announced is risky and tree trimming debris left along the street is hazardous.
Now is a good time to remove dead or dying trees, prune decayed or dead branches and stake newly planted trees. Also inspect your trees for signs of disease or insect infestation that may further weaken them.
Professional help sometimes is your best option when dealing with larger jobs. Property damage could be reduced by having a professional arborist evaluate unhealthy, injured or questionable trees to assess risk and treat problems.
Hiring a certified arborist can be a worthwhile investment. To find a certified arborist in your area, contact the International Society of Arboriculture (ISA) at 888-472-8733 or at www.isa-arbor.com. You also may contact the Florida ISA Chapter at 941-342-0153 or at www.floridaisa.org.
Consider removing trees that have low wind resistance, are at the end of their life span or that have the potential to endanger lives or property.
Some tree species with the lowest wind resistance include pecan, tulip poplar, cherry laurel, Bradford pear, southern red oak, laurel oak, water oak, Chinese tallow, Chinese elm, southern red cedar, Leyland cypress, sand pine and spruce pine.
Broken pine from hurricane. Photo credit: Larry Williams
Pine species vary in their wind resistance, usually with longleaf and slash pines showing better survival rates than loblolly and sand pine. However, when pines become large, they may cause a lot of damage if located close to homes or other valuable structures. As a result, large pines are classified as having medium to poor wind-resistance. For this reason, it’s best to plant pines away from structures in more open areas.
Before and after a storm, tree removal requires considerable skill. A felled tree can cause damage to the home and/or property. Before having any tree work done, always make sure you are dealing with a tree service that is licensed, insured and experienced.
More information on tree storm damage prevention and treatment is available online at http://hort.ifas.ufl.edu/woody/stormy.shtml or from the UF/IFAS Extension Office in your County.