This article was written by: Joanna Jaramillo Silva1, Rachel Mallinger2, Xavier Martini3
1 Ph.D. Student, University of Florida, Department of Entomology and Nematology
2 Assistant Professor, University of Florida, Department of Entomology and Nematology
3 Assistant Professor, North Florida Research and Education Center, University of Florida, Department of Entomology and Nematology
Bees are the primary pollinators of plants, essential in natural and crop environments for guaranteeing global food security to the human population. Florida is home of more than 300 species of native wild bees, which rely on pollen and nectar from flowers to survive. However, a global pollinator decline reported for honeybees and wild species (including insects, birds, and bats), is decreasing the worldwide provision of pollination services. Food limitation (pollen and nectar), resulting from decreasing flower diversity and quantity, is one of the multiple causes of pollinator decline. Pollinator-friendly plants are receiving attention from people of various disciplines such as the scientific community, stakeholders, Master Gardeners, and citizen science groups willing to participate in pollinator conservation efforts.
Domestic gardens
Domestic gardens comprise a substantial proportion of land in the urban landscape and are often the most significant component of green space; they play essential roles in conserving plant genetic resources, insects, and other wildlife, and have social and economic value. Gardens behave as islands of usable habitat surrounded by urbanization, and they present varying benefits for pollinators. There is generally a positive relationship between high pollinator abundance, flower diversity, and bloom evenness. Gardens for pollinators propose to solve the pollinator crisis by enlarging greenspaces in urban areas by planting more flowers in urbanized environment and by improving the diversity of floral resources for pollinators.
Pollinator friendly plants
There are different categories of floral traits: qualities that attract pollinators such as floral size and color, and physical characteristics that reward the pollinator (nectar and pollen quantity and quality). Flowers with higher quality and quantity rewards are more attractive to pollinators. Nectar provides the main sugar source for insect pollinators; its energetic value is determined by its sugar concentration. The volume of nectar produced by flowers will directly affected visitation by honeybees and bumblebees, butterflies, and birds. Pollen on the other side, consists of the main source of protein for most pollinators.
RECOMMENDATIONS
1. Provide a Mix of floral shapes and sizes.
There is usually a positive correlation between flower size and nectar volume: long tube flowers usually provide more nectar, whereas open or flat flowers provide more pollen. In addition, flower shapes are also associated with different pollinator types (Fig. 1). Long-tongued insects (Butterflies, and some bees) visit deep corolla tube flowers, while short-tongued pollinators (wasps, flies and some bees) remain on short tube or open corolla flowers.
Figure 1. Examples of plants with long tube flowers, short-medium, and open corolla flowers (From left to right: Butterfly on a Pardon my pink (Monarda didyma) (Credits: Joanna J. Silva); Carpenterbee on Salvia Indigo spires (Salvia longispicata x farinaceae) (Credits: Kelly Thomas); Sweat bee on Gaillardia pulchella) (Credits: Joanna J. Silva).
2. Provide a mix of flower colors
Color patterns influence the flower’s attractiveness and increase the efficiency of pollination by helping insects orient on the flower and guide them to the reward (Fig. 2). Bees prefer white, yellow, or blue-purple flowers. Orange, pink, and red flowers attract other pollinators such as butterflies.
Figure 2. Examples of native plants to Florida that display different colors Native to Florida (From left to right: Butterfly on Spanish needles (Bidens alba), Tickseed coreopsis (Coreopsis leavenworthii), Sckullcap (Scutellaria arrenicola), Pitcher sage (Salvia azurea), Swamp Rose-mallow (Hibiscus grandiflorus), Carpenterbee on False-Rosemary (Conradina grandiflora), Spotted beebalm (Monarda puctata), Blanket flower or Firewheel* (Gaillardia pulchella) . Credits: Joanna J. Silva *A recent discovery suggests that Firewheel is not considered native to Florida, but it is widely cultivated. It is probably not native to the rest of the eastern USA as previously thought (ISB: Atlas of Florida Plants (usf.edu), Gaillardia – University of Florida, Institute of Food and Agricultural Sciences (ufl.edu)).
3. Include a pollinator hotel
Add a bee nest box for the native bees that build their nests above ground. Solitary bees and wasps will take up residence in a pollinator hotel after you place it outside.
4. Provide flowers throughout the year.
Pollen and nectar collection varies seasonally for honeybees, while many other solitary bee species collect pollen continuously during adult foraging to feed their larvae. Design the garden to have three or more different plants blooming at any given time during the growing season, which is March through November in northern areas of the state (Fig. 3).
Figure 3. Honeybee on Viburnum (Winter) (Credits: Joanna J. Silva), Honeybee on Salvia Indigo spires taking nectar (Spring-Summer) (Credits: Walker Bensch), False Rosemary and Muhlly grass (Muhlenbergia capillaris) (Fall) (Credits: Joanna J. Silva).
5. Include native plants.
A “Florida native plant” refers to a species occurring within the state boundaries prior to European contact, according to the best available scientific and historical documentation. Florida is home to over 4,867 species of plants; 3,314 species are considered native of which 230 species are endemic.
6. Chose the right plant for each location.
Success depends on using the right plant in the right place, especially by considering plant’s cold hardiness (Fig. 4). Plant selection for landscapers, nurseries, and gardens requires individual site criteria and an evaluation of individual plant performance under different environmental circumstances, such as water, soil, and temperature.
Figure 4. Hardiness zones in Florida (http://planthardiness.ars.usda.gov).
Being a gardener in Florida is exciting. We have many plants to choose from and the weather is mostly pleasant but always seeming to surprise us. One disadvantage of living in such a place, in addition to having so many growing zones, landscape nurseries, and major shipping ports, is that invasive species that land in Florida don’t like to leave. One newcomer in the lineup of invasive pests is the crape myrtle bark scale (Acanthococcuslagerstroemiae). This invasive insect pest made its way from Texas and, as of a few weeks ago, the only Florida sighting had been in Santa Rosa County. Unfortunately, this pest has now been confirmed in Leon County. Landscapers and gardeners in north Florida should learn how to identify this pest and what options are available for control.
The crape myrtle bark scale, as the name suggests, has a pretty specific host – the crape myrtle (Lagerstroemia spp.). However, in the United States, this scale has also been found feeding on our native beautyberry (Callicarpa americana). Due to the widespread planting of crape myrtles, these should be the gardeners primary focus when looking for this new pest. If present on the tree, it is hard to miss. These scales feed on the bark and are a snow-white color. Being a scale, they produce honeydew that is then covered in black sooty mold. So, if you see a crape myrtle with black branches, look closely and you may see the white scales. If you crush these scales and they leave a pink goo on your fingers, then you very likely have crape myrtle bark scale. Of course, you can send a picture or sample to your local county extension office for confirmation.
Black sooty mold and white scales along the trunk and branches are a tell-tale sign of crape myrtle bark scale. Credit: Mark Tancig, UF/IFAS.
If you do happen to find crape myrtle bark scale in your own landscape, or one that you manage, proper control is important to prevent it from moving along any further. Since scales suck on sap and are protected by an outer shell, systemic insecticides are the preferred product for effective control. These include the neonicotinoids, such as imidacloprid (Merit) and dinotefuran (Safari). The larval stage can be controlled with a horticultural oil, sometimes mixed with another insecticide like bifenthrin (Talstar), however, this will not control the adults. Another option is to completely remove the tree and burn all of the plant material.
Excessive sooty mold has turned these branches black. Be on the lookout for crape myrtles looking like this to help identify crape myrtle bark scale. Credit: Jim Robbins, Univ. of Ark. CES. Retrieved from bugwood.
The crape myrtle bark scale can significantly reduce the aesthetic value of crape myrtles due to the black sooty mold that covers the bark. It is also known to reduce flowering and can lead to thinning of leaves. Since crape myrtles make up a big part of our managed landscapes, let’s all work together to scout for this pest and control it when found. If you have questions, please contact your local county extension office.
Difference in flowering due to crape myrtle bark scale damage. Credit: Jim Robbins, Univ. of Ark. CES. Retrieved from bugwood.
The weather is the most important factor determining where certain fruits can be successfully grown. Terms such as chilling requirement and cold hardiness play a major role in both species and variety selection.
Most fruits which grow in the Panhandle are deciduous, meaning that during the winter, they lose their leaves and go through a semi to full dormancy period. This period is a much needed rest and reset for the plant. The cool season actually helps the plant to rebound for another fruiting season and affects how well the plant will yield fruit. This is where the term “chilling hours” comes into play.
Temperatures below 45 degrees Fahrenheit are considered “chilling”. The number of hours below 45 degrees accumulated throughout the winter determines the total amount of chilling hours. Different species of citrus and dooryard fruit, along with different cultivars of these plants differ in the amount of chilling hours need for that all important rest & reset period. Satsuma is a popular fruit trees in our area, as it is by far the most cold hardy citrus. Evidence suggests that the satsuma can survive a temperature as low as 14 degrees Fahrenheit.
Figure 1. Mature satsumas ready for harvest.
Credit. Pete Anderson. UF/IFAS Extension.
What happens if the plant doesn’t receive the needed amount of chilling hours? Plant hormones can be disrupted, and both leafing and blooming could be light and come outside of the normal range of the season. So, where do we stand in the Panhandle for overall chilling hours? Typically, we see approximately 500 hours chilling hours. Therefore, its best to plant citrus and dooryard fruit that have the characteristic of needing 500 or less hours for chilling. Please see this informative document on citrus and dooryard fruit varieties: https://edis.ifas.ufl.edu/publication/MG248
Now, on to the term cold hardiness. By definition, this is the plants ability to withstand cool season temperatures without injury. Most tropical fruits cannot tolerate our Panhandle temperatures. Those of us that cut back banana trees every year know this all too well. To check your plant hardiness zone, please see the USDA Plant Hardiness Zone Map: https://planthardiness.ars.usda.gov/
Before you plant a fruit tree, make sure you understand about its cold hardiness and whether or not it has a chilling requirement. This will both save you money and a headache, in the end. If you’re in doubt about a particular variety, contact your local extension office.
Any North Florida resident who has tried their hand at growing apples, peaches, or plums may occasionally find themselves frustrated by a year (or two…or three) with a poor or nonexistent harvest. What has gone wrong? Are the trees getting a disease? Were they not fertilized properly?
It may be that the tree owner has done everything correctly, but the weather is actually to blame. The answer to “what has gone wrong?” may lie with a concept called “chill hours”. Plants that are adapted to living in colder climates need some way to figure out when the winter is over. If a plant starts blooming too early, it’s likely that a frost will come along and knock out this year’s flowers. No flowers, no fruit. For a plant, this means no little baby plants this year to keep the species going. To avoid this, some plants have figured out a way to detect and keep track of how cold it’s been in a particular year. When enough hours of cold weather have accumulated, that’s usually a safe signal that spring must be near. This means it’s time to blossom when the weather next warms up.
Usually. Different varieties of plants are adapted to blossom at different times of year, depending on the average amount of cold weather the area they live in gets each year. A plant from a colder climate might not start growing flowers until it has detected 1,000 hours of cold…or more! Given that the temperature range that counts as a chill hour is around 32-45 degrees Fahrenheit, you might correctly guess that such varieties will NOT do well in Florida. In north Florida, we receive somewhere from 500-700 chill hours each year. This winter (as of February, 2023), we have received 479 chill hours in Walton County.
Chill hour total for Walton County, as of Feb 1, 2023
That’s not a lot, and we may not get much more weather that plants recognize as cold enough to count. Apple growers with varieties that need even as few as 500 chill hours may not be making many pies this year. So what can be done?
First, temper your expectations. Understand that even though we may get the occasional hard freeze, it may not count any more toward the chill hour requirement than temperatures just above freezing. Then, when it warms up the following week, those 70 degree temperatures may actually set BACK the chill hour clock for some plants.
Second, choose varieties that require few chill hours in the first place. A ‘Honeycrisp’ apple, needing 800-1000 chill hours each year, is probably never going to produce fruit in the panhandle of Florida. Other apple varieties might, though! Try varieties such as ‘Anna’ (which needs only 300 chill hours), ‘Dorsett Golden’ (250 hours), or ‘Tropic Sweet’ (300 hours). For peaches, try varieties like ‘GulfAtlas’, ‘Gulfcrimson’, or ‘Gulfsnow’ (400 hours each).
Third, consider learning to love other types of fresh fruit. Persimmons, figs, kumquats, and loquats may not show up very often in treasured family recipes, but they can offer a tasty alternative to plants that simply might not be well adapted to our climate.
Peaches are popular, but they may not produce fruit every year!
For more information, try these links:
To calculate how many chill hours your specific area has received, check out the tool at agroclimate.org.
Pecans are a flavorful and nutritious nut and an essential component of a southerner’s diet. The trees also provide nice shade and intense fall color to landscapes throughout the south. However, not all pecan tree varieties are suited for the Florida panhandle. There are a number of things you should consider before planting a pecan tree.
Pecan tree grove in North Florida. UF/IFAS Photo: Thomas Wright.
Site Selection – Pecan trees are native to the river valleys of North America. They perform best in deep, fertile, well-drained soils. The key is that the soil is well-drained. Pecan trees will not do well in soils that hold a lot of water and do not drain quickly. Pecan trees also need space to grow. Trees should be planted at least sixty feet apart and at least sixty feet from other large trees and structures. This will allow adequate light for the trees produce a good crop.
Disease Resistance – Pecan scab is the most detrimental pecan disease in the southeast. Trees advertised as scab resistant in the past may have become more susceptible over time. A few varieties that seem to be available at tree farms and have maintained their scab resistance are ‘Caddo’, ‘Elliot’, ‘Lakota’, and ‘Gafford’. Newer varieties that currently have good scab resistance are ‘Avalon’, ‘Huffman’, and ‘Whiddon’. However, these newer varieties may be more difficult to find at nurseries and farm stores.
Pollination – Pecan trees produce both female and male flowers on the same tree. Trees are split into two pollination groups. Type I pollinators produce mature pollen before their female flowers are receptive and Type II trees produce receptive female flowers before their pollen is mature. Timing of flower maturity may change with tree age, but it is a good practice to plant a Type I tree along with a Type II tree to ensure a good crop in each tree. A pollination compatibility chart can be found at UGA Pecan Compatibility Chart.
Planting – Commercially, pecan trees are most commonly planted as bare-root transplants, but container-grown trees can also be used. Bare-root trees are usually cheaper and more readily available. They should be planted while dormant, between December and March and should be planted the day they are delivered. If the root system looks dry, soak the trees in water for a few hours before planting. Container-grown trees can be planted any time of the year, but they have the best chance of survival if planted during dormancy. Trees should be planted at the depth they stood at the nursery or the depth they were planted in a container. Planting holes should be at least 18 inches wide and only native soil should be used to fill in the hole. The main causes of death in young trees are planting too deep and inadequate moisture during the first two years following planting.
Pecan trees provide focal points in the landscape and a tasty treat for the belly. For more information on growing pecans and the benefits of pecans please see these Pecan Publications from the University of Georgia.
