Not all fall color is a good thing. This statement is especially true when it comes to twig pruners and twig girdlers. These two species of longhorned beetles can certainly disappoint your grand expectations of a beautiful array of fall color. Both species cause the tips of twigs to fall to the ground in late summer, sometimes leaving your trees in an undesirable form.
Twig Pruners
The twig pruner (Elaphidionoides villosus or Anelaphus villosus) is a small longhorned beetle that attacks numerous species of hardwoods. It is usually classified as a secondary pest of declining trees and shrubs. Female twig pruners lay their eggs in late spring at the leaf axils. When the eggs hatch, the grubs bore into twigs and continue to bore as they mature. The larvae then chew concentric rings just underneath the bark. The infested twigs and branches eventually drop to the ground with the larvae inside. The larvae pupate inside the fallen twig throughout the winter.
An adult twig pruner. Photo Credit: University of Georgia
Twig Girdlers
The twig girdler (Oncideres cingulata) is a small longhorned beetle that invades many species of hardwoods. Female twig girdlers lay their eggs in late summer in small twigs (about 3/8 inch diameter) that are covered with a thin layer of bark. The female chews a concentric ring around the outside of the twig, causing the end of the twig to die. The female chews a small notch in the dead twig and lays her eggs. After the eggs hatch, the larvae feed on the dead twigs and develop into adults before chewing their way out. The adults fly away to new host trees.
An adult twig girdler. Photo Credit: Lacy L. Hyche, Auburn University
Management and Control
It’s important to plant the right plant in the right place. Healthy trees and shrubs are the best defense against insect pests. Twig pruners and twig girdlers live in dying or dead twigs and branches. If you have trees that have suffered damage from these pests you will notice an abundance of fallen twig ends around the base of your trees. Rake and remove fallen twigs from around the trees and destroy or dispose them. This will help reduce pruner and girdler numbers in subsequent years.
Sometimes we just need a little privacy. This is especially true if you live on a busy road or just have annoying neighbors. There are a few things to consider when selecting a screen tree: 1) full-grown size; 2) speed of growth; and 3) aesthetics. With these three factors in consideration, let’s review some screen options for different situations.
Pineapple Guava (Acca sellowiana) hedge. Photo Credit: Daniel Leonard, University of Florida/IFAS Extension – Calhoun County
Pineapple Guava (Acca sellowiana)
At one time this shrub was hard to find, but it is slowly becoming more available. Pineapple guava is native to South America, but it adapts well to the Florida Panhandle. This plant can reach 10 to 15 feet in height with an equal spread and has a moderate rate of growth, so it’s a great choice when you just need a small screen. Pineapple guava is moderately salt-tolerant and does well in coastal landscapes. As a bonus, the flowers and fruit are edible. It’s hard to find a more aesthetically pleasing large shrub. Pineapple guava is evergreen with leathery green leaves that have grey undersides. This plant can be grown as a large shrub or pruned to be a small tree.
A large ‘Emily Bruner’ holly at the Santa Rosa County Extension Office. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
‘Emily Bruner’ Holly (Ilex x ‘Emily Bruner’)
‘Emily Bruner’ holly is a cross between the Chinese holly (Ilex cornuta) and the lusterleaf holly (Ilex latifolia). This evergreen shrub has glossy green leaves. It has a pyramidal growth habit and is listed as reaching 15 to 20 feet tall by 5 to 8 feet wide, however the specimen at the Santa Rosa County Extension Office is about twice that size. ‘Emily Bruner’ holly prefers moist, well-drained soil. This holly has dense, prickly leaves so it does well keeping people out of your yard in addition to buffering sound. The flowers have a sweet scent and are a favorite of honey bees.
Dahoon holly foliage and berries. Photo Credit: University of Florida/IFAS
Dahoon Holly (Ilex cassine)
Dahoon holly is native to North America, is tolerant of wet, shady sites (but can also handle full sun), and displays some salt tolerance. This evergreen, small tree is somewhat shrubby. It can grow to be 25 to 30 feet in height with an 8 to 12 foot spread. Dahoon holly has nice light green leaves that are smooth, not prickly like ‘Emily Bruner’ holly. It has a moderate growth rate.
Bracken’s Brown Beauty as an accent tree in a lawn area. Photo Credit: Beth Bolles, University of Florida/IFAS Extension – Escambia County
Southern Magnolia (Magnolia grandiflora)
It’s hard to beat a majestic southern magnolia in the landscape. Why not utilize it as a screen tree? Now, not all southern magnolias are made equal. There are a few cultivars that do well as screens as well as on their own. ‘Bracken’s Brown Beauty’, ‘Claudia Wannamaker’, and ‘D.D. Blanchard’ are three that come to mind and are readily available in the trade. Southern magnolias can reach up to 80 feet tall and 20 to 40 feet wide depending on cultivar and growing conditions. Not only do these three cultivars have beautiful dark green, leathery leaves, their leaves also have brown undersides. These versatile trees can tolerate are variety of soil conditions and they are very wind resistant. And as another bonus, they have beautiful, fragrant flowers.
Middle-aged Juniperus virginiana ‘Burkii’: Burk Eastern Redcedar. Photo Credit: Ed Gilman, University of Florida/IFAS
Eastern redcedar (Juniperus virginiana)
If your looking for softer texture in your landscape, then you can’t go wrong with a cedar tree. Unbeknownst to its name, eastern redcedar can be found growing all over the United States. This evergreen conifer prefers well-drained sites in full sun. It can grow 30 to 40 feet in height by 10 to 20 feet wide. Eastern redcedars have good salt tolerance. These trees produce beautiful, blue-green foliage. One key to growing this tree successfully is to give it space. Plant trees 12 to 24 feet apart. If using as a screen, you may consider staggering this tree to give it the space it needs.
There are lots of good options when selecting trees for a screen. It’s important you select plants that fit the site. The University of Florida has an excellent plant selection tool found at the Florida Trees for Urban and Suburban Sites webpage.
Sweet Viburnum (Viburnum odoratissimum) is thought of as being an ironclad landscape shrub, generally a rapid, healthy grower free of insects and disease. However, this spring, many Sweet Viburnum specimens across the Panhandle have experienced varying degrees of dieback, from individual shoots to entire sections of shrubs, caused by the fungal pathogen Botryosphaeria – commonly known as Bot Rot.
Typical symptom of Bot Rot on Sweet Viburnum. Photo courtesy of Daniel Leonard.
Bot Rot almost always appears after some kind of major stress event that impacts susceptible plants – drought, pruning wounds, nutritional deficiencies, or another environmental stress. We haven’t been afflicted lately with any serious drought conditions and the disease occurrences are too widespread to have been a result of isolated pruning or poor plant nutrition. However, the Panhandle did experience a major environmental event around Christmas 2022 that was plenty stressful for landscape plants, a weeklong Arctic blast of extreme cold. This abrupt hard freeze event in an otherwise mild winter is my best guess for what brought about the increased incidence of Botryosphaeria we have experienced this spring.
The Botryosphaeria fungus enters plants via wounds – in this case one probably caused by cold – and begins destroying the plant’s vascular system in the area. As the pathogen progresses, it eventually causes sunken cankers to appear, girdles the affected branch, and cuts off “circulation” in that stem. The first symptom of Bot Rot that gardeners notice is shoots rapidly wilting and exhibiting a blighted appearance, with brown, dead leaves holding onto affected limbs. Unfortunately, dieback isn’t always limited to individual shoots and can spread back into plants to eventually encompass whole branches. Entire plants dying from Bot Rot infection is not uncommon.
While there aren’t any fungicides that are effective in controlling or preventing Bot Rot, gardeners can arrest its spread by pruning out infected branches. To completely rid the plant of the fungus, make sure to prune 4” or so below the last infected plant tissue (symptomatic tissue will appear dark and discolored; healthy tissue will appear light and greenish). After pruning each affected plant, it is important to sanitize pruning equipment with either a 10% bleach solution or 70%+ isopropyl alcohol to prevent spreading pathogens to other healthy plants! Plants that have been irreparably disfigured by Bot Rot or outright killed may be pulled and discarded offsite.
While this year’s Bot Rot infestation has been extremely frustrating and similar future freeze events can’t be ruled out, gardeners should not give up on Sweet Viburnum, an excellent specimen or screening shrub. Keeping plants healthy with proper pruning, good fertility, and adequate irrigation is the best defense to ward off future infection when we experience harsh environmental conditions! For more information on Bot Rot, Sweet Viburnum, or any other horticultural topic, contact your local UF/IFAS County Extension Office! Happy Gardening.
There are many considerations to make when landscaping with small trees (under 20 feet) in the landscape that are not suitable for large trees. Some of the trees discussed can at times be considered large shrubs depending on definitions and opinions. For the purpose of this article, if it reaches 15 to 20 feet consider it a tree.
Choosing small trees for the right setting involves a number of reasons that could include the need for more privacy from other homes, use as a sound barrier from busy roads, hiding your utility area of the landscape or something unattractive nearby and making sure power lines are not obstructed. Other considerations might include soil types, drainage and holding capacity of the soils, irrigation needs, rate of plant growth and maturity height at 20 feet. Below are a few to consider for the Panhandle of Florida.
Little Gem Magnolia (Magnolia grandiflora ‘Little Gem’) and Teddy Bear Magnolia (M. grandiflora ‘Teddy Bear’) are strong hardy plants once established (within the first 6 months to a year). Both are evergreen with dark green foliage. The ‘Little Gem’ will grow to 20 feet tall by 15 to 18 feet wide. As it matures it tends to become more open and less dense which adds a nice character to show parts of the lower limbs. The ‘Teddy Bear’ will grow to 18 to 20 feet tall but at an even slower rate of maturity to 12 to 15 feet wide while maintaining its density of foliage from bottom to top. It may take a little work to locate the ‘Teddy Bear’ Magnolia.
Photo courtesy: Stephen Greer Teddy Bear Magnolia (Small compact grower)
Several hollies to consider would include the Cassine Holly ‘Tensaw’ (Ilex cassine ‘Tensaw’) and American Holly (Ilex opaca). Both are evergreen and produce red berries during the fall that are bird favorites. They have similar heights of 15 to 20 feet and widths of 10 to 12 feet. Pruning can assist in shaping and slowing these measurements, but keep in mind this will change the look of the tree and create a more formal plant presentation.
Photo courtesy: Stephen Greer Cassine Holly ‘Tensaw’
The Fringe Tree (Chionanthus virginica) has been a popular tree southeast U.S. for many years. It brings a bright spot to the landscape with white flower panicles that cover the tree in mid to late spring depending on location. For a full color effect, plant it with an evergreen hedge behind it. This oval deciduous tree will grow to 12 to 20 by 10 to 15 wide. The dark blue fruit appears in the fall and serves as good bird food source. This fruit is usually hidden behind the foliage. There might even be a nice yellow leaf change in the fall if temperatures and weather allow.
A biologist with Blackwater State Forest checks longleaf pines for signs of red cockaded woodpecker nests. Photo credit: Carrie Stevenson, UF IFAS Extension
Longleaf pine is a granddaddy among the trees of the Southeastern United States, once covering up to 90 million acres throughout the coastal plain. Tall and stately, slow-growing and dense, it was one of the most desirable trees in the forestry and shipbuilding industry for two centuries. Its sap was used to produce turpentine, tar, and pitch, especially to coat and waterproof the bottoms of wooden ships. Its tall, upright form made for a perfect ship’s mast. Between the years 1830 and 1935, approximately 90% of the Southeast’s old growth longleaf trees were harvested, and much of the land was used for farming or development.
Besides its commercial uses, the longleaf ecosystem supports a wide diversity of other plants and animals. The endangered red-cockaded woodpecker nests only in the wood of old (100-500 years!) longleaf pines, and the canopy shades a grassy groundcover often dominated by wiregrass. Gopher tortoises, the endangered indigo snake, and quail also thrive in longleaf pine ecosystems.
A longleaf pine in its grass stage. Photo credit: Carrie Stevenson, UF IFAS Extension
The longleaf pine is highly adapted to fire while in its “grass” stage and as an older tree, allowing it to tower over smaller hardwoods that are cleared out in natural and prescribed fires. This clearing allows its own seeds to sprout and thrive, and for low-growing grasses to dominate the understory. Pines can be difficult to differentiate in the southern forest, but longleaf pines have deep (up to 8-12 feet) taproots and long needles—up to 18 inches—in fascicles of two or three. The needles grow in spherical bunches that look like cheerleading pom poms.
As ecologists and foresters have realized the important role these trees play in the landscape, significant efforts have been undertaken to restore much of that habitat on both public and private land. Locally, Blackwater State Forest and neighboring Eglin Air Force Base have replanted and managed thousands of acres of longleaf habitat. Foresters and nonprofits also work with private landowners to reestablish these stately pines.
