It’s hard to miss the clusters of lavender colored flowers that seem to be growing everywhere right now. That’s because they are an invasive wisteria, doing what invasive plants do best: growing everywhere.
Wisteria vine wrapped around tree trunk Photo: Tristan Hansford; Budwood.org
We often notice the invasive Chinese wisteria (Wisteria sinensis) and Japanese wisteria (Wisteria Floribunda) in the early spring because of their fragrant and showy flowers. Look closely, and you’ll see thick vines wrapped around trees, decks, and other structures. This dense growth outcompetes native plants by taking up available light, nutrients, and space. Eventually the vines can even kill the trees and damage structures they grow on.
Look-Alike Alternatives
If you love the look of the invasive wisteria, consider planting the native American wisteria (Wisteria frutescens) to achieve a similar look, without damaging structures or ecosystems. American wisteria is a native plant and a larval host plant for butterflies and moths, including the long-tailed skipper. It grows well in USDA zones 5 to 9.
American Wisteria Photo courtesy of Robert H. Mohlenbrock, hosted by the USDA-NRCS PLANTS Database / USDA SCS. 1991.
Invasive wisteria has larger and less dense flower clusters. Photo: UF/IFAS Lauren Goldsby
Invasive Wisteria Removal
Use the lavender colored flowers in the spring to locate invasive wisteria in your landscape. Invasive wisteria has long flower clusters (up to 50cm) and seed pods that are covered in dense hairs. American wisteria has shorter (5-10cm), denser flower clusters and seed pods that are hairless. If the vine you see is growing aggressively in natural areas, it is likely an invasive wisteria. You can always reach out to your local Extension office for help with identification.
Cut the vine as close to the root as possible and apply glyphosate to the cut stem with a sponge or paintbrush. Invasive wisteria can spread from seeds and stems so be careful to remove all plant material and dispose of it in your garbage not your compost bin. If you do not want to apply herbicide you can still cut the main stem but will need to come back to remove sprouts or dig up and remove the root system.
For more recommendations on vining plants that won’t take over, check out this article: Versatile Vines
Florida’s natural areas—a great source of pride and enjoyment to its citizens—provide recreation, protect biodiversity and fresh water supplies, buffer the harmful effects of storms, and significantly contribute to the economic well-being of the state. Unfortunately, many of these natural areas can be adversely affected by invasive plant species. An estimated 25,000 plant species have been brought into Florida for use as agricultural crops or landscape plants. While only a small number of these have become invasive, Chinese tallow (Triadica sebifera) is one of them.
As the trees begin to turn various shades of red, many people begin to inquire about the trees. While their autumn coloration is one of the reasons they were introduced to the United States, it took years to realize what a menace the trees become. Triadica sebifera, the Chinese tallow is locally referred to as popcorn tree due to the appearance of the developing seed heads, white three-chambers seeds covered in a fatty wax. It was introduced to Charleston, South Carolina in the late 1700s for oil production and use in making candles. However, the seeds are also tasty snacks for birds and can float long distances in the water, enabling it to spread to every coastal state from North Carolina to Texas, and inland to Arkansas. In Florida it occurs as far south as Tampa, displacing other native plant species in those habitats. Therefore, Chinese tallow was listed as a noxious weed by the Florida Department of Agriculture and Consumer Services Noxious Weed List (5b-57.007 FAC) in 1998, which means that possession with the intent to sell, transport, or plant is illegal in the state of Florida.
Fall color of Chinese tallow
Individuals can help mitigate the problem of Chinese tallow trees in Florida’s natural areas by removing them from their property. Mature trees should be felled with a chain saw by the property owner or a professional tree service. The final cut should be made as close to the ground as possible and as level as possible to facilitate application of an herbicide to prevent sprouting. Stumps that are not treated with an herbicide will sprout to form multiple-trunked trees. If it is not objectionable for dead trees to be left standing, certain herbicides can be applied directly to the bark at the base of the tree (basal bark application).
Herbicides that contain the active ingredient triclopyr amine (e.g., Brush-B-Gon, Garlon 3A) can be applied to cut stumps to prevent re-sprouting. The herbicide should be applied as soon as possible after felling the tree and concentrated on the thin layer of living tissue (cambium) that is just inside the bark. Herbicides with the active ingredient triclopyr ester can be used for basal bark applications. Only certain triclopyr amine products may be applied to trees that are growing in standing water. If trees are cut at a time when seeds are attached, make sure that the material is disposed of in such a way the seeds will not be dispersed to new areas where they can germinate and produce new trees.
Space in a landscape left after removal of Chinese tallow can be used to plant a new native or noninvasive tree for shade, or some other landscape purpose. Although Florida is not known for the brilliant fall color enjoyed by other northern and western states, there are a number of trees that provide some fall color for our North Florida landscapes. Red maple, Acer rubrum, provides brilliant red, orange and sometimes yellow leaves. The native Florida maple, Acer floridum, displays a combination of bright yellow and orange color during fall. And there are many Trident and Japanese maples that provide striking fall color. Another excellent native tree is Blackgum, Nyssa sylvatica. This tree is a little slow in its growth rate but can eventually grow to seventy-five feet in height. It provides the earliest show of red to deep purple fall foliage. Others include Persimmon, Diospyros virginiana, Sumac, Rhus spp. and Sweetgum, Liquidambar styraciflua. In cultivated trees that pose no threat to native ecosystems, Crape myrtle, Lagerstroemia spp. offers varying degrees of orange, red and yellow in its leaves before they fall. There are many cultivars – some that grow several feet to others that reach nearly thirty feet in height. Also, Chinese pistache, Pistacia chinensis, can deliver a brilliant orange display.
There are a number of dependable oaks for fall color, too. Shumard, Southern Red, and Turkey are a few to consider. These oaks have dark green deeply lobed leaves during summer turning vivid red to orange in fall. Turkey oak holds onto its leaves all winter as they turn to brown and are pushed off by new spring growth. Our native Yellow poplar, Liriodendron tulipifera, and hickories, Carya spp., provide bright yellow fall foliage. And it’s difficult to find a more crisp yellow than fallen Ginkgo, Ginkgo biloba, leaves. These trees represent just a few choices for fall color. Including one or several of these trees in your landscape, rather than allowing the popcorn trees to grow, will enhance the season while protecting the ecosystem from invasive plant pests.
For more information on Chinese tallow tree, removal techniques and native alternative trees go to: http://edis.ifas.ufl.edu/ag148.
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.
Invasive species are all around us, from invasive plants like cogongrass to invasive amphibians like Cuban tree frogs to invasive insects like red imported fire ants. These species affect our ecosystems by outcompeting native species for nutrients or food and other precious resources. To help with the management of these noxious organisms, the October 2021 edition of Gardening in the Panhandle LIVE educated the public on invasive species. The highlights from the webinar are listed below.
Cogongrass dominating the landscape. Photo credit: Charles T. Bryson, USDA Agricultural Research Service, Bugwood.org.
Beach vitex in bloom is an attractive plant, which can make it more difficult to convince property owners of its harmful potential. Photo credit: Rick O’Connor, Florida Sea Grant
One of the biggest problems with beach vitex (Vitex rotundifolia) is its beauty. It has rounded, deep green leaves (with a silvery gray cast) and a beautiful little lavender-purple bloom. Like most weedy invasive plants, the plant was imported and sold as an ornamental groundcover for many years. Homeowners and landscapers planted it in coastal areas where it is well adapted to the salt and heat, and no one realized it would be so problematic. Ever since, beach vitex took root and has continued growing, unchecked, throughout the coastal south.
In this photo, beach vitex has overrun all native dune vegetation to form a monoculture. Photo credit: Randy Westbrook, Invasive Plant Control, Inc. bugwood.org
North and South Carolina started having big issues first, when beach vitex was planted deliberately to stabilize sand dunes after hurricanes. Soon after, a coastal restoration specialist with the Army Corps of Engineers realized the mistake. The vines run along the ground in such thick mats that native vegetation like sea oats can be choked out. The wide-spreading fibrous roots and tall profile of sea oats hold sand in place better than the beach vitex’s low growth and taproot, which have long term consequences for maintaining dune stability. The thick tangle of vitex growth is yet another obstacle for hatchling sea turtles in a long list of man-made problems that has made nesting and reproduction difficult.
The invasive vine beach vitex has taken over a stretch of sand on Pensacola Beach. Photo credit: Rick O’Connor, Florida Sea Grant
Eradication of the noxious weed has proved difficult. When a plant gets the nickname, “beach kudzu,” you know something went seriously wrong. Beach vitex produces millions of seeds in late summer and early fall, which are dispersed by wind, birds, and float over water. Unless removed before going to seed, even a small patch of the vine can expand rapidly. While not as prevalent in Florida, over 80 sites have been identified in the western panhandle with beach vitex. Due to these problematic issues, the plant was recently added to the Florida Noxious Weed and Invasive Species List, making it illegal to sell, grow, move, or release the plant.
