by Rick O'Connor | Apr 8, 2021
EDRR Invasive Species
Beach Vitex (Vitex rotundfolia)
Vitex beginning to take over bike path on Pensacola Beach. Photo credit: Rick O’Connor
Define Invasive Species: must have ALL of the following –
- Is non-native to the area, in our case northwest Florida
- Introduced by humans, whether intentional or accidental
- Causing either an environmental or economic problem, possibly both
Define EDRR Species: Early Detection Rapid Response. These are species that are either –
- Not currently in the area, in our case the Six Rivers CISMA, but a potential threat
- In the area but in small numbers and could be eradicated
Native Range:
Beach vitex is native to the coastal shores of Asian countries bordering the Pacific rim. It is also found in Hawaii.
Introduction:
There are conflicting records as to when it was first introduced to the U.S. One record has it in the country as early as the 1950s. However, there are no records of plants from that stock still existing. Most records suggest the release of the plant occurred in the 1980s when it was brought to North Carolina as a potential ornamental plant. It was then used in dune restoration after a series of hurricanes and became a problem. Thus, it was intentionally introduced.
EDDMapS currently list 649 records of beach vitex. Most are in North Carolina. There are 82 records in Florida and 46 (56%) are in the Pensacola Bay area. We currently have 75 records from the Pensacola Bay area. Not all are reported on EDDMapS due to private property restrictions. Records do occur in coastal Alabama, Mississippi, as well as Okaloosa and Franklin counties in the Florida panhandle.
Distribution is most likely due to the high tolerance of salt water by the seeds and dispersal by currents, as well as intentional plantings by local landscapers and homeowners. Vitex rotundifolia is now a noxious weed in Florida and can no longer be sold.
Within our CISMA there are records in all coastal counties (Baldwin, Escambia, Santa Rosa, and Okaloosa)
Description:
Beach vitex is a perennial plant that initiates from a main taproot and extends herbaceous vines across the surface of the substrate in almost a 360° pattern. The vines can grow as much as 20 feet in length and become more woody with age. As the plant grows, secondary roots extend from each of the nodes from the above ground stems (vines) and becomes more of a shrub, reaching a height of about two feet.
The two-inch leaves are ovate in shape, a light green to blue-green color, and are aligned opposite of each other. They turn a reddish brown during the fall and winter and many plants will lose their leaves completely during this time.
The blossom is a lavender color and made of numerous small petals. The blossoms are present during the spring and summer. They will produce numerous charcoal gray fruits in fall and winter. Each fruit can hold up to four seeds. It has been reported that the plant can produce over 1000 seeds / m2.
Issues and Impacts:
After planting for dune restoration in North Carolina, the plant quickly became a monoculture. It is allelopathic creating a hydrophobic situation in the soil. This situation can cause the decline of native plants, such as sea oats (Uniola paniculata). As the plant becomes more of a shrub it decreases the amount of sunlight reaching the surface further decreasing the smaller native plants and the ability for many to germinate.
This altering of the native dune plant community can have potential impacts on the native faunal communities. There are concerns on its impacts to protected species such as beach mice and nesting sea turtles.
Having a taproot system rather than a fibrous one like the sea oat, can comprise dune integrity during tropical storms. It is known that these dune systems provide protection for natural and developed areas behind them.
Management:
Finding the plants early and removing by hand is the first and best option. The plant is relatively new to the panhandle area and smaller ones are often found. Once the small plants are found, you can simply cut the above ground vine into 2 foot sections and place in a trash bag – you should double bag this. Woody vines may puncture the bag so shorter sections may be needed for those.
Once you reach the taproot you may be able to pull it from the ground, or you may need to dig it out. This method works well in loose dry sandy soils, it may require more digging and cutting if soils are more compacted. If you cannot remove the entire taproot, we recommend spot spraying the remainder with glyphosate. Be careful not to over spray, glyphosate is non-selective and will kill any native plants it comes into contact with.
In cases where the patch of vitex is too large to remove by hand then chemical treatment will be needed. Several studies have been published as to which herbicides are effective. Imazapyr, Triclopyr, and Glyphosate are all products that have been used both in foliage application and cut stem with success. The exact concentrations vary with abundance of plants and surrounding habitats and re-treatments over a few years may be required. We recommend you reach out to your local CISMA or county extension office for more direct help on your situation.
For more information on this EDRR species, contact your local extension office.
References
Invasive Species – Beach Vitex. Rick O’Connor. 2017. UF IFAS Escambia County Blog. http://blogs.ifas.ufl.edu/escambiaco/2017/03/20/invasive-species-beach-vitex/.
Early Detection and Distribution Mapping System (EDDMapS)
https://www.eddmaps.org/
Six Rivers CISMA
https://www.floridainvasives.org/sixrivers/
by Jennifer Bearden | Mar 26, 2021
Cogongrass flowering
We’re waging war on an invasive weed, Cogongrass. Cogongrass was accidently brought into Mobile, Alabama in the early 1900’s as packing material. It was later planted in Florida and other states as a potential forage and soil stabilizer. It has low forage value and is on the Federal Noxious Weed List.
This weed can spread through both creeping rhizomes and seeds. It quickly displaces desirable grasses and plants. The roots of Cogongrass may produce allelopathic chemicals helping it out-compete other plants for space. It is drought and shade tolerant. A single plant can produce 3,000 seeds. Cogongrass is yellow/green in color with an off-set midrib and a fluffy white seed head and it grows in circular colonies.
Mowing and burning will not eradicate Cogongrass instead doing so while the plants are flowering can cause spread of seeds. Herbicide options are non-selective and kill most native ground cover such as grasses. Ridding an area of a Cogongrass infestation requires intensive management. For small infestations (less than 20-30 feet in diameter), treat the area with glyphosate once in the fall and once in the spring for 3 years (or until eradicated). For larger infestations, a more integrated approach may be necessary. Deep tilling of the soil may help in some cases.
Cogongrass is not easy to control. It takes a coordinated effort from government agencies and private landowners to work together to rid an area of this invasive weed. For more information, you can go to https://edis.ifas.ufl.edu/wg202 or contact your local extension agent.
by Rick O'Connor | Mar 26, 2021
Six Rivers “Dirty Dozen” Invasive Species
Cogongrass (Imperata cylindrica)
A relatively new patch of cogongrass recently found in Washington County.
Photo Credit: Mark Mauldin
Define Invasive Species: must have all of the following –
- Is non-native to the area, in our case northwest Florida
- Introduced by humans, whether intentional or accidental
- Causing either an environmental or economic problem, possibly both
Define “Dirty Dozen” Species:
These are species that are well established within the CISMA and are considered, by members of the CISMA, to be one of the top 12 worst problems in our area.
Native Range:
Cogongrass is from southeast Asia.
Introduction:
It was accidentally introduced as an “escapee” from satsuma crates brought to Grand Bay, Alabama in 1912. It was later intentionally introduced into Mississippi in the 1920s as a forage crop and then to Florida in the 1930s for both forage and soil stabilization.
EDDMapS currently list 79,134 records of this plant. All are listed in the southeastern U.S. Most are in Florida and Alabama, but there are records from Mississippi, Louisiana, Texas, Georgia, North and South Carolina.
Within our CISMA there are 13,279 records. This is probably underreported.
Description:
Cogongrass is a perennial grass that can vary in color from a bright-light green when young to a brown-orange when older. It does die back in areas with cold winters and heavy frost and becomes brown. The leaves emerge from the ground in clumps and can reach four feet in height. The blades are 0.5-0.75 inches wide and the light-colored midline is off center. The blades are serrated along the edge. In the spring the grass produces large white colored fluffs of seeds extending above the leaves to be carried by the wind. There are numerous small seeds joined on long hairs of these structures. There is an extensive rhizome system beneath the ground that can contribute to short distance spread.
Issues and Impacts:
The plant spreads aggressively and has been found in ditches, along roadsides, in pastures, timberlands, golf courses, empty lots, and even on barrier islands. It spreads both by seed wind dispersal and rhizome fragmentation. The plant is known to be allelopathic, desiccating neighboring plants and moving in. It can form dense monocultures in many areas.
The serrated edges of the leaves make it undesirable as a livestock forage, a fact not detected until the plant was established. It can cover large areas of pasture making it unusable. In the winter the plant becomes brown and can burn very hot. Timberland that has been infested with cogongrass can burn too hot during prescribed burns actually killing the trees.
It is currently listed as one of the most invasive plants in the United States. It is a federal and state noxious weed, it is prohibited all across Florida and has a high invasion risk.
Management:
The key to controlling this plant is destroying the extensive rhizome system. Simple disking has been shown to be effective if you dig during the dry season, when the rhizomes can dry out, and if you disk deep enough to get all of the rhizomes. Though the rhizomes can be found as deep as four feet, most are within six inches and at least a six-inch disking is recommended.
Chemical treatments have had some success. Prometon (Pramitol), tebuthurion (Spike), and imazapyr have all had some success along roadsides and in ditches. However, the strength of these chemicals will impede new growth, or plantings of new plants, for up to six months. This can lead to erosion issues that are undesirable. Glyphosate has been somewhat successful, and its short soil life will allow the planting of new plants immediately. Due to this however, it may take multiple treatments over multiple years to keep cogongrass under control and it will kill other plants if sprayed during treatment.
Most recommend a mixture of burning, disking, and chemical treatment. Disking and burning should be conducted in the summer to remove thatch and all older and dead cogongrass. As new shoots emerge in late summer and early fall herbicides can then be used to kill the young plants. Studies and practice have found complete eradication is difficult. It is also recommended not to attempt any management while in seed (in spring). Tractors, mowers, etc. can collect the seeds and, when the mowers are moved to new locations, spread the problem. If all mowing/disking equipment can be cleaned after treatment – this is highly recommended.
For more information on this Dirty Dozen species, contact your local extension office.
References
Cogongrass, University of Florida IFAS Center for Aquatic and Invasive Plants
https://plants-archive.ifas.ufl.edu/plant-directory/imperata-cylindrica/
Imperata cylindrica. University of Florida IFAS Assessment.
https://assessment.ifas.ufl.edu/assessments/imperata-cylindrica/.
Early Detection and Distribution Mapping System (EDDMapS)
https://www.eddmaps.org/
Six Rivers CISMA
https://www.floridainvasives.org/sixrivers/
by Rick O'Connor | Mar 11, 2021
EDRR Invasive Species
Giant Salvinia (Salvinia molesta)
Active growing Giant Salvinia was observed growing out of the pond water on to moist soils and emerging cypress and tupelo tree trunks. Photo by L. Scott Jackson
Define Invasive Species: must have ALL of the following –
- Is non-native to the area, in our case northwest Florida
- Introduced by humans, whether intentional or accidental
- Causing either an environmental or economic problem, possibly both
Define EDRR Species: Early Detection Rapid Response. These are species that are either –
- Not currently in the area, in our case the Six Rivers CISMA, but a potential threat
- In the area but in small numbers and could be eradicated
Native Range:
Giant salvinia is from southeastern Brazil and northern Argentina.
Introduction:
Intentionally brought here as an aquatic ornamental plant in the 1990s.
EDDMapS currently list 1,090 records of this plant. Most of those records are from a small location at the lower end of the Colorado River on the Arizona/California border. The remainder are scattered across the southeastern United States. There are 14 records in the state of Florida. Three in south Florida, 11 in north Florida and nine of those are from Escambia County. All records in Escambia County are from the Bayou Chico watershed. It is a freshwater plant and believed to have a low tolerance to saline waters. Though it may not be dispersed by drifting from one water body to another, it could be by wading birds or boats that move from one to another. It is used in the aquarium trade and could be released during tank cleanings.
Description:
The plant resembles the common “duckweed” often seen on ponds, but the elliptical leaves are larger – about 2cm in length. The leaves appear “hairy” and drift on the surface of the water with no roots. They grow in three’s, but the third leave often dangles beneath the water and looks like roots. The hairs on the top of the leaf are in groups of four and the tips touch each other resembling an egg-beater. These are hard to see with the naked eye, but a magnifying glass or photo on your phone and then enlarged will allow you to see this.
It likes slow moving, nutrient rich bodies of freshwater.
Issues and Impacts:
This plant grows very rapidly, spreading by vegetated fragments across the surface of the lake or pond it has infested. It forms dense mats on the surface and can block sunlight to submerged plants and grasses as well as aquatic life, lowering biodiversity. Usually inhabiting low energy ponds and lakes, the dead plant material will decompose drawing down on the amount of dissolved oxygen in the water and potentially causing a large fish kill. The large mats can also clog water intake pipes and, is a threat to hydroelectric dams, and – in some cases – even impede the movement of boats.
It is listed as a federal noxious weed but not a Florida one. It is however, on the Florida prohibited aquatic plant list.
Management:
Step one is to confirm identification. This can be done by contacting your local county extension office. For small amounts the plants can be removed by hand, possibly using a crab net or swimming pool debris skimmer net, and laying it out in the sun to dry. Once dead the plant can then be burned in your outdoor fire pit or bagged and disposed of in the trash.
For large infestations you will need to use a chemical spray. Spraying on a waterbody is very tricky and must be done by a certified person. In Florida, we recommend you contact your county extension office, or FWC (who is currently doing the chemical treatment). Chemical spraying does take multiple treatments and dead mats will drift across the waterbody as this process continues. We recommend you remove the dead mats to reduce the chance of decomposition and dissolved oxygen draw down. Dead mats can be bagged and disposed of with your trash.
We also recommend you report the plant to the national database. You can do this by visiting www.EDDMapS.org. You will need to sign in, but this is important for resource managers trying to track and manage this plant. If you have questions on how to do this, your county extension office can help.
For more information on this EDRR species, contact your local extension office.
References
Giant Salvinia. University of Florida IFAS Center for Aquatic and Invasive Plants.
https://plants-archive.ifas.ufl.edu/plant-directory/salvinia-molesta/#:~:text=Giant%20salvinia%20grows%20rapidly%20and,spreads%20aggressively%20by%20vegetative%20fragments.
Plant Management in Florida. Giant salvinia. University of Florida IFAS Center for Aquatic and Invasive Plants. https://plants.ifas.ufl.edu/manage/why-manage-plants/floridas-most-invasive-plants/giant-salvinia/.
Early Detection and Distribution Mapping System (EDDMapS)
https://www.eddmaps.org/
Six Rivers CISMA
https://www.floridainvasives.org/sixrivers/
by Rick O'Connor | Feb 16, 2021
Six Rivers “Dirty Dozen” Invasive Species
Chinese Tallow (popcorn tree) (Triadica sebifera)
The round-ish ovate leaves of the Chinese Tallow.
Photo: Rick O’Connor
Define Invasive Species: must have all of the following –
- Is non-native to the area, in our case northwest Florida
- Introduced by humans, whether intentional or accidental
- Causing either an environmental or economic problem, possibly both
Define “Dirty Dozen” Species:
These are species that are well established within the CISMA and are considered, by members of the CISMA, to be one of the top 12 worst problems in our area.
Native Range:
Chinese tallow is from eastern Asia.
Introduction:
In China, the plant is cultivated for the production of seed oil. It was first introduced to the United States intentionally in the 1700s as an ornamental plant. It was later used in the production of soap. It is now well established throughout the southeast and spreads very quickly to disturbed areas.
EDDMapS currently list 21,924 records of this plant. All but 10 are listed in the southeastern U.S. There are records in the midwest and in California.
Within our CISMA there are 2084 records. This is CERTAINLY underreported.
Description:
Chinese tallow (the popcorn tree) grows to about a height of 20 feet, but there are some trees growing much taller. The leaves are ovate in shape, smooth margins with a sharp spear-like tip. They are arranged alternately on the branches. The flowers are tiny and emerge from a spike-like structure. They are very popular with bees and other insects. The fruit are produced in clusters of three lobed structures. These seed pods are dark in color, but the white fruit emerges in the fall giving it’s other common name – popcorn tree. The bark of the tree is a light gray color and bark segments are small and outlined in black.
Issues and Impacts:
Currently, the issue and impacts have been debated. The plant is an aggressive spreader, quickly taking over newly disturbed areas and reducing the occurrence of several native plants. Such areas as clearing for new development, agriculture, and prescribed burning of forest lands have all had to battle infestations of this tree. One stormwater drain in the Pensacola area is a complete tallow forest. The plant spreads quickly by seed dispersal from fruit eating birds and cut stumps are known to generate numerous new plants from the underground root system.
Once established the tallow can become a monoculture that is known to be toxic to some livestock and can cause nausea/vomiting in humans. Again, there is the reduction of native plants.
The other side of the story involves its popularity as a pollen plant for beekeepers, and sometimes used – at risk – by cattle for shade in the heat of the summer.
Despite the current debate, Chinese tallow is listed as a Category I invasive plant and a Florida noxious weed.
Management:
Management of this plant can be hard once established. Removing small saplings as they emerge by hand is a good start.
Mowing or burning small trees has been shown to be effective and burning larger trees has worked as well. If burning is not an option, then cutting the tree down as low to the ground as possible, then applying a herbicide to the stump can work. However, cutting alone will not solve the problem.
Herbicide of choice is triclopyr. This can be applied to the leaves directly, but it is recommended this be done in late summer just before the plant goes to seed. If applying to the bark, or a cut stump, it can be applied any time of year. If spraying on the bark, begin at ground level and spray up to 15 inches of the stump. If you have cut the tree, apply to the cut stump immediately after cutting.
The U.S. Department of Agriculture (USDA) is currently working with two possible biological controls. One is a small beetle (Bikasha collaris) that is known to consume the leaves and stems of the plant. The other is the caterpillar of the moth (Gadirtha fusca) who feeds on the leaves. In order for the USDA to release such biological controls they must go through an intensive series of tests to make sure they do not become a problem in themselves. As of the time of this writing (2021) they have completed their trials and the process of releasing is open for public comment until Feb 22, 2021.
For more information on this Dirty Dozen species, contact your local extension office.
References
Chinese Tallow, University of Florida IFAS Center for Aquatic and Invasive Plants
https://plants.ifas.ufl.edu/plant-directory/triadica-sebifera/.
Early Detection and Distribution Mapping System (EDDMapS)
https://www.eddmaps.org/
Six Rivers CISMA
https://www.floridainvasives.org/sixrivers/
