When hearing the term “invasive species”, many think of lionfish, released pythons, and monitor lizards-all the things heard about on the news. But which species does the most damage to Florida’s ecology? The answer may surprise you.
Invasive plants are plants that are non-native to the United States. They are often purposely introduced for agricultural purposes as well as ornamental purposes but have sometimes been accidentally introduced. In fact, one-third of the plants growing on their own in Florida are invasive non-native species.
This may not sound like such an issue, but invasive plants have the abilities to change ecosystems and often times will even push out native plant (and animal) species. In this article, we will be covering some of Florida’s invasive plant species that are commonly used in landscaping, how they affect Florida’s natural wildlife, and what you can do to help.
Camphor Tree (Cinnamomum Camphora)
The Camphor Tree was originally introduced to Florida from Eastern Asia around 1875. When distilling the wood from the tree, camphor is formed. The plants have been traditionally used for medicinal purposes in China and Japan, and the chemical camphor can be found in many over the counter products, such as Vicks VapoRub.
The trees were found to be of little profit in Florida, as China and Japan had already cornered the camphor production market. From there, the camphor tree was sold as an ornamental. The plants are attractive and put off a pleasant smell when the leaves are crushed or branches break, but unfortunately, they can be detrimental to Florida’s native ecosystem.
Camphor trees can grow to around 75 feet tall and have wide-reaching branches that create canopies. This seems ideal for Florida, as shading the sun cools down homes, but this can be dangerous. When many camphor trees grow together in close proximity, they create a dense canopy and shade-out smaller, ground growing plants.
The spread of camphor trees is aided by the plants’ high seed yield. Seeds are eaten by birds and small mammals, which allows the seeds to spread quickly and with ease. The camphor tree is able to acclimate to many environments and can quickly take over areas that have been recently cleared or experienced a burn.
In Polk County, a native Florida plant is in danger thanks to the camphor tree. The Florida Jujube is an endangered plant, native to this county. The introduction of the camphor tree is pushing them out. Sadly, this is something we are seeing more and more of.
It can be difficult to remove a camphor tree from your property. The branches are very weak, and often drop twigs or berries, resulting in many saplings around the base of the trunk. It is recommended after the removal to mow the area until no more saplings return. Cut the tree down as close to ground level as possible and treat the stump with herbicide. Burn the tree debris to destroy seeds or take them to a landfill to ensure they will be buried too deep to sprout.
Melaleuca (Melaluca quinquenervia)
Melaleuca is native to Australia and was brought to Florida in 1906 as a potential source for commercial lumber. It was also planted in the Everglades to dry up the land for development, as well as control the mosquito population. Since then, the spread has been rapid, and today is threatening one of Florida’s most diverse ecosystems.
Melaleuca grows in dense forests, which displaces plants, disturbs water flow, and changes soil conditions. Invasions make areas uninhabitable for endangered species, like the Florida panther in the Everglades. It also poses a threat to migrating birds, who rely on native fruits and seeds during their migration.
The oils present in the plants’ leaves and its dry, paper-like bark allow it to burn at a much higher temperature than most plants, making it a fire hazard, which poses a larger threat to the environment and nearby developed areas. In the springtime, melaleuca puts off a strong smell, which can cause headaches and breathing issues. It’s considered highly allergenic.
Ownership of melaleuca without a special permit is illegal in the state of Florida. If you find that you have a melaleuca tree on your property, the best thing to do is to remove it. Cut the tree as close to the ground as possible and treat the stump with an herbicide. Remove the debris by burning it or taking it to a landfill to ensure it will be buried too deep to sprout.
Old World Climbing Fern (Lygodium microphyllum)
Old World Climbing Fern is an aggressive, quick-spreading fern that forms a thick, suffocating blanket over trees, shrubs, and whatever else is in its path. It is one of the largest invasive threats to Florida.
First recorded in Florida in 1958, 20 years later it was well established and already making an effect on the environment. The fern can climb up trees, and force other plant species to compete with it for light. It smothers ground-dwelling vegetation and can kill fully grown trees. When fires occur, the blankets on the ground create a ladder to help spread fire to the tree canopies, causing more damage and spreading the fire further than it may have reached on its own.
This plant spreads quickly; one fertile leaflet can produce 28,600 spores. Spores are easily carried by wind and water, resulting in further infestation.
It is rare to find this plant growing on properties in well-developed areas, but homeowners living in more rural communities may have this issue. If you come across Old World Climbing Fern, contact an environmental department, water management district, or the Florida Fish and Wildlife Conservation Commission. If self-removal is necessary, the best way to do so is to burn it. But be careful, cleared land makes it easy for another invasive species to take over.
Cogon Grass (Imperata cylindrica)
Cogon grass was originally introduced in the 1930s as potential forage for livestock and solution for soil erosion due to urban development. It was soon realized that this plant was little to no help and was more of a nuisance. The grass grows up to four feet tall and spreads rapidly. It grows in thick, dense patches and displaces the homes of endangered ground-dwelling species, like the gopher tortoise.
Cogon grass thrives in hot temperatures, making it an even larger fire threat. It can survive fires that kill fully grown pine trees. This is due to the fact that most of its biomass is underground, meaning the top can be damaged, and grow right back.
Cogon grass is sometimes found in landscaping, due to its hardiness and resistance to pests. The blades have serrated edges, so nothing will eat it. It may sound like the ideal ornamental plant, but don’t be fooled, it has been labeled a noxious weed by State and Federal agencies.
In fact, cogon grass is such an issue in Florida that it is illegal to sell hay or sod from fields that it inhabits. If you find cogon grass on your property, remove it by pulling it like many other weeds. Take care to pull out as many roots as possible. Continue to pull the seedlings until they stop returning. If left alone, cogon grass will grow in large groups that can take as many as five years of herbicide treatment to remove.
Air Potato (Dioscorea bulbifera)
First found in Florida in 1905, it is unsure what originally brought the air potato to the United States. It’s possible that it was brought over as a possible food crop, but the toxins found in the fruit made it inedible.
Regardless of how it got here, it has now taken over. The air potato’s vines can grow between 70 and 150 feet long and grow as fast as eight inches a day once the plant is established. They climb trees and create a canopy in the trees that forces other plant species to compete for light. The dense blankets it forms can block natural processes like rainfall and fires. The vines overgrow and become so heavy that they break branches, and sometimes topple fully grown trees. They shade out ground-dwelling plants and will sometimes completely alter the ecology.
New plants form from the bulbils (the “potatoes”) that the vine grows. Bulbils range from the size of a marble to six inches in diameter. Even the smallest bulbils can sprout, making it extremely difficult to fight back.
There are many vines growing in Florida, to help recognize air potato if there are no visible fruits, check how the vine is growing. Air potato only grows counter-clockwise.
If you find air potato growing on your property, pull the vines out from where it is growing. Be careful to check that you have removed all bulbils. Pile the vines on the ground and spray them with an herbicide, saturate the leaves as much as possible. The herbicide will be absorbed by the tuber underground, killing the plant. Check the surrounding ground for bulbils that may have fallen from the vine and dispose of them. It is not recommended to pull the vines out from the ground, as the remaining roots will grow back. It will be necessary to reapply herbicide to fully eradicate the plant.
Kudzu (Pueraria montana)
Kudzu was introduced to America at the 1876 World’s Fair Centennial Exhibition. It was originally found useless, until the mid-1930s, when dust storms began. Congress urged the use of kudzu to fight soil erosion. Farmers were offered up to eight dollars per acre to plant the vines. Also advertised as a “front porch ivy”, kudzu had a helping hand in taking over what is now estimated to be 227,000 acres of land.
Kudzu is a rapidly growing vine. Once established, it will grow up to one foot a day. The vine grows over everything in its path and suffocates anything below it. It will wrap around and squeeze tree trunks, break large branches off of threes, knock down phone and power lines, and has been known to uproot trees.
Since its introduction, it has slowly begun swallowing the south. It is currently spreading in Texas, Alabama, Georgia, Mississippi, The Carolinas, and Florida. Its span reaches as far as Nova Scotia, Canada.
Often found growing alongside highways, kudzus growth is aided by airflow. It can handle extreme temperatures, growing in temperatures as low as negative 20 degrees Fahrenheit, and will grow anywhere its roots can reach the soil. Kudzu grows over anything, it’s estimated that power companies spend about 1.5 million dollars a year on repairing power lines damaged by the weed.
A large concern surrounding kudzu is the impact that it may have on national parks. The Vicksburg National Military Park currently has 190 out of its 2,000 acres of land infested. Infestation by this invasive plant threatens these parks’ protected biodiversity and many endangered species.
The most practical removal of kudzu is removing it mechanically. Herbicides have been found to be more efficient, but the environmental and health impact of herbicides and insecticides has been a public safety concern since the early 1970s. It takes 40-80 gallons of herbicide to treat one acre of kudzu for one season.
It’s recommended to cut the vine back and mow the vines to prevent regrowth. All the cuttings need to be removed or destroyed to prevent the vines from re-rooting.
Brazilian Pepper Tree (Schinus terebinthifolius)
Brazilian pepper trees were introduced in the 1840s for ornamental uses. The dark green leaves and bright red berries made it a popular Christmas decoration. The trees grow to about 30 feet tall and are one of the most aggressive non-native plants in Florida.
The plants are native to Brazil but can be found in other parts of South America, such as Argentina. Although they may have been a hit with homeowners for landscaping, these plants are dangerous not only to the environment but also to humans.
It looks like holly but is actually in the poison ivy family. For many people, coming into contact with the sap or berries will cause a painful rash. Some may experience respiratory issues when the plants are in bloom.
The pepper tree is dangerous to any plant community that it invades, but none as much as mangrove communities. Since these plants have a salt tolerance, they are able to take over estuaries and change the ecosystem, pushing out native species, many of which are endangered. Manatees, sea turtles, crocodiles, alligators, and even bottlenose dolphins use the estuaries as a home. These brackish waters are key for juvenile aquatic organisms to grow without the threat of predators in open waters.
When pepper trees invade and push out mangrove trees it affects the organisms who use the roots of the mangrove to lay eggs and small organisms that live within the roots. The pepper trees provide poor habitats for native wildlife.
With no predators, seeds are able to easily spread. They can be carried by water or birds and small mammals, although the berries can make birds sick after ingestion. These factors help make the Brazilian pepper tree the most widespread non-native species growing in Florida.
To remove a tree from your property, make sure you wear gloves to avoid skin irritation. Cut the tree down as close to ground-level as you can, and then dig a 5-10 foot circle surrounding the stump and pry it out. Try to cut through as many roots as possible. Pick any remaining root out of the soil and refill the hole with fresh soil. Watch for regrowth, and pull any saplings seen.
If you really love the look of your Brazilian pepper tree but want to remove an invasive species, try the Dahoon Holly. It is a comparable native plant and has the same great Christmas look.
Chinese Tallow (Triadia sebifera)
Chinese tallow was reportedly brought to the United States in 1772 by Benjamin Franklin, who also introduced soybeans and kale. At the time, it was brought over to be used as a cash crop. The idea was to cultivate the oilseed, but it was found that the plant was useless in agriculture and was from there cultivated as ornamental crops.
The plants became popular thanks to their quick growth, pretty fall colors, and resistance to pests. In fact, nothing eats it, as it has little to no food value for native species and is poisonous to livestock. This has helped the plant spread all across Florida.
Chinese tallow is able to adapt to just about any soil conditions. They are found in wet, dry, and saline environments. It grows in forests, in ditches alongside roads, and just about any place seed sprouts.
The flowers are inviting to pollinators, so fertilization for this plant is easy. Homeowners are urged to remove this plant from their properties if found. Cut close to the ground and treat the stump and surrounding area with an herbicide to kill any seeds that may have fallen off. Keep an eye on the area and pull saplings.
Keep in mind that it is currently illegal to be in possession of Chinese tallow with intent to sell, transport, or plant. If you really love the look of your Chinese tallow, try the bastard copperleaf. The copperleaf is a Florida native within the same family, who has beautiful purple flowers comparable to the Chinese tallow’s.
Mimosa Tree (Albizia julibrissin)
The mimosa tree (sometimes called silk tree) is a very common sight in many parts of Florida. Undeniably beautiful, the trees have been used in landscaping since as early as 1745. While the flowers may be inviting in the spring and summer, come fall the trees lose their blooms and grow 6-inch long, brown pea pods full of seeds.
The seeds themselves cause issues. They are toxic to wildlife and cattle and will also sprout anywhere they can- even cracks in the sidewalk.
Full-grown trees range from 20-40 feet in height and can easily establish itself in many different soil conditions thanks to its nitrogen-fixing abilities.
Although quick-growing, the plants are not very hardy and have a relatively short lifespan as compared to other tree species, only around 20 years. A disease called “mimosa wilt” can be carried by the tree and may be able to infect and kill other surrounding species.
If not in a yard, they are commonly found alongside highways and in disturbed areas, such as recently cleared land.
To remove a mimosa tree from your property, cut the tree down before seeds develop to prevent saplings from growing in the cleared area. Saturate the stump with an herbicide. Unfortunately, mimosa trees can re-sprout from their stumps, so stump grinding or removal may be necessary. Cut or pull any saplings that grow around the area.
There are two native species that are comparable to the mimosa tree. The eastern redbud blooms with pink flowers the same color as mimosas, and sweet acacia blooms with yellow flowers with the same texture and shape of the mimosa.
West Indian Lantana (Lantana camara)
Lantana is one of the most common landscaping plants and has been used as ornamentals since as early as the 18th century. They are hardy, medium-sized shrubs and can be planted in clusters or as singles. As the plant grows in popularity, it has also grown across the state.
Now, many people recognize the lantana as a wildflower, as they are commonly found growing alongside highways, in drainage ditches, and in pastures or groves. The brightly colored flowers attract pollinators, drawing them away from native plants and wildflowers.
Since its spread, it has formed a resistance to herbicides, which allows it to become a growing issue in the agricultural industry, as it is oftentimes found growing in citrus groves.
West Indian lantana is also toxic to livestock and cattle, which poses a threat to the animals in the fields it grows in. Children may also become ill if they eat the fruit that the plant grows.
This species of lantana is the most common lantana sold at garden centers and nurseries. This is largely because native lantana (Lantana depressa) is almost impossible to find due to cross-breeding with the invasive shrub. Native lantana is now listed as an endangered species.
Removal of west Indian lantana is difficult. Because of its herbicide resistance, and growth in delicate areas, the best way to manage the plant is through prevention. Check the genus and species of the plant before purchasing as landscaping and remove the non-native lantana from your landscaping by hand pulling and digging up roots. Dispose of carefully, as to avoid the spread of seeds.
Look for the native option at nurseries, they are often called Pineland Lantana or Gold Lantana. The native lantanas are a great addition to your landscaping to add a pop of color, or in a flower garden to attract butterflies and hummingbirds.
“Small acts, when multiplied by millions of people, can transform the world.” –Howard Zinn
Native plants are a key resource for Florida’s ecosystem and native insect, bird, fish, and mammal species. Non-native invasive plants can leave their effects on the environment, even after they’ve been found and removed. They can change soil conditions, water flow, migratory patterns, and entire ecosystems if left unattended.
To help stop the ongoing spread of non-native invasive plant species, be sure to research what plants are being planted in your gardens. Remove non-native species, replace them with native options, and educate others on the dangers of non-native plants.
By establishing a native plant community, you are also helping to provide food and shelter for hundreds of native and endangered species across the state.