Plants are introduced to environments both intentionally and unintentionally for various reasons.
More than 4,000 plant species are found in Florida and 1,300 of these are non-native or exotic; meaning they have been introduced either from other states or other countries.
< Pictured to the right is Dr. Prince holding two of Florida's invasive aquatic plants: waterhyacinth (left) and water lettuce (right).
Coral ardisia (Ardisia crenata)
Native to: Japan to northern India
TOXIC TO LIVESTOCK. Coral Ardisia is a small upright shrub that is used and sold extensively in the horticulture industry as an ornamental plant (often sold as Christmas berry).
Waterhyacinth (Eichhornia crassipes)
Native to: South America
Waterhyacinth was introduced into the U.S. in 1884 at the Cotton States Exposition in New Orleans as an aquatic ornamental plant. This plant forms dense, impenetrable mats which clog waterways, making boating, fishing and almost all other water activities, impossible. It also reduces biodiversity by crowding out native plants at the water's surface and below.
Water lettuce (Pistia stratiotes)
Origin: Africa or South America
Introduction to Florida: pre-1765
Water lettuce is a floating plant. Experts disagree as to whether water lettuce is native to the U.S.: it has been present in Florida since as early as 1765 when the explorer, William Bartram, described and drew the plant in Lake George. This floating plant commonly forms large infestations which prevent boating, fishing and other uses of lakes and rivers. Water lettuce occurs in lakes, rivers and canals, occasionally forming large dense mats.
Mexican petunia (Ruellia simplex)
Native to: Mexico, Western South America and the Antilles
The wild form has purple flowers, and was introduced to Florida in the 1940s. Mexican-petunia is able to tolerate a wide range of environmental conditions including variations in light, temperature, and moisture. Other characteristics that make wild Mexican-petunia a successful invasive are its rapid growth rate, affinity for disturbed locations, prolific production of seed, and lack of germination requirements such as scarification or stratification.
Tuberous sword fern (Nephrolepis cordifolia)
In 23 counties from the Gainesville area south, specimens of sword fern have been found and documented. Now considered a Category I invasive species, sword fern has made its presence known and continues to spread across Florida. The sword fern poses a threat on native species. Through its aggressive spread, sword fern is able to form dense stands and quickly displace native vegetation.
Nandina (Nandina domestica)
Origin: China and Japan
Introduced to the United States in: 1804
This plant has many uses in the garden as the foliage and fruit are particularly attractive and desirable to homeowners. However its ability to grow tall quickly and reproduce by seed and root fragments becomes a major nuisance for most avid gardeners. Nandina has been placed on the Florida Exotic Pest Plant Council’s invasive list as a Category I species.