Cooperative Extension Service 
Institute of Food and Agricultural Sciences
Hendry County Extension P. O. Box 68 LaBelle, Florida 33975-0068 Phone (863) 674-4092

Hendry County Horticulture News

Exotic Invaders Are a Real Threat

While most of our many visitors are welcome to Florida and make an important contribution to the state's economy, many folks would just as soon a special group of visitors had never graced Florida's sunny shores.

Their brilliant colors and unusual foliage brighten corporate landscapes and residential yards. Many of these plants thrive and bloom much of the year in Florida's warm, sunny climate. Others are tropical plants which can provide an exotic summertime effect in our dry winter season. The trouble is, many of these plants are killing off much of natural Florida.

They are called exotic invasive plants. Invasive plants share several characteristics. They grow quickly, propagate easily, resist native pests, and were introduced to the state without the diseases, parasites and other natural enemies that would normally hold them in check in their natural settings. In Florida,  non indigenous plants are estimated to make up some 25 percent of the total flora.

Further aggravating the situation, invasive exotics grow in a wide range of soils, invade undisturbed habitats, crowd out native plants, alter fire patterns, destroy habitats and food sources for native animals, alter drainage patterns and interfere with water navigation and recreation. Invasive exotic plants are such a problem that more than $20 million is spent yearly by water management districts and state and federal agencies to control pest plants in Florida.

Invasive exotic plants and the destruction they cause is not a problem faced by Florida alone. It's a worldwide problem. According to a  report in the New York Times, one in every eight plants in the world is threatened by non-native plants. About 300 native plants are threatened or endangered in the United States and many of these are native to Florida. The spread of invasive non-native plants is now considered by some experts to be the second most important threat to native species, behind habitat destruction.

"The invasion of noxious weeds has created a level of destruction to America's environment and economy that is matched only by the damage caused by floods, earthquakes, wildfire, hurricanes and landslides," Secretary of the Interior Bruce Babbitt said recently. "This is truly an explosion in slow motion by opportunistic alien species with few if any natural enemies."

The problem is more than a loss of native vegetation. There is a chain reaction. When native insects and animals lose their food and habitat source, they leave an area, or die. Larger animals in the food chain also die off.  In addition, non natives are killing off plants that may have as of yet unknown medical benefits or potential benefits to commerce through chemical compounds.

Invasive plants reached Florida in a number of seemingly innocent ways. Some were brought to Florida as ornamentals to satisfy the desires of consumers who wanted plants from around the world to create lush, tropical gardens in their yards. Others were introduced by well meaning scientists as crops for food, fiber, fodder, or to control erosion. Still others like the malaleuca , were introduced with intent of drying up the Everglades to make it fit for human use.  Whatever the reason, these imported plants grew quickly, but soon escaped and found their way into natural areas.

They are now out of control and will end up costing lot of money to contain.  They will probably never be completely eliminated but hopefully can be managed in away that will minimize their impact on natural ecosystems.

A number of steps can be taken toward alleviating the reverberations that non indigenous species are producing in natural systems. Probably,  first and foremost is education and raising the level of awareness among the public and government officials.  Recognition of the problem will pave the way for further action.  Stronger legislation to restrict the introduction of new species and funding for programs to control established invasive plants is needed.

At this time, the main method of control now is through expensive herbicides. However, an number of groups including the University of Florida, the Florida Department of Environmental Protection, and the U.S. Department of Agriculture are studying alternative management schemes including biological controls - such as insects that eat exotic, but not native plants.

On an individual level, folks can learn to recognize invasive exotic plants and avoid their use in the landscape and eradicate them when possible. Increased use of native plants can help maintain a nice looking landscape while omitting invasive exotic plants. Native plants are acclimatized to Florida and require less water and fewer fertilizers than imported plants to grow well.  We have some beautiful native plants, but the beauty may be more subtle than the exotics.

There are still a wide variety of exotic introductions available to those seeking something a bit more flamboyant that do not share the aggressive tendencies of their invasive cousins.  For assistance in choosing non-invasive exotic plants to incorporate into your landscape plans, feel free to contact the Hendry County Extension Office.  Good luck and good gardening.

Gene McAvoy is the horticulture agent with the Hendry County Extension Service.  Direct your horticulture questions to PO Box 68, LaBelle, FL 33975,  e-mail - or phone 863-674-4092 or  863-983-1598.  You are also welcome to visit the Hendry County Extension Office at 225 Pratt Blvd., LaBelle.   Office hours are from 8:00 - 5:00.

The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity - Affirmative Action Employer authorized to provide research, educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap or national origin.

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