Nonnative Species in Florida's Heartland

In Florida, it can be difficult to tell the difference between a plant that simply grows aggressively and one that truly threatens local ecosystems. But for land managers, conservation groups, and scientists across Central Florida, invasive species are one of the biggest environmental challenges facing the region today.

In April 2026, residents and biologists across the five-county Heartland Cooperative Invasive Species Management Area (Heartland CISMA) recognized a major milestone: more than 25,000 observations of introduced species had been documented through iNaturalist. The project, which includes Polk County and surrounding areas, highlights just how widespread nonnative species have become and how valuable public participation can be in tracking them.

UF IFAS Photo by Shannon Carnevale

This milestone is important because tracking all introduced species, also known as nonnative species, is our best early warning system. There is an important distinction to make here: an invasive species is more than simply a species from somewhere else. While a species is considered nonnative simply because it was brought here from another part of the world, to be considered “invasive,” the following must be true.

• The species must be nonnative to the area of consideration.

• The species must have been introduced, intentionally or unintentionally.

• The species causes, or is likely to cause, environmental harm, economic harm, and/or harm to humans.

Florida’s warm climate, abundant rainfall, and extensive trade and travel networks make the state especially vulnerable to invasive plants and animals. By logging nonnative species, community scientists help professionals catch the disruptive species before they get out of hand.

WHAT ARE SOME EXAMPLES OF INVASIVE SPECIES FOUND HERE

Invasive species can be plants, animals, viruses, bacteria, or any other kind of living thing. Two invasive species familiar to many Central Florida residents are cogongrass and the Cuban treefrog. While one spreads silently through fields, roadsides, and yards, the other frequently pops up around our homes, clinging to porches and outdoor lights. Both can disrupt native ecosystems in significant ways.

COGONGRASS

Cogongrass (Imperata cylindrica) is one of the Southeast’s most aggressive invasive plants, and it is practically everywhere in Florida.

Spotting it is easy once you know what to look for. Unmanaged, it covers fields, roadsides, pastures, and more. It’s 2-4 ft tall spring-green grass with fluffy white seed heads. In fall, it can get a bronzed look. Up close, the leaves feature a prominent, off-center white mid-vein and serrated edges reminiscent of native sawgrass.

Polk County land managers actively treat it across the county, but you are just as likely to find it in yards, along lakes, and on fencelines. It can withstand routine mowing for years, slowly expanding outward in a circular pattern until it covers a property. The real giveaway happens if you go out of town for a week or two during the summer. Without constant maintenance, cogongrass shoots up so fast and grows so densely that standard residential lawnmowers can’t easily cut through it … turning a manicured lawn into an exceptionally difficult weed-control battle.

If you think you have cogongrass growing in your yard or on your lakefront, call us at the extension office for recommendations. Treatment is complex and becomes more challenging the larger the patch gets, so don’t wait. Call us at 863-519-1051.

CUBAN TREEFROGS

Another species many Floridians encounter and are usually more familiar with is the Cuban treefrog. Larger than most native treefrogs, Cuban treefrogs are often found around porch lights, garages, outdoor plumbing fixtures, and hiding inside patio umbrellas.

Unlike native treefrogs, Cuban treefrogs prey heavily on smaller frogs and lizards. They also compete with native species for shelter and food. In some cases, they can even clog plumbing or cause failure to electrical equipment. Because they thrive around developed areas, they provide an example of how urban and suburban environments can unintentionally support invasive species. Many communities in Polk County are overrun with this species, and it may be the only treefrog species residents are seeing in their area.

UF IFAS Photo by Tyler Jones

You can recognize Cuban treefrog adults by the color and immense size. These frogs can be over 4 inches in length and are often a light tan or cement grey color with a textured skin. They have very large eyes and toepads. As young frogs, they have reddish eyes and may have an eye band or mask. For information on identifying and removing Cuban treefrogs from your community, visit: ask.ifas.ufl.edu/publication/UW259

WHY IS IT SO COMPLICATED?

One reason invasive species is confusing is that not all nonnative species are harmful. In fact, biologists often point to a general “Tens Rule”: it is estimated that only 10% of introduced species successfully establish themselves in the wild, and only 10% of those become invasive. Ultimately, that means only about 1% of all newly introduced species ever cause problems. When speaking of landscaping plants, this leaves homeowners with a massive variety of safe, beautiful landscaping options that will never threaten our ecosystems.

But for land managers, finding that disruptive 1% requires keeping an eye on the other 99%. That is exactly why the Heartland CISMA project tracks all introduced species, rather than just known invaders. Through iNaturalist and other community science platforms like EDDMapS, Central Florida residents photograph and upload observations from places like Tiger Creek Preserve, Colt Creek State Park, Circle B Bar Preserve, or the Van Fleet Trail. Experts then help identify the species reported which builds a database that supports local management decisions.

Residents can help protect our native species and ecosystems in three major ways:

• Report unusual species sightings through platforms like iNaturalist.

• Remove invasive species from your yard, if found

• Prevent their spread by choosing native or Florida-Friendly landscaping.

As Central Florida grows, public participation is more important than ever. Those 25,000 logged observations are proof that local residents are paying attention and helping protect Polk County’s ecosystems for the future.

For more information about nonnative and invasive species, including recommendations for management, visit my article notes page at https://go.ufl.edu/havenlkld