The world of botany has its own version of homeland security: Groups of people dedicated to preventing invasive, exotic plant species from gaining a foothold in this country.

But invasive plants are a lot like terrorists. You wipe them out in one location, they pop up somewhere else. You "defeat" one species, only to see an even more aggressive one take its place.

These are the challenges facing groups like the Georgia Exotic Pest Plant Council, which is holding its statewide meeting Friday at Elachee Nature Science Center, followed by a workshop the next day, on Sept. 20.

Both events are open to the public. Friday's symposium is expected to attract scientists, land managers, foresters, nursery owners and others who work with plants. The Sept. 20 workshop is geared more toward amateur gardeners and private property owners.

"On (Sept. 20), we'll teach people how to identify invasive species and talk about effective but environmentally friendly methods of controlling them," said Cynthia Taylor, natural resources manager at Elachee.

Connie Gray, president of the Georgia Exotic Pest Plant Council, said the average person can benefit from either event, and the approach will not be overly technical.

"(Sept. 20) will be more appealing to a wider audience of the nonprofessional public," Gray said. "But there will be plenty to learn on Friday, too."

Registration for Friday's event, which includes lunch, costs $35 for council members and $50 for nonmembers, but the latter includes a one-year membership to the organization. The Sept. 20 workshop costs $15 for those who attended Friday, or $25 for those who sign up for the workshop only.

Gray said the group decided to hold its annual meeting at Elachee partly because of the nature center's proximity to metro Atlanta and partly because Elachee has undertaken numerous projects to control invasive plants.

"Elachee has done a lot of good work under Cynthia's leadership," said Gray. "It's a beautiful place, and you can see the results of their work."

Elachee created Georgia's first cooperative weed management area, a public-private partnership to help control invasives in and around the 1,500-acre Chicopee Woods Nature Preserve.

Gray said fighting invasive species requires involvement from everyone, not just a handful of scientists. Most exotic species end up in the United States because someone brings them here, either inadvertently or deliberately.

"People are beginning to realize that this is something we all contribute to," she said.

Sometimes the species come in as "stowaways," such as seeds attached to imported lumber. But often they are introduced by landscapers who think the plants will be an attractive garden species, only to have them escape to the wild and begin proliferating out of control.

But Gray said gardening companies are learning to be more selective about the plants they import.

"The green industry was initially skeptical about this problem, but now they're some of our best supporters," she said. "They do not want regulation, so they're trying voluntary initiatives."

Friday's keynote speaker will be James Miller, a research ecologist with the U.S. Forest Service and author of "Nonnative Invasive Plants of Southern Forest," considered the essential guidebook on the subject.

Other speakers represent a variety of agencies, including the University of Georgia, the Nature Conservancy, the Georgia Forestry Commission, the Georgia Department of Natural Resources and the Georgia Green Industry Association.

One session will be about cogongrass, an Asian species that is categorized by the U.S. Department of Agriculture as a federal noxious weed.

"Cogongrass is not big in Georgia yet, but we want to prevent the problem from getting so widespread we can't get a handle on it," said Taylor. "Cogongrass is a threat nationwide, to agriculture and forestry. It's highly flammable."

Like many invasive species, cogongrass spreads by forming dense mats of roots that crowd out native plants.

Taylor said Georgia has already lost the battle with some invasive species, such as kudzu, privet and honeysuckle.

"We've waited too late for some species, as far as eradication," she said. "The best we can do is control them in sensitive areas and important natural areas. But the biggest focus is to try to get the word out about new species like cogongrass."

Gray hopes those who attend the symposium and workshop will share their newfound knowledge with others, because the problem can't be solved unless everyone is aware of it.

"We have a chance to do something about it today, whereas five or 10 years from now we might not," she said.