Filed at 10:11 a.m. ET
WALNUT HILL, Fla. (AP) -- Cogon grass, a fast-growing Asian weed that initially hitchhiked to America as a packing material, is becoming a worse plant scourge than the infamous kudzu vine in many parts of the South.
It kills pine seedlings, is a hot-burning fire hazard, squeezes out native plants and ruins habitats for threatened species such as the gopher tortoise and indigo snake. Cogon is even more aggressive and harder to get rid of than the ubiquitous kudzu.
``There's no pest, disease or fungus that destroys it,'' said Ross Price, manager of a 45,000-acre pine plantation for La Floresta Perdida Inc. ``We can retard it, slow it and stop it, but the word 'control' I don't have.''
Spraying, burning and uprooting have eliminated kudzu from woodlands that Price oversees in the northwest tip of the Florida Panhandle, but cogon remains a growing problem here and elsewhere.
``Kudzu's a weenie plant compared to cogon grass,'' said James H. Miller, research ecologist for the U.S. Forest Service in Auburn, Ala.
Cogon is considered one of the world's 10 worst weeds and has invaded every continent except Antarctica. In the United States, it has spread as far south as the Everglades, up into South Carolina and west into Texas, but Florida is the epicenter, Miller said. Cogon has invaded 30 of Florida's 67 counties.
There are no solid estimates yet on how much land cogon has covered or its costs, but between 500,000 and 1 million acres in Florida have some levels of infestation, said Greg MacDonald, a University of Florida weed scientist.
Miller said a recent survey shows kudzu covering just under a million acres across the South. Kudzu costs $500 million annually by taking crop and forestry lands out of production and for eradication expenses, according to the U.S. Geological Survey.
A thick mat of rhizomes -- stems that creep along the ground -- makes cogon particularly difficult to eradicate. It takes repeated applications of herbicides combined with burning or tilling, with no guarantee the grass won't pop up again.
Cogon, which grows up to 4 feet tall, arrived in 1911 at Mobile, Ala., as cargo packing from Asia. It later was cultivated in central Florida, Alabama and Mississippi for erosion control and forage, although most animals shun the saw-tooth leaves embedded with silica crystals.
``Cogon grass tends to be a problem in low-maintenance areas that are disturbed either through natural or artificial means,'' said Donn Shilling, director of the University of Florida's Mid-Florida Research and Education Center in Apopka.
Forests that have been logged, fire breaks, roadsides, reclaimed strip mines and developed areas are highly susceptible. Shilling, a leading cogon expert, said cogon is seldom a problem, however, on actively managed property such as lawns and crop fields.
The weed cannot tolerate shade but spreads rapidly in sunlight. Unlike kudzu, which can coexist with other plants, cogon excludes all other species except large trees.
``It just tends to dominate,'' Shilling said. ``Kudzu isn't quite that aggressive.''
Kudzu is a fast-growing vine that kills or damages other plants by smothering them with a blanket of leaves or breaking limbs and uprooting trees and shrubs from its sheer weight. It is more cold-tolerant and, thus, has a wider range, but cogon is a bigger problem where both thrive, Shilling said.
Removing cogon from forest land costs $100 an acre to apply herbicide, and at least two treatments are needed, Price said.
``It's not going to put us out of the timber business, but if you're a 20-acre landowner and you've got two acres of it, it's going to really financially impede you,'' he said.
Larger growers instead may have to change management strategies. La Floresta prefers to plant longleaf pine for high-grade lumber and utility poles rather than slash and loblolly pines that produce lower quality wood often used for pulp.
Longleaf, however, takes longer to grow and its seedlings lose the competition for sunlight to the taller cogon.
``Will I ever be able to plant longleaf here again?'' Price asked as he looked over a cogon-infested plot. ``Only if I clear-cut it.''
Price said there's no way he can put a dollar sign on what a change in planting strategy might cost.
Cogon's incendiary nature can cause wildfires -- the weed was blamed for two major blazes near Ocala in 1996 and 2000 -- and complicate prescribed burns.
Fire, natural or controlled, is vital for healthy longleaf ecosystems to get rid of undergrowth that competes with the pines, but cogon burns up to 20 degrees hotter than other plants. That will kill trees such as longleaf pines, which are tolerant of less intense fire.
A common way that cogon spreads is through the transfer of soil and other material infested with rhizomes, and no one moves more dirt than highway departments. That's why cogon is commonly found along roadsides.
Florida Department of Transportation officials realized the seriousness of the problem only when a retired judge threatened a lawsuit about 10 years ago, said Jeff Caster, state transportation landscape architect.
Since then, the agency has trained nearly all employees to recognize the weed, required that sod and hay bales for shoulder stabilization be certified as cogon-free and begun an eradication program, Caster said.
The Florida Department of Environmental Protection has spent about $350,000 over the past six years battling cogon as part of a grant program to control various invasive species on public conservation lands. Private landowners can get financial assistance from the U.S. Fish & Wildlife Service and U.S. Department of Agriculture if they meet certain criteria.
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On the Net:
Plant Conservation Alliance: http://www.nps.gov/plants/alien/fact/imcy1.htm
Florida Division of Forestry: http://www.invasive.org/biocontrol/pdf/28CogonGrass.pdf
