Invasive, or exotic pest plants, such as Kudzu are a growing problem in Alabama. Not all non-native plants are invasive. In fact, a large number of our agricultural crops and ornamental plants are non-native (exotic) in origin. Exotic plants are only a problem when they escape cultivation, spread, and aggressively replace native species. Some are overwhelming entire landscapes.
The Nature Conservancy supports the efforts of the Alabama Invasive Plant Council. The Alabama Invasive Plant Council was established in 2003 as a non-profit statewide organization to:
Six simple things you can do to help stop the spread of invasives and keep our natural communities.
Kudzu (Pueraria montana var. lobata)
Native to China and introduced into the South in the 1930s to 1950s for forage and erosion control, but it was finally realized that it could not be used or contained. This highly recognized perennial vine, “The Vine that ate the South”, continues to spread along edges of forests, pastures, and right-of-ways and around cities and towns. During Spring, kudzu vines can grow up to a foot a day, covering trees, buildings, fences, road signs, and telephone and utility poles. In the late 1980s, a county agent survey estimated about 250,000 acres were infested by kudzu in Alabama. Control treatments have been successful using herbicides, overgrazing, and mechanical root removal.
Tallowtree (Triadica sebifera or Sapium sebiferum)
Native to Eastern Asia and first introduced into South Carolina in 1700s and then spread wider by federally sponsored plantings in the gulf coast during the early 1900s for a failed seed oil industry. This deciduous tree’s colorful fall foliage and rapid growth has made it a popular landscape tree. Prolific seed production and dispersal by birds and water has resulted in increasingly infested stream banks, riverbanks, and wet areas as well as upland forests, especially in southern Alabama. This aggressive species is replacing valuable bottomland forests and has limited value for honey production. Several southern states have banned or in the process of banning sales of this species. Plants are controlled by application of herbicides to foliage, stems, or cut stumps.
Cogongrass (Imperata cylindrica)
Native to Asia and introduced into the Mobile area in early 1900s, this tall perennial grass with yellowish foliage forms dense circular infestations that exclude all native species had has no known uses. It is highly flammable and poses a severe fire hazard. Over half of Alabama’s counties have cogongrass infestations with the most severe being in the southern tier of counties. Cogongrass is steadily spreading northward by windblown seeds, movement of contaminated fill dirt, and probably through horticultural plantings (commercial red variety) as well as hay, pine straw, and straw sell from infested areas. This is a federal and Alabama State listed noxious weed. Successful eradication is achieved with multiple herbicide treatments over several years.
Chinese Privet (Ligustrum sinense)
Native to China and first introduced into the United States as an ornamental shrub in 1853. This mostly evergreen shrub has been a traditional ornamental hedge species and continues to be sold and planted principally as the variegated variety. It spreads across the landscape by abundant seeds carried by birds and water, while infestations grow by prolific root suckering. Chinese privet is just one of several species of privet invading Alabama’s fencerows, forested creek bottoms, and upland forests. The dense stemmy infestations reaching 30ft tall displace most native species and prevent regeneration of bottomland hardwood and upland pine forests. Chinese privet has some value as an ornamental, deer browse, and bird habitat. Plants are controlled by application of herbicides to foliage, stems, and cut stumps.
Tropical Soda Apple (Solanum viarum)
Native to Brazil and Argentina, the tropical soda apple was first found in Florida in 1988 and Alabama in 1994. This thorny perennial shrub invaded an estimated 1 million acres in five southern states within 7 ears after its arrival. Over 15,000 acres are currently infested in Alabama with extremely rapid spread underway. Entire pastures are occupied following an initial plant. It migrates by interstate movement of cattle, hay, and composted manure from infested areas, while local spread by wildlife is now suspected. This is a federal and Alabama State listed noxious weed. Eradication requires multi-year application of herbicides.
Japanese Climbing Fern (Lygodium japonicum)
Native to Asia and Australia and introduced into the United States in 1930s, this perennial viney fern is rapidly spreading by windblown and water carried spores, shipments of contaminated pine straw throughout Alabama. Although dying back each winder, prior year’s vines provide a trellis for expansive new growth that eventually covers shrubs and trees. Native species of plants are displaced, wildlife habitat is destroyed, and access to lands is denied by this species. Range expansion could now be stopped or slowed by control of scattered infestations. Careful prescribed burns can reduce vines and applications of herbicides to foliage can control underground stems.
Invasive Roses (multiflora rose/Rosa multiflora, Cherokee rose/R. laevigata, Macartney rose/
Native to Asia and introduced into the United States in early times as ornamentals, livestock containment and wildlife habitat plantings, these roses are increasingly invading pastures, forest edges, right-of-ways, and wetland habitats displacing native species. Cherokee and Macartney roses are evergreen and multiflora is deciduous, but all for impenetrable entanglements that stop land use and management. Cherokee rose is a major plant pest in the Blackbelt, while multiflora and Macartney roses occur throughout Alabama. Effective eradication can be achieved with repeated herbicide applications, while bio-control agents will weaken plants.
Eurasian Water Milfoil (Myriophyllum spicatum)
Native to Eurasia and introduced into the United States in the 1940s as an aquarium plant. This submersed, mat-forming perennial remains green during winter and occurs throughout Alabama in both fresh and brackish waters. It is an aggressive invader of reservoirs, rivers, and lakes. It forms dense mats that replaces native plants and prevents light penetration causing fish habitat destruction. It spreads by plant fragments hitch-hiking on boats and trailers, but also produces seeds. Carefully planned herbicide applications can reduce infestations in some cases.
Hydrilla (Hydrilla verticillata)
Native to Asia or Africa and first introduced into Florida in the 1950s or early 1960s, this submersed herbaceous plant infests fresh-water ponds, rivers, and lakes. Like many invasive aquatic plants, the aquarium trade introduced hydrilla and now spreads by plant parts hitchhiking on boats and trailers. Dense surface mats of hydrilla crowd out native plants and cause reduced oxygen conditions unsuitable for fish. The mats interfere with water flow, drainage, navigation, and often harbor mosquitoes. This is a feral and Alabama State listed noxious weed. Carefully applied herbicide applications can reduce infestations.
Alligator Weed (Alternanthera philoxeroides)
Native to South America and introduced into the United States in the 1890s in ship ballast water, this herbaceous freshwater perennial invader forms dense mats in water bodies, wetlands and low-lying as well as upland areas. The thick mats in water replace native species and can result in fish kills and prevent recreational use as well as slow drainage that may cause flooding. Dense upland infestations make the land useless for any type of productions. A South American flea beetle introduced in the 1980s in Florida for biological control of alligator weed has reduced the spread but is less effective in central and northern Alabama because of low over-winter survival. Several herbicides are available for effective treatment of alligator weed. Eradication requires multi-year applications.