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Photo by John D. Byrd, Mississippi State University, Bugwood.org
Cogongrass is considered one of the 10 worst invasive weeds in the world and is illegal in South Carolina. It destroys wildlife habitats, is unpalatable to animals and poses a fire hazard.
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Photo by Theodore Webster, USDA Agricultural Research Service, Bugwood.org
Benghal dayflowers can be identified by their petite violet blooms and the red hairs on their leaf bases.
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Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Fig buttercup spreads rapidly in wetlands and moist areas, choking out native species.
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Photo by David J. Moorhead, University of Georgia, Bugwood.org
Left unchecked, white-flowering Bradford pear trees (also called Callery pear) can take over a wide swath.
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Photo by Jerry Asher, USDI Bureau of Land Management, Bugwood.org
Kudzu is recognized by its three-leaflet leaves, tiny lavender flowers and rapid growth rate, overtaking other plants and structures in its path.
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Control invasions of unwanted plants by using a hack-and-squirt method, applying small amounts of undiluted herbicide directly to shallow cuts around the base of the trunk.
Alien invaders surround us, lurking in our own backyards. They multiply and seize new territory, forcing out native inhabitants. They may masquerade as beautiful creatures, but don’t be fooled: They are harmful.
These space invaders are exotic invasive plants, consuming resources and causing ecological and economic harm. With some, like kudzu, the damage is obvious. Others might not seem threatening but can be just as destructive. Thorny Bradford pear seedlings have been known to puncture tractor tires and take over fields, reducing property value. Chinese privet can grow into tough thickets, crowding out native plants and animals.
Dozens of invasive plants are at large in South Carolina. Most were introduced for legitimate reasons: kudzu as a forage crop for livestock, privet as an ornamental hedge and Bradford pear as a flowering landscape tree. Many are so well established, it’s doubtful we’ll ever eradicate them. Others, just taking root here, might still be kept under control.
These newer invaders, such as fig buttercup, Benghal dayflower and cogongrass, stand ready to wreak havoc on natural, agricultural and residential areas if not controlled. They compete with field crops and native wildflowers. Cogongrass poses a special hazard—it carries fire easily, increasing the risk of disastrous wildfires. Both cogongrass and Benghal dayflower are regulated species, designated as illegal to sell or move in South Carolina.
Fortunately, several state agencies and nonprofit groups are actively combating these pesky weeds. You can help.
First: Don’t plant these damaging invaders. Some nurseries still sell them, including Bradford pear, English ivy, heavenly bamboo (nandina) and Chinese privet. Internet sales make it easier than ever to purchase plants from other lands, some of which may become invasive enemies.
Next, learn to identify common invasive plants in our state. One good resource is the newly revised book Exotic Invasive Plant Species of South Carolina. It’s available for free by calling your local Clemson Extension county office or by emailing the S.C. Exotic Pest Plant Council. You can also view a current listing of invasive plants in S.C. online at the council's website.
There’s a good chance one or more of these plants are already growing on your property. If so, what should you do?
Your first technique is observation. Keep watch for early infiltrators that show up as seedlings and suckers. Young weeds can easily be pulled or dug out by the roots and destroyed. Once they gain a foothold, however, they are much harder to defeat. If you suspect an infestation of a regulated species, contact the Clemson University Invasive Species Program at (864) 646-2140 or by email before taking any action. Learn more about the program at its website.
Mature invasive trees, shrubs and vines require heavy artillery—uprooting with large equipment and/or applying chemical herbicides. For herbicides, you can broadcast spray the plants’ leaves with diluted rates of a commonly available product containing glyphosate or triclopyr or a three-way herbicide that contains 2,4-D amine, dicamba and mecoprop. These are often labeled in stores as “brush killer.” Get a list of available herbicides that work on most woody invasive plants in the Clemson HGIC Fact Sheet 2307, "Poison Ivy." Be sure to read the label directions for all herbicides, and follow their instructions for appropriate application rates and timing, equipment recommendations, and safety measures.
Broadcast spraying is effective but may require multiple applications. The biggest downside is the potential for friendly fire—spray can drift, harming or killing desirable plants nearby.
A safer treatment is a hack-and-squirt method. It reduces the risk of friendly fire, because you are applying small amounts of undiluted herbicide directly to targeted plants. Cut back the invading plant near the ground or at an easily accessible spot, and squirt or paint herbicide concentrate onto a freshly cut stem or stump. Do it while the cuts are still fresh and damp for more rapid uptake of the herbicide. For larger shrubs and trees, make several shallow cuts around the lower trunk, just above the soil, and apply concentrated herbicide to fresh cuts. This helps kill the roots and stumps and reduces resprouting.
Public awareness, participation and persistence are critical weapons in the fight against invasive species. Educate yourself about these garden bullies, and avoid purchasing, sharing or planting them in our state.
S. CORY TANNER is an area horticulture agent for Clemson Extension based in Greenville County. Contact him at shannt@clemson.edu.
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Get More
Exotic Invasive Plant Species of South Carolina is available for free by calling your local Clemson Extension county office or by emailing the S.C. Exotic Pest Plant Council.
View a current listing of invasive plants in South Carolina at the S.C. Exotic Pest Plant Council's website.
For a list of available herbicides that work on most woody invasive plants, see Clemson HGIC Fact Sheet 2307, "Poison Ivy."
Report infestations to the Clemson University Invasive Species Program. You can also call (864) 646-2140 or visit the program’s website.