Kudzu Control Bulletin

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Written by: Matt Nespeca
Invasive Species Consultant
cell: 843-833-5250

Kudzu is an extremely aggressive vine, and infests over 7 million acres in the Southeastern U.S., and it is estimated that kudzu is spreading to 120,000 acres each year. Kudzu can devalue a property in several ways:

• Kudzu will displace native grasses and forbs, leaving nothing more than an unsightly monoculture of kudzu vines and brambles.
• Kudzu will reduce accessibility of a property, making it useless for recreational uses and pursuits.
• Kudzu will kill existing trees and forested cover.
• Kudzu will out-compete new tree seedlings.

Picture 1: Kudzu draping over young trees

In short, kudzu is bad. When a landowner chooses to ignore a kudzu patch, the invasive plant spreads rapidly, impacting adjacent forested areas, fields, pastures, and even home sites. Large kudzu infestations are expensive to control. As a patch grows the cost to control the patch will also grow. For example, a kudzu vine can grow up to 60 feet a year. This could mean that a one acre kudzu patch could potentially become an 11 acre patch after as few as ten years. Conventional herbicide treatments can cost as much as $2000/acre to treat kudzu over the course of several years, so in this hypothetical example, a $2000 expense has ballooned into over $20,000 in expenses. A problem that could have been handled early on with a small investment has now become a major financial burden. In addition to having a large expense to control the kudzu problem, the property could have also lost a significant amount of timber, and severely impacted the beauty and integrity of the land. It pays to control kudzu.

Smaller patches of kudzu can be controlled through manual, mechanical, chemical, or a combination of methods. Consider working with a professional invasive plant specialist to develop a treatment strategy, and to implement control work on patches of kudzu over an acre in size. Large kudzu patches can be dangerous places, with draped ravines, ditches, and uneven ground.

Chemical treatment is the most practical method to eradicate large patches of kudzu. Because of the extensive underground root system of kudzu and layers of thick vegetation, older kudzu patches are more difficult to control than younger patches, and may require more sequential treatments for complete control. A patch may require as many as five to ten years of monitoring, inspection and spot treatment after the initial treatment to get it under control. As with all herbicide treatments, remember to always read and follow herbicide labels and treatment instructions, and get a site-specific prescription from an expert whenever possible.

Foliar treatment Methods

Several products are effective for foliar treatment of kudzu (see Table 1). Applications are most effective when they are made with high volumes of water (more than 50 gallons to the acre). High volume foliar treatments are best made with ground equipment, like a truck or large ATV with a mounted hose reel sprayer. Spray coverage is a very important issue when dealing with kudzu. Kudzu forms multiple layers of thick vegetation, so the treatment must be made at a high enough water volume to carry the herbicides into all layers of the kudzu canopy.

Picture 2: Waccamaw Refuge kudzu patch at Yauhannah Bluff in Georgetown County before treatment	Picture 3: Waccamaw Refuge kudzu patch after two years of foliar treatment with Transline herbicide (grasses, forbs and hardwoods have been released by the treatment)

Each product has different selectivity features, so understanding the condition of desirable trees, vegetation and groundcover on a site is an important factor in the selection of a product and method of treatment. In mature kudzu patches, there is usually very little additional vegetation present except for kudzu, since it smothers most plants. Some foliar herbicides provide excellent selectivity for desirable hardwoods and pines, and careful treatment can reduce the chance of injury to your living and healthy trees. All of the products listed in Table 1 except for glyphosate have some level of selectively for direct application to desirable grasses and some products are even safe for a lot of broadleaf plants as well.

Basal Bark and Cut Stem Methods

Basal bark and cut stem treatment methods allow for a more selective method of controlling kudzu, and are commonly used to either clean up smaller infestations, or for treatment of tree-draped and climbing vines. With smaller infestations, this is a treatment method which can be implemented by a landowner or manager without too much additional equipment.

Basal bark treatment involves the use of products like Garlon® 4 Ultra, which is mixed with an oil carrier, and is sprayed around the circumference of the vine so that the treatment encircles the vine. Treatment of approximately 2 feet of vine length near ground level should be sufficient to top-kill the vine, and it will translocate herbicide downward as well. Pathfinder® II is a ready-to-use formulation that can be used in the same manner.

Cut stem treatment involves cutting a vine at or near ground level, and spraying an herbicide mixture directly onto the cut vine. This can prevent resprouting from the crown.

Both basal bark and cut stem treatment methods can be done during the dormant season, which can allow for easier access to the kudzu patch. In most cases, these methods are used in conjunction with foliar treatment as an integrated approach to controlling kudzu.

Table 1: Some product suggestions for kudzu treatments in different situations

Note: Tordon, Transline, Milestone, Garlon and Pathfinder are trademarks of Dow Agrosciences, Escort is a trademark of E.I. du Pont de Nemours and Company.

When making the decision to control a large kudzu patch on a property, the landowner or manager should be committed not only to making an initial treatment, but to following up on an annual basis to assess follow-up treatment that may be indicated. In almost all cases, multiple treatments will be necessary.

Kudzu eradication can be difficult. It is not uncommon that the landowner ends up spending time and money trying to do the work themselves, only to end up contracting with a professional after a couple years of less than satisfactory results. A kudzu vine can grow 60 feet a year. When a treatment does not adequately cover the infested area, kudzu regrows into the treated areas, and the progress is lost. An herbicide strategy with a large kudzu patch can include several years of sequential treatment to achieve a successful eradication.

About the author: CWC Chemical employs Matt Nespeca as an invasive species consultant. Matt has 12 years of experience in vegetation management, and has worked extensively with complex invasive plant problems throughout the southeast. He worked for 7 years for BASF Corporation as a technical specialist, sales representative and product manager. Matt has a M.S. in Forest Biology from Virginia Tech, and a B.S. in Forest Resource Management from Auburn University. Matt is both a registered forester and commercial applicator, and partners with a network of specialized applicators and professionals to provide results for landowners, land managers and other clients.