Controlling Non-native Invasive Plants in Ohio’s Forests: Kudzu (Pueraria lobata) (2024)

Kudzu (Pueraria lobata) is a non-woody, leguminous vine native to Asia. It was introduced to the United States through the Philadelphia Centennial Exposition in 1876. Following this introduction, it was planted across the southern United States as an ornamental plant, as livestock forage, and for erosion control. This is an aggressive plant capable of rapid growth. It roots sporadically as it covers an area, and layers vines and foliage on top of each other. It orients each leaf for maximum sunlight absorption. This multi-directional orientation of leaves poses special problems with respect to the application of herbicides. Due to its rapid growth and ability to quickly dominate sites, Kudzu is one of the most invasive plant species in the world. Kudzu is listed as an invasive plant in Ohio. Its sale, distribution, and cultivation is banned by the Ohio Department of Agriculture (Invasive Plant Species, 2023).

Identification of Kudzu

Kudzu leaves grow in an alternately compound fashion. The leaves are green to dark green, are 3–4 inches (8–10 cm) long, and have three oval- to heart-shaped leaflets. The leaves may be slightly or entirely lobed (Figure 1). Kudzu stems have fine to coarse hairs (Figure 2) (Byrd, et al., 2024).

Kudzu produces flowers mid-June to mid-July. Its flowers tend to be white, pink, or magenta and are very fragrant (Figure 3). Seedpods mature in late summer to early fall and are approximately 2 inches long, hairy, kidney shaped, and grow in groups of three (Figure 4) (Byrd 2021).

In the Southeastern United States, vines can grow up to a foot a day. Growth rates in Ohio are unknown but are likely to be slower than those in the Southeastern United States. If left untreated, Kudzu has the ability to overgrow fields, trees, and utility poles (Figure 5).

Kudzu Control

CHEMICAL

As Kudzu ages, it becomes more difficult to control. Kudzu produces substantial amounts of above ground stems (vines) and foliage, which makes control difficult. It also produces an extensive root system. The larger and more numerous the roots, the harder Kudzu will be to kill. At a minimum, control requires an initial treatment with at least one follow-up spot treatment. In severe cases, follow-up spot treatments may be needed for up to 10 years following the initial treatment.

The entire root system must be killed to totally control this plant. Control is expensive, but no alternative is available—either control Kudzu or lose the land for other uses, including timber production.

Many herbicides have been evaluated for Kudzu control. Application rates and methods for selected herbicides can be found in Table 1. Since Kudzu is found in diverse landscapes, many different treatment strategies may be required. Table 2 provides herbicide recommendations for specific control situations.

HERBICIDE APPLICATION TECHNIQUES

Application technique is critical for Kudzu control due to the layering of growth and the multi-angle orientation of the foliage. Thorough coverage is essential for good control. Open patches should be treated with a crosshatch spray pattern. First, the outside perimeter of the spray area is treated, and then the area is covered by spraying parallel swaths. Half of the total solution should be used for this coverage. The remaining half of the mixture should be applied in spray swaths perpendicular to the initial coverage (Figure 6). The total volume of the spray mixture varies between applicators, but 40–80 gallons per acre is a consistent recommendation, with 40 gallons per acre being the absolute minimum required for adequate coverage. Near streams, where crosshatch spraying would be difficult or impossible, parallel swaths can be used to follow the stream course. These swaths should be run so that double overlap occurs to get the best coverage.

RETREATMENT

Additional herbicide treatments are not usually made until the growing season after the initial treatment. Retreatment may entail another broadcast application (in the case of difficult patches) or spot treatments to control isolated resprouts. After treatment, it is possible that re-sprouting may not occur until the second growing season. The patch should be checked annually for a minimum of three years for best results.

MECHANICAL

Mechanical methods for controlling Kudzu may have some success in areas that can be grazed, mowed, or cultivated. Mechanical methods include root raking and removing Kudzu root systems by hand. For any mechanical method to work, as much of the root system must be removed as is possible. Stems must be removed as well, as they are capable of sprouting.

In some areas of the south, Kudzu patches are grazed by cattle or goats. This works to clean the site of vines, but long-term control is not likely achieved using this method alone. However, grazing can help keep the Kudzu from spreading.

Additional Resources

Check out the following resources for more information on Kudzu control:

• MP44 Arkansas 2024 recommended chemicals for weed and brush control
• Kudzu
• Beware! Kudzu is thriving in Indiana
• Escape of the invasive: Top six invasive plant species in the United States

References

Byrd, J. D., Winters, F., & Bryson, C. T. (2024). Mississippi’s 10 worst invasive weeds (Publication Number: M1194). Mississippi State University Extension.
extension.msstate.edu/publications/mississippi%E2%80%99s-10-worst-invasive-weeds

Invasive plant species, Rule 901:5-30-01. Ohio Administrative Code. (2023).
codes.ohio.gov/ohio-administrative-code/rule-901:5-30-01

Londo, A.J., & Ezell, A. W.. (2004). Effective kudzu control. Management Technical Note 11F. Department of Forestry, Mississippi State University.