Kudzu ( Pueraria montana var. lobata) is a highly aggressive invasive vine that earned the nickname “the vine that ate the South” due to its rapid, overwhelming growth. This plant can grow up to a foot a day, quickly smothering native vegetation, trees, and structures by blocking sunlight. The difficulty in eradication stems from its deep, massive root crowns, which are woody, potato-like structures that store significant energy reserves. These energy stores allow the vine to resprout vigorously even after the above-ground foliage has been removed. Effective, lasting control requires a persistent, multi-year strategy focused on depleting these below-ground reserves.
Preparing the Site for Eradication
The initial step in any kudzu control program involves reducing the dense, above-ground biomass to expose the root crowns, which are the primary targets for destruction. Mowing or cutting down large stands of vines is necessary to facilitate the later application of systemic herbicides. This initial reduction makes it possible to locate the individual crowns and ensures that the chemical treatment reaches the intended plant tissue instead of being absorbed by a thick layer of leaves.
Kudzu root crowns are woody knots located at or just beneath the soil surface where the vines originate. In mature patches, these crowns can exceed two inches in diameter. Locating and exposing these structures is important because they must be destroyed to prevent regrowth; simply cutting the vine will not kill the crown. For vines climbing up trees, they should be cut at ground level and again at eye level to prevent the herbicide from harming the desired tree.
Working within dense kudzu patches requires appropriate safety precautions, as the thick growth can hide debris, uneven terrain, and wildlife. Wearing long sleeves, gloves, and protective eyewear is advisable, especially when using power tools. This initial physical effort is a prerequisite for successful chemical treatment.
Targeted Chemical Treatment Protocols
Systemic herbicides are the most effective tool for destroying kudzu’s extensive root crowns by translocating the chemical throughout the plant’s vascular system. Herbicides containing active ingredients like triclopyr or glyphosate are recommended for their effectiveness against this invasive species. The success of chemical control heavily depends on the correct timing and application technique to ensure the chemical is moved efficiently to the root crowns.
The most beneficial time for foliar application, which is spraying the leaves, is typically in late summer or early autumn when the vine is actively moving resources down to the roots for winter storage. Applying the herbicide during this period ensures that the chemical is drawn deep into the root crown, maximizing the impact on the energy reserves. However, a treatment in late spring or early summer, after the leaves have fully expanded, followed by a second treatment in the late summer, can be even more effective.
For smaller, younger patches and new growth, a foliar spray application is the most practical method, requiring saturation of the leaves without excessive runoff. For larger, older vines with thick stems, the most direct approach is the cut-stump treatment. This involves cutting the vine close to the ground and immediately applying a concentrated herbicide solution directly to the freshly cut surface. This method bypasses the foliage and delivers the chemical directly to the plant’s circulatory system leading to the root crown.
Long-Term Monitoring and Maintenance
Eradicating kudzu is rarely a one-season endeavor, typically requiring a persistent, multi-year commitment that can last anywhere from three to ten years. Following the initial chemical treatment, consistent monitoring is paramount because root crowns can enter a state of dormancy after stress. Any new, small growth that appears in subsequent seasons must be spot-treated immediately to prevent the root reserves from being replenished.
Re-sprouting vines or new seedlings should be treated with a foliar spray or dug up to remove the small root crown before they can re-establish a significant root system. The goal is to continuously prevent the plant from photosynthesizing, thereby starving the deep root reserves over time. The establishment of competing, desirable vegetation, such as native trees or grasses, is an important step to discourage re-establishment by shading the ground.
Supplemental methods can also aid in the long-term depletion of the kudzu reserves. Continuous, close grazing by livestock, such as cattle or goats, can be effective if sustained over three to four years, consuming over 80 percent of the vegetative growth. Similarly, persistent, frequent mowing or cutting throughout the growing season will deplete the root’s stored energy. Solarization, which involves covering the area with plastic sheeting, can thermally suppress the crowns in smaller areas.