Managing A Stubborn Invasive Vine

By Jean Lynch, Stewardship Project Director, South Region 

kudzu (Photo by James H. Miller, USDA Forest Service)For several years New Jersey Audubon’s Stewardship staff has been working with a landowner in southern New Jersey to improve wildlife habitat. One of the striking problems on this property is a large kudzu infestation affecting the forest edge and the border between forest and field. 

Kudzu is a non-native invasive vine with large compound leaves of three, purple flowers, and long hairy seed pods. Native to Asia, this vigorous vine was originally brought to the United States in the late 1800s as an ornamental plant. The vine was later promoted to help reduce soil erosion and increase livestock feed; however, the fast growing vine had quickly escaped into natural areas, blanketing entire landscapes. In the right conditions, kudzu can grow up to a foot per day by sending out roots wherever the vine touches the ground. As many as 30 vines can then grow from a single root crown, allowing it to easily out-compete native plants. Although primarily found in the southeast, kudzu has been detected as far north as Ontario and is found in several areas throughout New Jersey.

Although tackling an invasive vine like kudzu might appear intimidating to many, we hope you will be inspired by the tremendous progress that we’ve seen in just the two years since the summer of 2012 when the first “before” photos below were taken. At that time, kudzu completely covered many of the trees along the forest edge, and blanketed the field edge. Several of the trees had already died under the blanket of kudzu.

Kudzu July 24 2012NJA_USFWS_forest stewardship_kudzu_controlWith a willing and determined landowner and our partners at the U.S. Fish and Wildlife Service, we decided to take on the challenge of eradicating Kudzu from the property. Getting a handle on this vine has taken planning, the right equipment, and consistent attention, and while our work here isn’t done, the results in just two years are remarkable.

In this and other efforts with invasive vines, we have used a combination of winter work and summer work to good effect. For kudzu, an herbicide mixed with oil (such as triclopyr ester) has been applied directly to the bark or to cut stems during the winter and summer months. Once the vine began to leaf out, the area with lower growing plants is mowed, followed by a foliar application of herbicide mixed with water (such as triclopyr amine). For the higher climbing vines in the tree tops, herbicide is then applied using a high pressure sprayer, curtesy of the U.S. Fish and Wildlife Service. In this instance, the dead vines are left to decompose on site, minimizing its spread into other areas.

After summer spray 2013Kudzu July 30 2014

On average, with a group of two to four people, it has only required about a day of work each winter and two or three half-days of work each summer to achieve the results pictured thus far. With the right equipment and the knowledge of how to effectively combine chemical control (herbicides) and mechanical control (cutting), you can make tremendous progress on even the toughest invasives problems.

You have to be at least as stubborn as the vines!