If you have not yet been introduced to kudzu, perhaps you haven’t recently driven many of the roads within Macon County, or through large areas of Western North Carolina. The large-leaf vine has engulfed roadsides and trees, even abandoned cars and homes.
Kudzu is native to eastern Asia and was introduced to the United States at the 1876 Centennial Exposition in Philadelphia as an ornamental plant. It later became popular in the southern United States for erosion control and as forage. However, it quickly became invasive.
One major headache associated with the plant is its rapid growth. Kudzu can grow about one foot each day, easily outpacing competing vegetation or trees around it. Kudzu invades forests by climbing trees and blocking their access to sunlight, eventually killing them.
So how are governmental entities and environmental nonprofits best coping with the headache kudzu can present?
Scottie Coggins, a roadside environmental engineer for the N.C. Department of Transportation (NCDOT) and Kelder Monar, stewardship manager for Mainspring Conservation Trust, provided some insight from their perspectives regarding dealing with the invasive plant.
“Kudzu falls within NCDOT’s vegetation management program, and this program is based primarily on the roadside safety of the traveling public,” explained Coggins. “NCDOT currently uses herbicide applications for areas that are impeding infrastructure, causing a reduction in sight distances at intersections, or covering information signage along the roadway,”
NCDOT schedules these applications once or twice a year, beginning in July; the process usually slows kudzu’s growth – until the first frost stops its growth. In spring, it begins growing again.
“We spray it immediately with herbicide,” said Monar. “For established kudzu infestations, our approach is to target it repeatedly for five-to-10 years, ideally cutting it back mechanically (bush hog) a few times during the summer and then spraying it in the fall with herbicide. Over time we exhaust it.”
He shared, however: “Believe it or not, kudzu is not the non-native invasive plants that we spend the most time dealing with. That title probably goes to Chinese privet or multiflora rose. While kudzu spreads aggressively once established, it tends not to create new colonies in natural areas.”
Other invasive plants that “keep him up a night” include Japanese knotweed, oriental bittersweet, and tree of heaven.
Tackling hearty kudzu
A few different approaches for residents dealing with kudzu on their properties are offered by Mainspring and NCDOT.
NCDOT shared that some proven ways to manage large swaths of kudzu are by using post-emergent herbicides such as Triclopyr for selective targeting or Glyphosate, which eradicates all vegetation (Think Round-Up).
For smaller areas, Coggins listed a few ways property owners can tackle kudzu.
“Plants may be dug up by removing the root crowns, regular mowing and cutting back, and, of course, livestock grazing (goats, especially) can be very effective.”
Monar advised to “prepare for a long fight,” unless an infestation is caught at its inception.
“For a single plant in its first year of growth, spray with herbicide labeled for use on kudzu. Or dig it up, removing the roots. For small or large patches growing on the ground, repeated mowing (or grazing), followed by spray in early fall with herbicide labeled for use on kudzu. Or, manually cut all the crowns or growth nodes, from the roots. If growing up other vegetation, manually cut out or remove kudzu from other vegetation, then the same as the previous option.”
He added that for large vines growing into tree canopy areas, cut as close to the ground as possible, then treat the stumps with a herbicide concentrate labeled for kudzu. For large, complex patches already in trees, a combination of the above approaches is required.
For kudzu, as with many vegetive nuisances, recognizing and addressing the problem earlier is always recommended.