The hills are alive with the sound of ... kudzu growing. Sorry, this is no Rogers and Hammerstein musical, and I am certainly no Julie Andrews. But the hills are surely, greenly alive with such a fast-growing vine you can almost hear it growing.
Kudzu (Pueraria montana var. lobata) is a fast-growing vine native to Asia that was introduced into the U.S. in the late 1800s as an ornamental plant and for erosion control. While it is both of those things (the purple flower clusters are highly aromatic when peeking out from under the large leaves in late summer), its impact is decimating native species by growing about a foot per day under the right conditions.
It smothers other plants under a solid blanket of leaves, blocking them from needed sunlight. The vines twine around trees and shrubs in a strangle-hold breaking branches and bringing them to the ground under the mass of vines. In the past cold winters would keep kudzu in check but as the weather stays warmer, kudzu can stay on the move taking over everything in its path. The dead vines from previous seasons function as a trellis for this plant to climb up, over and keep on moving.
What to do if it has started moving in on you? Don’t stand still. If it’s small enough, remove it quickly as it won’t stay small very long. It spreads primarily through runners, rhizomes, and vines that root at the nodes of the plant. There can be as many as 30 vines growing (and rooting in again) from a single root crown.
Believe it or not kudzu is not invincible. There are different things that can be done at different stages from herbicides, to biocontrols, to mechanical intervention. That is the concept of IPM – Integrated Pest Management with Multiple Approaches.
Whenever your approach includes chemical control, read and follow the labeling on the product you are using for your safety and success. Foliar chemical applications depend on getting really good coverage of the foliage (leaves). Wet to the point of dripping without wasting the product. Spray at head height, not above and spray while you carefully back through the plant mass so the chemical stays on the plant and not on you. Understand that this is not a “once and you’re done.”
These are big leaves, that shelter leaves underneath from getting good contact with the herbicide. Recall the growth rate and trellis habit mentioned earlier. It will be back. Some of the older vines will have grown into woody trunks. If this is the case on your site you can use the “cut stump” technique, sawing through the vine and painting/squirting herbicide coating the cut area so it soaks in and kills the plant at the tuber.
Biocontrol is another approach, but it’s limited. Kudzu bugs do eat kudzu and other legumes like soybeans, other bean species and wisteria. These little stink bugs will reduce the plant mass but not eliminate it. They can be a nuisance problem in and of themselves. Grazers are another biocontrol method.
Kudzu was once used as a forage to try to feed cattle and sheep. Its forage quality is similar to alfalfa with a protein content of about 15 to 18 percent. Lately another option used with success has been goats. Seriously, grazing goats are effective at eating the vine down especially in areas you can’t access with a sprayer or the lawnmower. After a few years of being eaten to the ground the kudzu can’t recover and dies.
Lastly, there is mechanical intervention. Excavate the tuber with taproot if your area is small. It will take some strong back muscle and a sturdy shovel to get it all.
If the kudzu has gotten a thorough start and you can access it safely, then mow it down to knock it back so it doesn’t spread as rapidly. To find out more information about IPM resources contact your local Extension office.
Minda Daughtry is the N.C. Cooperative Extension Agent-Horticulture for Jackson County.
