Kudzu (Pueraria montana) is a rapidly growing vine that has been detected in Michigan but mainly occurs in southern states. There have been four confirmed reports on the western side of Michigan. This vine can grow in a variety of habitats but prefers open and sunny areas. The leaves are comprised of 3 large and smooth leaflets. Once the vines have matured, they change from green to brown and woody. The purple flowers grow on spikes that bloom from August to September.
Hog peanut (Amphicarpaea bracteata) is native to Michigan and is a similar looking vine. The main distinction between kudzu and hog peanut is the flowers. Hog peanut has pink flowers that do not grow on a spike.
If you have seen this species it is extremely important to report it to us or on the MISIN website or the smartphone app. Early detection gives the best chance at treating kudzu.
Environmental effects
Although kudzu is not currently aggressive in Michigan as the climate warms, we expect it to become more aggressive. Kudzu is a nitrogen fixer, so it interrupts the natural balance in soil for nearby native species. Each vine can grow 30 to 120 feet in a year and can have up to 30 vines on each plant. The root system can weigh upwards of 400 pounds. The vines shade out native species and reduces biodiversity. The weight of vines and roots can destroy the buildings it climbs on.
Treatments
Early detection and treatment could prevent the species from rapidly spreading. There are multiple treatment options for kudzu. These include both chemical and non-chemical options.
NON-CHEMICAL CONTROL METHODS:
- Hand pulling: small seedlings can be uprooted by hand. It is important to remove the entire root system otherwise it can resprout. The plant material needs to be destroyed otherwise it may spread at the disposal site.
- Mowing: throughout the year the vines can be mowed to suppress their growth and weaken them. This method is most effective when combined with an herbicide treatment.
CHEMICAL CONTROL METHODS:
- Foliar spray: herbicide is sprayed directly onto the foliage of the vine. This can be effective for large patches and can be done by contractors. Note: any vegetation that is below the vine may also get herbicide sprayed onto it and be killed.
- Cut-stump: herbicide is applied to the outer ring of the cut vine within minutes of making the cut. Note: this should not be done in the spring because the herbicide will be pushed out of the vine.
- Basal bark: herbicide is applied to the entire circumference of the lower 24 inches of the vine. This method is only effective on vines less than 2 inches in diameter. Note: this should not be done in the spring.