Kudzu | Types, Propagation, Problems, and Uses

Kudzu represents plants of the genus Pueraria. This genus is famous for its vine and climbing nature. These are perennial vine plants. They climb and cover other woody plants and due to this covering nature, they absorb most of the sunlight. Which might prove to be killing the woody plants of the area.

They belong to the Fabaceae family which is famous for its legume plant species. The subfamily of Fabaceae, Faboideae includes kudzu plants. The other common names for kudzu plants are the Chinese arrowroot and the Japanese arrowroot.

These plants are abundantly found in the Indian and Chinese subcontinent of the East Asian region. Among all species, Pueraria Montana is most abundantly found in regions of Atlanta and Georgia. The vines are said to be semi-woody.

A particular phenomenon is related to this genus of plants, termed smothering. It is the process of covering the main woody plant of the region with its vines and leaves. It results in a decreased supply of sunlight to the canopy of main woody tree plants. In the end, due to a consistently decreased supply of sunlight, the tree plants become unable to produce enough food for a longer period, and ultimately the plant dies. The majority of the tree is damaged by the mechanism of smothering.

The following figure shows the tree plant and rocks covered with Kudzu.

Some of the species are edible too. But the majority are taken as weed plants. Because these vine plants damage the growth and production of crop plants or tree plants. Farmers get rid of the kudzu plant just by spraying weedicides. A term used for the effect caused by these vines is ecological damage. Which again refers to the smothering phenomenon. Also, it can trigger soil changes leading to climate change as a whole.

As it belongs to the subfamily of Fabaceae (legume plants), that’s why they have a strong role in nitrogen fixation. This group of vine plants has deep root systems so, it becomes quite a difficult task to de-root it. The beneficial aspect of its roots is they save soil from water or wind-based erosion and soil loss^[1]Harron, P., et al., Predicting Kudzu (Pueraria Montana) spread and its economic impacts in timber industry: A case study from Oklahoma. PloS one, 2020. 15(3): p. e0229835. Read.

Types of Pueraria

There are 4 major species and varieties of Pueraria. Some of these are described below related to their basic appearances, roles, and features:

1. Pueraria Montana

This species of Pueraria is easily grown in regions having temperate to warmer weather. There is a great resemblance of its flower with legume flowers, especially with pea flowers. The specific feature of its leaves is the shape and arrangement which give this plan clear discrimination to this plant.

Trifoliate leaves originated from the fusion of three leaflets. It is a climbing vine and can get up to any surface, walls, trees, and rocks. Flowers are mostly in red, purple, yellow, and reddish with a sweet fragrance. This variety is propagated asexually by cloning and sexually by the natural process of pollination. The common term used for this is ‘vine eating south’^[2]Sage, R.F., et al., Kudzu [Pueraria montana (Lour.) Merr. Variety lobata]: A new source of carbohydrate for bioethanol production. Biomass and bioenergy, 2009. 33(1): p. 57-61. Read.

2. Pueraria Phaseoloides

The basic features of the species Pueraria Phaseoloides are similar to Pueraria Montana. The important use of this species is as a forage crop or cover crop. Animals are grazed over this vine plant. It is native to almost all areas of South Asia and temperate regions of America and Australia. Its leaflets have an oval to a triangular shape and it can grow on any surface of any shape and height.

Its growth is quite rapid as compared to other family members. And it has that deep root system helping it to survive in strong winds or lower groundwater levels. This also provides soil protection against wind and water erosion^[3]Clermont-Dauphin, C., et al., Dinitrogen fixation by the legume cover crop Pueraria phaseoloides and transfer of fixed N to Hevea brasiliensis—Impact on tree growth and vulnerability to drought. … Continue reading.

3. Pueraria Tuberosa

The Pueraria Tuberosa is found in Pakistan, India, Nepal, and China. This species is famous for its heavy and expensive tubers. Long penetrating roots develop in juicy tubers extracting fluid used in Ayurvedic medicines. Its leaves are also trifoliate and each leaflet is oval-shaped with round edges.

Flowers are also used for extracting medicinal compounds from them. It is said to be one of the sacred and holy plants for the Hindu nation. Its climbers are famous for damaging higher plants of economic importance^[4]Bharti, R., et al., Pueraria tuberosa: A Review on Traditional Uses, Pharmacology, and Phytochemistry. Frontiers in pharmacology, 2021. 11: p. 2104. Read.

4. Pueraria Mirifica

The common name for this species in Thailand and its neighboring country Myanmar is Kwao Krua Kao. It is mostly found in the above countries along their northern borders. The common name Kao represents its white color which makes it unique when compared with the relatives from its genus.

Its dried powders are also consumed as traditional medicines. Latin name Pueraria Mirifica translates as a boy with marvelous characters. Its extracts are used for increasing breast size, reducing skin problems, and improving nail and hair health^[5]Ingham, J.L., S. Tahara, and S.Z. Dziedzic, Coumestans from the roots of Pueraria mirifica. Zeitschrift für Naturforschung C, 1988. 43(1-2): p. 5-10. Read.

Propagation methods for kudzu (Pueraria spp.)

1. Propagation by seeds (sexual method of cultivation)

The Pueraria species can be spread by the cultivation of seeds. The seeds are produced inside thin and long sacs termed pods. It is here to clarify that all the seeds produced in the 2-inch pods are not viable. It is said that only 2 of them are viable. This viability and germination depend upon the breaking of seed coats. This happens in continuous physical stress or thermal stress that helps the seed coat to break. This results in germination otherwise, the seeds remain dormant naturally.

2. Vegetative propagation by root crown (asexual method of cultivation)

When the seeds are not enough for natural propagation due to their natural dormancy behavior, there arises the need to develop a new and asexual method for the propagation of Kudzu.

The horizontal spread of roots and stems on the surface of the soil leads to the production of new roots and from this new shoots also develop. The roots penetrate deep to keep the plant stable in strong winds and heavy rain^[6]Gao, C., et al., Research status on rapid propagation technology of kudzu vine. China Herbivore Science, 2015. 35(4): p. 64-66. Read.

How to get rid of unwanted Kudzu vines

1. It has damaging effects on the other three plants as a whole. So there are several ways to get over the smothering problem caused by Kudzu vines. An easier method without using any chemicals to decrease the growth of Kudzu is the regular cutting of its foliage. When the foliage is cut down, the plant uses its starch and by using the reserved starch storage it starts to regrow its foliage. The repeated cutting of the foliage helps to decrease the storage in the reservoir (roots). This reuse of the stored food supplements to grow its leaves leads to the complete diminishing of the reservoir. Further cutting of leaves and foliage will not be covered by the stored starch. The plant will run short of the food produced by leaves when the leaves are not there. Instead of cutting, one can also allow the animals to eat the kudzu as forage, and feeding on this will help them with healthy animals and it will also remove the overgrowing kudzu from the concerned area.
2. A fungus named Myrothecium verrucaria has been identified as having natural herbicidal properties. The chemicals released from the growth of fungus M. verrucaria have harmful effects, and act as a natural herbicide for reducing the overgrowth of Kudzu. The chemical is diacetylverrucarol. The use of this biological control method is effective because the other plants are not damaged. Other chemicals (artificial herbicides) are also sprayed on the Kudzu vines to limit their spread. These are picloram, glyphosate, and triclopyr.
3. Shading the kudzu for a longer period can cause a decline in the growth of vines. They are very sensitive to the amount of sunlight supplied. When one keeps these vines under shade and prevents them from getting direct sunlight for a longer duration, it might also prove fatal for kudzu.
4. The higher water content in the soil growing kudzu vines is also damaging to the roots of kudzu.

Problems caused by Kudzu

1. The chemicals of the kudzu plants can cause air pollution. Ozone is produced when the nitrogen in the air reacts with the nitric oxides and neoprene. The ozone at the lower levels of the troposphere acts as a pollutant damaging skin and eyes.
2. The invasive growth of Kudzu vines is damaging to higher plant families. Smothering has been discussed above. It has also decreased the economic growth related to higher plants.
3. The chemicals released by these vines are also responsible for zero photosynthesis when mixed with the freshwater bodies. Plant life inside freshwater bodies decreases due to the isoprene release.
4. When consumed by human beings it might damage their liver. The bugs called Kudzu bugs may cause skin infections when being exposed to them^[7]Li, Y., et al., Invasive ornamental plants: Problems, challenges, and molecular tools to neutralize their invasiveness. Critical Reviews in Plant Sciences, 2004. 23(5): p. 381-389. Read.

Uses of Kudzu

1. The deep root system prevents soil erosion
2. Its chemicals can be used in traditional medicines.
3. The vines can be used for ornamental purposes.
4. These vine plants cover the empty spaces very quickly.
5. Used to treat the after-effects of consumption of a large amount of alcohol.
6. It is used in the treatment of many diseases such as it can cure hangovers, low immunity, aches, stomach issues, and dizziness as well^[8]Wong, K.H., et al., Kudzu root: traditional uses and potential medicinal benefits in diabetes and cardiovascular diseases. Journal of Ethnopharmacology, 2011. 134(3): p. 584-607. Read.

Care of kudzu

1. There is not much care required for the kudzu vines, some of the important things are mentioned below:
2. The plant needs well-drained soil for better growth.
3. The plants need no chemical fertilizers as they might get damaged by the chemical interactions.
4. It is good to maintain a constant water table in the soil for better growth.
5. Proper trimming and cutting will keep a balanced growth and one can also give different shapes to it.
6. A moderate temperature is the best to thrive these vines^[9]Miller, J.H., Kudzu eradication and management. In: Hoots:, Diane; Baldwin, Juanitta, comps., eds. Kudzu the vine to love or hate. Kodak, TN: Suntop Press: 137-149., 1996. Read.