Kudzu (Pueraria montana var. lobata) – Historical Profile

Written by: Brandon Holden, Alison Kilpatrick, Jonathan Sukhra, Lily Vuong

Canadian Kudzu population along the shores of Lake Erie
Canadian Kudzu population along the shores of Lake Erie near Leamington, Ontairo. Photo courtesy of Mike Cowbrough (Cowbrough, 2016).

HISTORICAL PROFILE

 The history of Kudzu, Pueraria montana var. lobata, started off in eastern Asia in primarily subtropical and temperate regions. The kudzu plant was introduced to the United States from Japan in 1876 at the Centennial Exposition in Philadelphia. The vine was widely marketed in the Southeast as an ornamental plant to be used to shade porches and later promoted as a forage crop (McGroarty, 2010). Concerns revolving around soil erosion through the 1930s and 1940s led the United States Department of Agriculture (USDA) to recommend the planting of Kudzu as a preventative measure along steep slopes throughout the south (Forseth & Innis, 2004). The Soil Erosion Service, a subsection of the USDA went on to provide approximately 85 million Kudzu seedlings to southern farmers, and paid them to plant the seedlings as a means to further prevent soil erosion throughout the Southern United States (Forseth & Innis, 2004; Grebner, Ezell, Prevost, & Gaddis, 2011). These activities were supplemented through a civilian corps movement that encouraged the planting of the vine in public lands and parks (Forseth & Innis, 2004). Due to governmental promotion, Kudzu had a solid hold throughout the Southeastern United States by the early 1950’s (Grebner et al., 2011). Even though Kudzu was removed from the list of permissible cover plants by 1953 (Grebner et al., 2011), declared a weed by 1970 (Hinman, 2011) and finally added to the noxious weeds list by 1997  (Grebner et al., 2011), the plant was able to spread throughout America and has made its way across the border into Canada. Kudzu is currently found on every continent with the exception of Antarctica (Gigon, Pron, & Buholzer, 2014 ).

In Canada, kudzu was discovered near Leamington, Ontario in 2009 and the population was estimated to be at least 8 years old at the time (Lindgren et al., 2013). It is not currently regulated as a pest under any legislation in Canada (Lindgren et al., 2013), nor does it have an official status as a noxious weed under the Weed Control Act (Waldron, 2012).

In  the United States, kudzu has been able to quickly grow over and shade other vegetation, causing damage to crops, orchards, and forest plantations. The greatest monetary impact of kudzu growth has been felt by the forestry industry where the productivity losses of entire young forest plantations have been estimated between $100 million and $500 million per year (Lindgren et al., 2013). There is also concern that kudzu can host soybean rust (Phakopsora pachyrhizi), and crop damage and yield losses have been a problem for farmers (Lindgren et al., 2013). In the United States, kudzu has damaged power lines which costs power companies an estimated $1.5 million per year (Lindgren et al., 2013). Kudzu has also reportedly grown over rail lines and caused derailments, costing railroad companies a significant amount in control costs (Lindgren et al., 2013). Costs of control in national and state parks are also reported to be considerable (Lindgren et al., 2013).

Using climate suitability models of current and future climate conditions, it has been predicted that changes in the global climate will allow for kudzu to spread northward (Lindgren et al., 2013). Waldron (2012) believes that it is likely that the kudzu population near Leamington, Ontario will spread further into southern Ontario unless measures are taken to control it.

ECOLOGICAL CONNECTIONS

 Kudzu is a specialized plant that will grow in certain conditions, thriving to r-strat_animal_yellowunmanageable states if presented ideal conditions, and if found in locations where survivorship is low, could take years for seeds to germinate (Lindgren, C. J. et al). Kudzu’s ability to rapidly grow and take over a deciduous forest canopy stand can surpass any healthy forest ecosystem’s tree growth. It is possible for the vine to have multiple canopy layers that can total the entire biomass of a deciduous forest canopy (Forseth & Innis, 2004).  Kudzu’s resilience to methods of eradication is strongly based on its large roots which store large amounts of starch, nitrogen, and water. The roots proficiency to grow into the substrate at 0.03 metres in depth a day, weighing over 180 kg and extending as deep as 3 metres is only one of many factors associated with the persistence of this plant (Forseth & Innis, 2004). This vine also has the ability to maneuver and redirect its leaf angles in relation to the direction of the sun; this is called paraheliotropism (Forseth & Innis, 2004). The leaves can be in positions to receive full sun, parallel to the sunrays to lower temperatures, and steep angles to prevent wilting (Lindgren et al., 2013). Kudzu’s adaptive qualities threaten local biodiversity through high competition for expanding room and below ground for roots. Studies have suggested that some of the common methods for controlling invasive vines, such as mowing, may be inadvertently causing the plants to grow back even more aggressively, which is something to consider when exploring management options (Kartzinel, Hamrick, Wang, Bowsher, Quigley, 2015). Kudzu is also a ‘structural parasite,’ meaning that, rather than supporting itself, it grows on top of other plants and buildings to reach light. Its ability to reproduce and spread quickly allows it to quickly cover shrubs, trees, and forests, where it blocks the sun’s rays from the plants below it, decreasing or eliminating their photosynthetic productivity (Miller & True, 1986).

CRITICAL ASSESSMENT OF MANAGEMENT OPTIONS

 The invasion of kudzu has proven to be costly to many industries in North America. With Kudzu being relatively new to Canada, and currently limited to a single outbreak, there is still a high probability that an effective management strategy can be implemented to control and eventually eradicate the vine from Canadian Shores. Some of the management options include doing nothing, grazing, chemical control, biological control, prescribed burning, and mechanical removal. These options are considered and assessed based on costs, benefits, and additional factors. Each option is explored in the following paragraphs and compared in Table 1.

There is the option to do nothing, however, seeing as kudzu is predicted to expand its range, this is not recommended. Kudzu will continue to be a burden on many industries if management of the species is not addressed. It may, however, be viable to focus efforts in controlling kudzu by utilizing it rather than removing it. One of these control measures is grazing by livestock. If heavily grazed on for 3-4 growing seasons, the root systems starve and this may effectively eliminate a kudzu population (Starr et al. 1999). However, vines can grow over fences and up trees, rendering them inaccessible to livestock (Lindgren et al., 2013).

A method used to manage kudzu populations is an herbicide called Glyphosate. In Mississippi, Glyphosate was used to tame kudzu and was successful in controlling 60-85% of the vine after 4 years (Lindgren et al., 2013). In some other states, regular use of Glyphosate with a backpack sprayer saw results of 80-100% success in just one season of use. Although herbicides have been effective against kudzu, it requires multiple and frequent applications (Minogue, Enloe, Osiecka, Lauer, 2011). Studies have shown that kudzu that has been controlled with herbicides, and shows no signs of growth, can emerge from its roots after a year, possibly more, of dormancy (Minogue et al., 2011). Some herbicide treatments have left the soil bare, making it difficult to reestablish native species, and does not halt the return of kudzu as it has no problem growing in disturbed areas (Minogue et al., 2011). In some cases, herbaceous species have been able to colonize areas where kudzu has been reduced chemically, however kudzu can return and overtop these species in a single growing season if the area is not closely monitored (Minogue et al., 2011).

Another form of control is prescribed burning. This process kills the foliage of the plant but also requires repeated applications to be effective (Starr, Martz, Loope, 1999).

There are several biological means that are already in place and more that may be implemented to control the growth of kudzu. Bacterial blights, insect herbivory, and insect seed predation occur in high levels in field populations of kudzu. Seed predation is quite prevalent, with up to 81% of seeds incurring damage in populations studied in North Carolina.  A study found two weevils that attacked the stems of kudzu and eight beetles that complete larval development in the kudzu roots. When evaluations of potential control agents are made, the range of the control agents must be considered. Efforts were made by the United States Forestry Service to find a biological control agent for kudzu. A “blackleg” fungus, a viral mosaic disease and a rust fungus have all been shown to cause mild injury to kudzu (Starr et al. 1999). Studies in China revealed that most of these biological control agents do not solely target kudzu, which is a risk to native species (Lindgren et al., 2013). More research needs to be done to determine the viability of biological control options.

Successful long term control of kudzu requires that the extensive root system be destroyed (Starr et al. 1999). As such, the mechanical removal of the entire root has proven to be effective in eradicating the species but is labour-intensive and time consuming (Starr et al. 1999). Another physical control method is close mowing but this requires frequent and repeated action (Starr et al. 1999). Close mowing has the same issues that grazing has as a control method because vines can grow up surfaces, which still requires alternative labour-intensive mechanical removal.

Table 1: Comparison of different potential management methods to deal with the invasive vine Kudzu. While time intensive, mechanical removal provides the greatest chance of success while reducing further negative impact on the environment.

Chart comparing the different Kudzu management method outlined above.

 

References

Cowbrough, Mike. (2016) Photo: Canadian Kudzu population, Lake Erie.

Forseth, I. N. Jr., & Innis, A. F. (2004). Kudzu (pueraria montana): History, physiology, and ecology combine to make a major ecosystem threat. Critical Reviews in Plant Sciences. 23(5):401-413

Gigon, A., Pron, S., & Buholzer, S. (2014). Ecology and distribution of the Southeast Asian

invasive liana Kudzu, Pueraria lobata (Fabaceae), in Southern Switzerland. EPPP Bulletin, 44(3), 490-501. Doi: 10.1111/epp.12171

Grebner, D. L., Ezell, A. W., Prevost, J. D., & Gaddis, D. A. (2011). Kudzu control and impact on monetary returns to non-industrial private forest landowners in Mississippi. Journal Of Sustainable Forestry, 30(3), 204-223. doi:10.1080/10549811.2011.530559

Hinman, K. (2011). Kudzu: how a wonder vine unveiled by Japan at the 1876 centennial began    eating America. American History, (2), 38.

Kartzinel, T. R., Hamrick, J. L., Chongyun, W., Bowsher, A. W., & Quigley, B. P. (2015).          Heterogeneity of clonal patterns among patches of kudzu, pueraria montana var. lobata, an invasive plant. Annals Of Botany, 116(5), 739-750. doi:10.1093/aob/mcv117

Lindgren, C. J., Castro, K.L., Coiner, H. A., Nurse, R. E., & Darbyshire, S. J. (2013). The biology of invasive alien plants in Canada (12): Pueraria montana var. lobata (Willd.) Sanjappa & Predeep. Canadian Journal of Plant Science. 93:71-95, doi:10.4141/cjps2012-128

McGroarty, M. J. (2010). How to control kudzu, the vine that ate the South. Kudzu’’ Retrieved from: http://www.freeplants.com/kudzu.html

Miller, J. H., & True, R. E. (1986). Herbicide tests for kudzu eradication. Georgia Forest Research Paper. Retrieved from https://www.srs.fs.usda.gov/pubs/misc/rp_gf065.pdf

Minogue, P. J., Enloe, S. F., Osiecka, A., & Lauer, D. K. (2011). Comparison of aminocyclopyrachlor to common herbicides for kudzu (pueraria montana) management. Invasive Plant Science and Management. 4:419-426

Starr, F., Martz, K., Loope, L. (1999). Kudzu (pueraria lobata): An alien plant report. United States Geological Survey Resources Division. Retrieved from http://www.hear.org/species/reports/puelob_fskm_awwa_report.pdf

Waldron, G. E., & Larson, B. M. H. (2012). Kudzu vine, pueraria montana, adventive in Southern Ontario. Canadian Field-Naturalist. 162(1):31-33

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Kudzu (Pueraria montana var. lobata) – Management Plan

Written by:  Brandon Holden, Alison Kilpatrick, Jonathan Sukhra, Lily Vuong

IMG_20160705_110452
Canadian Kudzu population along the shores of Lake Erie near Leamington, Ontario. Photo courtesy of Mike Cowbrough (Cowbrough, 2016)

Management Plan

This plan provides details regarding the integrated management plan to eradicate Kudzu from Leamington Ontario. Due to the isolated nature of the kudzu population in Ontario, the recommended management strategy is prescribed burning followed by physical/mechanical removal. This method is labour-intensive and time consuming but can effectively eradicate the species from the province and, therefore, the country. At the Leamington site, kudzu has formed a blanket that extends 31 metres from the beach to the top of a steep south-facing bank, and has reportedly spread along 113 metres of the shoreline, covering roughly 0.35 hectares of land (Waldron, 2012; Lindgren et al., 2013).As the longevity of Kudzu seeds in the soil is unknown (Lindgren, 2010), this management strategy is to be repeated yearly until Kudzu has been eradicated from the site. Following eradication, yearly surveys of the site and surrounding area should be conducted to ensure Kudzu does not  re-establish.

The combination of both management strategies is required to tackle the Kudzu population at Leamington as each on their own would be insufficient or too costly/labour intensive. Prescribed burns are effective at reducing the aboveground biomass, but cannot destroy Kudzu root nodes or crowns (Lindgren, 2010). If the root nodes/crowns are allowed to remain, Kudzu can re-establish.

Mechanical removal of Kudzu, while labour and time intensive, has been shown to be effective at removing Kudzu. Challenges with this method come with large populations where the level of labour required would be prohibitive. Due to the Leamington population being relatively small, addressing Kudzu with mechanical removal would be feasible.

It is the combination of both management strategies that allow this management strategy to be successful. Burning the above ground biomass lessens the amount of work required for mechanical removal, and allows for easier access to the root nodes and crowns. These would have to be removed with hand tools such as shovels, axes and hand clippers as the terrain at Leamington doesn’t allow for heavy equipment.

This management strategy should be implemented once per season, during the summer, after Kudzu has dedicated energy to growing leaves and shoots but before seed pods are established. A secondary burn could be implemented later in the season (fall) to destroy any regrowth following the first burn/mechanical removal. This reduces the remaining energy available to the roots to re-establish the following year.

As kudzu may have originally been planted intentionally at the Leamington site to stabilize the bank, it may be necessary to establish a plan to plant native riparian vegetation to prevent the bank from eroding after kudzu has been removed.

Legal Factors

With the proposed management plan, there are a number of legal factors that need to be taken into consideration. Kudzu is not listed on the Ontario Invasive Species Act and so there are no restrictions or prohibitions with respect to transport, possession or propagation of the plant. The management plan does not rely on pesticides in any form so no considerations need to be made in regards to the Pesticide Act. In Ontario, prescribed burns need prior approval from the Ministry of Natural Resources and Forestry (Ontario, 2016). After approval there are still a number of controls must be in place for the protection of private property and the public. There have to be licenced and qualified staff on site, everyone must be briefed as to their responsibilities during the burn, and communication between all parties must be maintained throughout the burn (Ontario, 2016 ).

Potential Challenges and Solutions

The biggest challenge to this management strategy is to ensure timely removal of Kudzu. The plan is designed to quickly destroy the current plants as well as promote seed bank germination in order to deplete it in a timely manner. To this end, ensuring removal of all root nodes and crowns is essential in order to reduce regrowth in subsequent years of the management plan. To ensure this happens, the mechanical removal portion of the management plan must be carried out in a thorough and comprehensive manner.

Conclusions

While Kudzu control can be a significant challenge in some areas, the Canadian population of the plant is small and isolated. The Kudzu population in Leamington represents a unique opportunity to eradicate the entire known population of the invasive plant from Canadian shores. As eradication is currently a viable option, every effort should be made while this holds true. The combination of prescribed burns followed by mechanical removal of root nodes and crowns provides the greatest chance at successful removal of Kudzu while limiting cost and chance of greater environmental degradation. The undetermined nature of kudzu’s introduction into Ontario makes it difficult to design an effective plan to prevent the reinvasion of the species in the future. The likelihood that it was introduced through intentional planting would mean that the only necessary action for the prevention of reinvasion would be to not consider the species for bank stabilization in the future

References:

Alderman, D. H. (2015). When an exotic becomes native taming, naming, and kudzu as regional symbolic capital. Southeastern Geographer, (1), 32.

Boersma, P. D., Reichard, S. H., & N., V. B. (2006). Invasive species in the Pacific Northwest.   Seattle, WA: University of Washington Press.

Bergmann, C., Swearingen J, M. (2009). Plant Conservation Alliance’s Alien Plant Working       Group: Kudzu. Retrieved from: https://www.nps.gov/plants/alien/fact/pumo1.htm

EDDMapS. 2017. Early Detection & Distribution Mapping System. The University of Georgia – Center for Invasive Species and Ecosystem Health. Available online at          http://www.eddmaps.org/; last accessed January 27, 2017.

Forseth Jr., I. N., & Innis, A. F. (2004). Kudzu (Pueraria montana): History, Physiology, and     Ecology Combine to Make a Major Ecosystem Threat. Critical Reviews In Plant    Sciences, 23(5), 401. doi:10.1080/073526804905150

Frye, M. PhD. (2010) Lessons Learned from Six Years of Kudzu Research. Cornell University.    Retrieved from: https://nysipm.cornell.edu/sites/nysipm.cornell.edu/files/shared/documents/kudzu.pdf

Gigon, A., Pron, S., & Buholzer, S. (2014). Ecology and distribution of the Southeast Asian      invasive liana Kudzu, Pueraria lobata (Fabaceae), in Southern Switzerland. EPPO   Bulletin, (3), 490. doi:10.1111/epp.12172

Grebner, D. L., Ezell, A. W., Prevost, J. D., & Gaddis, D. A. (2011). Kudzu Control and Impact on Monetary Returns to Non-Industrial Private Forest Landowners in Mississippi.        Journal Of Sustainable Forestry, 30(3), 204-223. doi:10.1080/10549811.2011.530559

Hinman, K. (2011). Kudzu: how a wonder vine unveiled by Japan at the 1876 centennial began    eating America. American History, (2), 38.

(2009, September 23). Invasive Plant Species Takes Root in Canada. CBC News Windsor.         Retrieved from http://www.cbc.ca

Kartzinel, T. R., Hamrick, J. L., Chongyun, W., Bowsher, A. W., & Quigley, B. P. (2015).          Heterogeneity of clonal patterns among patches of kudzu, Pueraria montana var. lobata,    an invasive plant. Annals Of Botany, 116(5), 739-750. doi:10.1093/aob/mcv117

Kudzu. (2014). Kudzu (Pueraria montana). Retrieved from: www.ontario.ca/document/kudzu

Lindgren, C. J., Castro, K. L., Coiner, H. A., Nurse, R. E., & Darbyshire, S. J. (2013). The         Biology of Invasive Alien Plants in Canada. 12. Pueraria montana var. lobata (Willd.) Sanjappa & Predeep. Canadian Journal Of Plant Science, 93(1), 71-95.       doi:10.4141/CJPS2012-128

Minogue, P. J., Enloe, S. F., Osiecka, A., & Lauer, D. K. (2011). Comparison of    Aminocyclopyrachlor to Common Herbicides for Kudzu (Pueraria montana) Management. Invasive Plant Science & Management, 4(4), 419-426. doi:10.1614/IPSM- D-11-00024.1

(2016, December 9). Prescribed Burns. Retrieved from https://www.ontario.ca/page/prescribed-         burn#section-2

Rashid, H., Asaeda, T., & Uddin, N. (2010). The Allelopathic Potential of Kudzu (Pueraria       montana). Weed Science, 58(1), 47-55. doi:10.1614/WS-09-106.1

Smith, A. L., Hewitt, N., Klenk, N., Bazely, D. R., Yan, N., Wood, S., & … Lipsig-Mummé, C.   (2012). Effects of climate change on the distribution of invasive alien species in Canada:   a knowledge synthesis of range change projections in a warming world. Environmental        Reviews, 20(1), 1-16.

USDA Forest Service. (2004) Kudzu Pueraria montana. Retrieved from:          www.na.fs.fed.us/spfo/invasiveplants/factsheets/kudzu

Wong, K. H., Li, G. Q., Li, K. M., Razmovski-Naumovski, V., & Chan, K. (2011). Review:      Kudzu root: Traditional uses and potential medicinal benefits in diabetes and cardiovascular diseases. Journal Of Ethnopharmacology, 134584-607. doi:10.1016/j.jep.2011.02.001
Yang, X., Huang, W., Tian, B., & Ding, J. (2014). Differences in growth and herbivory damage   of native and invasive kudzu (Peuraria montana var. lobata) populations grown in the        native range. Plant Ecology, (3), 339. doi:10.1007/s11258-014-0304-4

Kudzu (Pueraria montana var. lobata) – Ecological Profile

Written by: Alison Kilpatrick

Distribution: Kudzu (Pueraria montana var. lobata) is a perennial vine native to China, Korea, Japan, India and eastward through the Philippines (Lindgren, Castro, Coiner, Nurse, & Darbyshire, 2013). Populations of Kudzu have been noted outside of its native range in Australia, New Zealand, Italy, Switzerland, South Africa, South America, Mexico, the United States, and now Canada (Pasiecznik, 2007). Kudzu was introduced into the United States in Pennsylvania and was widely encouraged to be planted by landowners (Forseth & Innis, 2004). It has since naturalized and spread west to Texas, east to Massachusetts, north to Michigan, and south to Florida (Lindgren et al., 2013). There have also been reports of Kudzu on the west coast in Washington and Oregon (Lindgren et al., 2013). Kudzu now covers approximately 3 million hectares of land in the United States and is estimated to be spreading by 50,000 hectares per year (Forseth & Innis, 2004).

Kudzu_World

Figure 1: Current global distribution of Kudzu, Pueraria montana (Base map: ESRI 2015; Distribution modified from EDDMaps)

Kudzu_Leamington

Figure 2: Kudzu range within Canada. Kudzu is currently limited to one small population on the shores of Lake Erie near Leamington, Ontario (Base map: ESRI 2015; Distribution modified from EDDMaps).

Habitat: Kudzu’s ability to establish itself in a wide range of conditions makes it a generalist species. It can be found in a wide variety of habitats including forests, shores, floodplains, fields, and disturbed areas (Lindgren et al., 2013). While it thrives in areas that are open and have well-drained, fertile soils, it can establish itself in nutrient-deficient soils due to its ability to fix nitrogen from  the atmosphere (Lindgren et al., 2013). Kudzu does not grow well in soils that are shallow or poorly-drained (Lindgren et al., 2013). It can grow in soils ranging from acidic (pH 4.5) to neutral (pH 7.0), but it does not do well in soils that have a high pH (Lindgren et al., 2013). Kudzu is most productive when it has access to full sunlight (Lindgren et al., 2013). It is sensitive to cold, so it is most successful in locations that have mild winters (mean temperature between 5-15°C) and hot summers (mean temperature over 25°C), but its roots are reportedly capable of surviving temperatures as low as -25°C (Lindgren et al., 2013).  For optimal growth, Kudzu requires at least 100 cm of precipitation annually, however the mean annual precipitation in the Leamington area is only 93 cm (Lindgren et al., 2013). This population is currently growing on a clay-rich slope on the shoreline of Lake Erie, where the mean temperature in January is -4.6°C and in July it is 22.3°C (Lindgren et al., 2013).

Potential For Infestation: Kudzu exhibits characteristics of r-strategists. r-strat_animal_yellowIt is a
perennial that can grow in unstable conditions, allocates little energy
into seed production but produces many seeds multiple times, and its seeds have a low probability of surviving the early stage of life (Lindgren et al., 2013). See Table 1 for the summary of Kudzu characteristics that support its classification as an r-strategist.

Table 1: Summary of the reproductive characteristics of Kudzu compared to those of K and r-selected species (Molles & Cahill, 2014; Forseth & Innis, 2004). Kudzu aligns best with the reproductive characteristics of r-strategists.

Characteristic K-strategist r-strategist Kudzu
Environment Stable Unstable Capable of establishing in disturbed areas
Mortality Higher probability of surviving to adulthood Lower probability of surviving to adulthood Most seeds do not establish as seedlings
Size Large bodied Small bodied Relatively small herbaceous vine
Fecundity Few offspring at a time Many offspring at a time Produces many seeds at a time
Frequency of Reproduction Multiple times over a prolonged period Once to multiple times over a short period Produces seeds every season
Energy allocation Higher energy allocated to producing offspring Lower energy allocated to producing offspring Low energy allocated to seed production, high energy allocated to extension growth

Survivorship: Kudzu  follows the Type III survivorship curve typical of plants (see Figure 3). Its seeds usually do not successfully establish (Lindgren et al., 2013). Therefore, this species has a low probability of survival in its early stage of life. Once established, Kudzu continues to grow through vegetative reproduction (Lindgren et al., 2013).

survivorship-curve

Figure 3: Survivorship curves (Image credit: Husthwaite, n.d.)

Dispersal and Vectors: Kudzu produces seeds annually and its seed pods can disperseVector_Human
up to 25 meters but most stay within 6 meters of their origin (Lindgren et al., 2013). However, despite the production of viable seeds, Kudzu seedlings are rare and usually do not survive to the following year when found in the wild (Lindgren et al., 2013). This suggests that seeds are not effectively dispersed or that there is something preventing seedlings from establishing (Lindgren et al., 2013). Therefore, the principal method of propagation of Kudzu is vegetative reproduction rather than sexual reproduction
(Lindgren et al., 2013). It spreads through rapid extension growth and frequent rooting of stems that contact the soil (Forseth & Innis, 2004). Humans are a primary vector for Kudzu dispersal as most long-distance dispersal has been through intentional planting by humans (Forseth & Innis, 2004). Kudzu’s method of introduction into Ontario is currently undetermined, though several possibilities have been considered including water dispersal across Lake Erie, bird dispersal, disposal of farming materials, or intentional planting for stabilization of the shore (Lindgren et al., 2013). However, there is insufficient evidence to support any of these methods as the source for the population in the Leamington area (Lindgren et al., 2013).
Special Considerations: Kudzu is an aggressive competitor because its rapid growth rate allows it to smother and shade other species before they can establish (Forseth & Innis, 2004). In addition, a compound that inhibits seed germination and plant growth has been found in Kudzu root and leaf extracts (Lindgren et al., 2013). High concentrations of this compound found in soil following Kudzu decomposition could be enough to result in allelopathic effects on some plant species (Lindgren et al., 2013). Through its ability to fix nitrogen in the atmosphere, Kudzu can alter an ecosystem’s nitrogen cycles and can potentially affect regional air quality (Forseth & Innis, 2004; Lindgren et al., 2013).

References:

EDDMapS (2017). Kudzu: Pueraria montana var. lobata (Willd.) Maesen & S. Almeida. Early Detection & Distribution Mapping System. The University of Georgia – Center for Invasive Species and Ecosystem Health. Retrieved January 26, 2017 from https://www.eddmaps.org/distribution/viewmap.cfm?sub=2425

Forseth, I. N, Jr. & Innis, A. F. (2004). Kudzu (pueraria montana): History, physiology, and ecology combine to make a major ecosystem threat. Critical Reviews in Plant Sciences. 23(5):401-413.

Husthwaite, R. (n.d.). Survivorship curves [image]. Retrieved January 26, 2017 from https://en.wikipedia.org/wiki/Survivorship_curve

Lindgren, C. J., Castro, K.L., Coiner, H. A., Nurse, R. E., & Darbyshire, S. J. (2013). The biology of invasive alien plants in Canada (12): Pueraria montana var. lobata (Willd.) Sanjappa & Predeep. Canadian Journal of Plant Science. 93:71-95, doi:10.4141/cjps2012-128

Molles, M., & Cahill, J. (2014). Ecology: concepts and applications (3 edition). New York: McGraw-Hill.

Pasiecznik, N. (2007). Pueraria montana var. lobata (kudzu). Invasive Species Compendium. Retrieved January 26, 2017 from http://www.cabi.org/isc/datasheet/45903