There is two main Catalpa species that is native in North America. They are Northern Catalpa and Southern Catalpa. The Northern Catalpa (See Distribution Figure 8b), Southern Catalpa [See Distribution Figure 7a ((Click here to view Southern Catalpa Native habitat.)] and the Catalpa Ovata (See Figure 8c) could also be found in Southern Ontario and United States.[i] This species was introduced into North America from Asia. Catalpa generally consists of 11 main species; two are considered native to North America, 5 are in West Indies and 4 species are indigenous to China and Tibet.[ii] To see the distribution of the Catalpa Genus see Figure 8. In North America,  the Southern Catalpa is considered native to the South Eastern United States such as Mississippi, Louisiana and Florida and the Northern Catalpa originated from Midwestern United States such as Pennsylvania, Tennessee and Kentucky. It is also native to the flood plain forest from Southern Indiana to Arkansas.[iii] Despite the fact that the Northern Catalpa and the Southern Catalpa is considered native to North America, there is a mystery as to how the Catalpa evolved or where it originated from. Many researchers have suggested that the Catalpa might have truly originated somewhere south of North America and slowly made its way northwards after the glaciers in North America retreated.[iv] The Catalpa species did so by using their seeds inside their fruit by letting the wind carry them over oceans until it reaches North America.[v] As a result, the majority of researchers believed that the true origin of the Catalpa could be somewhere in the West Indies. It was believed that the Catalpa species made its way up to the United States   and established it as their habitat in Mississippi and Pennsylvania.[vi] The North American Catalpa species although first originated in the South Eastern and Midwestern United States was first documented by European explorers in North America. However, over 200 years since the European arrival the Catalpa genus has been extensively propagated into most parts, including the United States and to the extreme, the Rocky Mountains.[vii] It could now be found in many habitats in North America in coastal plains and bottomlands, forests, upland forests, mesics, floodplain forests, wet-mesics, wetlands, swamps, border of lakes, developed lands and restoration forests.[viii]

During the ice age most of North America especially Canada was covered in 2 Kilometer of ice.[ix] This is the reason why it is clear that the native origin of the Catalpa species is not native to Canada and United States. As research has shown that the Catalpa species is widely adaptable to a variety of climate it needs a minimum of 90 days without frost and cannot stand temperatures that are below minus 30 degrees Celsius.[x] This showed that these plants did not exist in North America during Ice age where all year round frost is. As a result, we can come to a conclusion that the Catalpa tree came to North America somewhere after the last glacial period which ended around 10,000 years ago. However, the arrival of the Catalpa tree, estimated date, in North America is still a mystery.[xi]

In many places in Ontario and the United States the Catalpa is distributed in cosmopolitan areas because these plants could be easily planted. As a result they are planted in many streets or park or people’s backyard.[xii] The reason they are used for these purposes by humans is because the Catalpa leaves have large leaves which is good for shades where the people can sit under these trees for shades.[xiii] Naturally the Catalpa uses the continuous distribution which was discussed earlier about the probability of seeds being distributed and carried of by wind and planted into a soil in another place.[xiv]

[i] United States Department of Agriculture: Natural Resources Conservation Service [Internet]. [updated 2008 October 11] United States: Department of Agriculture, Natural Resource Conservation Service; [cited 2008 October 26, 2008]. Available from http://plants.usda.gov/java/ClassificationServlet?source=profile&symbol=CATAL&display=31.

[ii]             . 1997. Catalpa Spp. [Internet] [Cited 2008, October 25] Available from. http://www.windsorplywood.com/nam_hardwoods/catalpa.html

[iii] Waldbauer G. 2003. What good are bugs?: Insects in the web of life. Cambridge. Harvard University Press. 82 – 86.

[iv] Sweeney S. 2005. Catalpa: Great American and invaders. The Monday Garden 162 (2): 40 –51.

[v] ________. Nature`s Hill Nursey. 2008. Southern Catalpa [Înternet] [Cited 2008, October 23, 2008] Available from. http://www.naturehills.com/product/southern_catalpa.aspx

[vi]            . 1997. Catalpa Spp. [Internet] [Cited 2008, October 25] Available from. http://www.windsorplywood.com/nam_hardwoods/catalpa.html.

[vii] United States Department of Agriculture: Natural Resources Conservation Service [Internet]. [updated 2008 October 11] United States: Department of Agriculture, Natural Resource Conservation Service; [cited 2008 October 26, 2008]. Available from http://plants.usda.gov/java/ClassificationServlet?source=profile&symbol=CATAL&display=31

[viii] Vines R. A. 2004. Trees, shrubs and woody vines of the southwest. Austin: University of Texas Press. P. 926-927.

[ix] Sweeney S. 2005. Catalpa: Great American and invaders. The Monday Garden 162 (2): 40 –51.

[x] ________. Nature`s Hill Nursey. 2008. Southern Catalpa [Înternet] [Cited 2008, October 23, 2008] Available from. http://www.naturehills.com/product/southern_catalpa.aspx

[xi] Sweeney S. 2005. Catalpa: Great American and invaders. The Monday Garden 162 (2): 40 –51.

[xii] Thone F. 1931. Nature Ramblings: Catalpa The Science News-Letter 19 (530): 366.

[xiii] Thone F. 1931. Nature Ramblings: Catalpa The Science News-Letter 19 (530): 366.

[xiv] Stephenson A G. 1980. Fruit set herbivores, fruit reduction and the fruit strategies of Catalpa Speciosa [Internet] [cited 2008 October 28] 61(1): 57-64. Available from: http://www.jstor.org/stable/pdfplus/1937155.pdf13.Catalpa Spp. [Internet] [Cited 2008 October 25]. Available from http://www.windsorplywood.com/nam_hardwoods/catalpa.html.