USDA Plant Database
Atlas of Florida Vascular Plants
Oregon State University
Catalpa bignonioides is a native of North America, originally distributed within Florida, Alabama, Georgia and Mississippi. It has since naturalized throughout the country from ornamental plantings. Within Utah this species is established in Grand, Washington, and Utah counties at or below 1750m1.
C. bignonioides may attribute its success outside of its original range due to allelopathy and its tolerance to a wide range of water availabilities. By allelopathy, this species produces certain chemicals that adversely affect the growth of other plants, including members of the same species. Because of this apparent competitive advantage and non-native status throughout much of its current range, C. bignonioides is considered to be an invasive weed by some organizations. However, it is suggested for planting in Utah due to its medium drought tolerance, which it achieves by dropping its leaves.
This plant has a number of traditional medical uses including use as a laxative, sedative, and antiseptic. In southern states the tree is utilized to produce catalpa sphinx moth caterpillars (Ceratomia catalpae) for use as fishing bait. Large-scale caterpillar production has been attempted but tends to fail due to allelopathy and the difficulty of maintaining healthy populations of both pests and hosts. C. bignonioides reduces herbivory from the caterpillars by producing extrafloral nectar to attract ants for protection.
Non-web references:
1. Welsh, S. L., Atwood, N. D., Goodrich, S. and Higgins, L. C., 2003: A Utah Flora. Third edition. Brigham Young University Press. Provo, Utah. 912 pp