The leaves of Catalpa speciosa are large and heart-shaped, simple and opposite or sometimes whorled. The flowers are very showy and numerous. The fruit (often perceived as a "pod") is a long, pendulus, cylindrical capsule that is usually at least 20 cm long and commonly over 30 cm long.

Catalpa speciosa is present in Wisconsin primarily as a cultivated tree, and rarely escapes near plantings in the southern counties. The map illustrates the area in which this species has been found to grow outside of cultivation. It may be expected as a yard tree much farther north.