Similar to Paulownia tomentosa (Thunb.) Sieb. & Zucc. ex Steud.
Cigar Tree or Northern Catalpa, Catalpa speciosa, a native tree, resembles Paulownia in size, leaf and flower structure. Notable differences are found in pith, leaves, and seed pods. Princess tree has a hollowed or chambered pith, while that of the catalpa is solid and whitish. Catalpa leaves are whorled and more distinctly pointed at the tip than Paulownia leaves, which are not whorled and have a less elongated tip. Catalpa fruits are long, slender pods measuring 8-18 inches (20-46 cm). Fruits of the princess tree measure only 1.5 inches (3-8 mm) and appear in clusters of round capsules. Catalpa flowers have a two-lipped calyx and appear on the current year's growth; princess tree has a five-lobed calyx and flowers on the second year's growth.
A related native tree, Southern Catalpa Catalpa bignonioides, is similar to the northern species.