Catalpa speciosa (Northern Catalpa) grows into a loose oval shape, 50 feet tall in most urban locations, but occasionally grows to 90 feet under optimum conditions. This large-leaved tree spreads 50 feet and tolerates hot, dry weather, but leaves may scorch and some drop from the tree in very dry summers. The leaves of speciosa are opposite.
Catalpa bignonioides (Southern Catalpa) is somewhat smaller, reaching only about 30 to 40 feet tall, leaves are arranged opposite or in whorls and a southern U.S. native. A sunny exposure and a well-drained, moist, rich soil is preferred for best growth of Catalpa but the tree will tolerate a range of soils from acid to calcareous. It is sometimes called the Indian bean tree.
Both trees have a coarse, very open growth habit forming an irregularly shaped crown. Catalpa has a moderately-long life (60 years or so), but trunks on large trees often contain rot. Catalpas are very adaptable and they are tough trees, having naturalized in many parts of the south.