Tree 8 - 12 m tall, trunk 40 cm - 0.9 m in diameter
Leaves: opposite or whorled, bright green above, paler beneath, 12 - 20 cm long, 10 - 12 cm wide, heart-shaped with a pointed tip, non-toothed or with few slight lobes, hairy beneath. Foliage releasing an unpleasant odor when crushed.
Flowers: borne on a pyramidal branched inflorescence (20 - 25 cm long), white with yellow and purple spots inside, 3 - 4 cm wide, petals fused into tubular or bell shape with three lower and two upper lobes.
Fruit: a cylindrical capsule, changing from green to brown, 15 - 40 cm long, 0.8 - 1.2 cm wide, persisting through winter, splitting into two and dropping in spring. Seeds are silvery gray, 2 - 3 cm long, and two-winged with fringed tips.
Bark: reddish brown with large, irregular scales.
Twigs: stout, greenish purple changing to reddish brown with thin ridges.
Leaf scars: almost circular.
Lateral buds: small, orangish brown, rounded. Terminal bud absent.
Similar species: Catalpa speciosa and Catalpa bignonioides are very similar. Catalpa speciosa has larger leaves, blooms about two weeks earlier, has fewer but larger flowers, furrowed bark, slightly wider pods, and lacks an unpleasant odor when leaves are crushed.
Flowering: May to June
Habitat and ecology: Sunny disturbed areas, fields, floodplains, along railroads and roadsides, dry upland sites and along streams.
Occurence in the Chicago region: non-native
Notes: The rot-resistant wood of this species is used for fence posts, railroad ties, cabinets, lumber, picture frames, and interior trim. Small branches tend to break during storms as the wood is brittle.
Etymology: Catalpa is the Native American name for this tree. Bignonioides means resembling Bignonia.
Author: The Morton Arboretum