Catalpa bignonioides is a tree to 15 m tall, branches widely spreading; bark gray, flaky, twigs stout, hairless, pith continuous, leaf scars opposite, broad, nearly circular, vein scars forming a ring inside leaf scars; winter buds.
Leaves opposite, often whorled at ends of twigs, stalk 8-16 cm; blade, 10-20 cm long, 7-20 cm wide, broadly egg to heart-shaped, finely hairy below, tip abruptly pointed, base blunt to slightly lobed, smooth above, finely hairy below, unpleasant odor when crushed, expanding in late May; winter plant leafless 184 days (Britton 1874).
Flowers white with 2 yellow stripes inside, densely purple-spotted, broadly tubular, bilaterally symmetrical, 3- 4 (5) cm wide across top, lower petal lobes entire, May-June; inflorescence 15-20 cm.
Fruit dry, hollow, linear, thin-walled 20-40 cm long, 0.6-0.8 cm wide, splitting open to release seeds, wings gradually narrowed at ends, with tuft of short hairs with tufts of hair at tips of wings, pods persistent on tree into winter.
Wetland status: UPL.
Frequency in New York City: Occasional.
Origin: Southern U.S. escaped from cultivation in north (Dirr 1990; Rehder 1986).
Habitat: Second growth, woodland, edges, fill, weedy, soil pH 5.5-7.5 (USDA, NRCS 2010).
Notes: Rather short lived 40-50 years (USDA, NRCS 2010). Much like C. speciosa but smaller and blooming about 2 weeks later (see below).