Native to a narrow band of the central United States — from Indiana and Illinois south into Tennessee and Arkansas — Northern Catalpa long ago made its way across the continent as a beloved, if slightly disreputable, shade tree. It grows fast and grows large, reaching 40 to 70 feet, with a broad crown carried on a short, thick trunk and branches that seem to extend in every direction at once. In late spring to early summer the flowers arrive in upright panicles, each individual bloom a wide-mouthed white trumpet streaked inside with bright yellow and spotted with purple. The show is brief but memorable, and the long green seed pods that follow are ornamental in their own theatrical way, darkening through summer and persisting through winter.

The foliage is among the largest of any hardy tree — broad, heart-shaped leaves that emerge with a fresh green smell entirely unlike the fetid odor of its southern cousin, Catalpa bignonioides. In autumn they turn yellow, then a distinctive sooty black before falling. For gardeners in zones 4 through 8, Northern Catalpa earns its place in difficult spots: wet low areas, compacted soils, dry banks where other trees refuse to settle. It is also a keystone host for the catalpa sphinx moth (Ceratomia catalpae), whose larvae feed on the foliage and in turn become critical food for nesting birds and foraging bats — a reminder that a tree's value in the garden is rarely just about flowers.