Native to China. Somewhat similar to catalpa in growth habit and leaves. Fast growth to 4050 feet., with nearly equal spread. Can grow 810 feet a year in youth. Often touted as miracle shade tree in advertising supplements. Heavy trunk and heavy, nearly horizontal branches. Foliage gives tropical effect: Light green, roughly heart- shaped leaves are 512 inches long, 47 inches wide. No significant fall color. Brown flower buds the size of small olives form in fall and persist through winter; they open before leaf-out in early spring, unfurling into 6- to 12 inches-long clusters of trumpet-shaped, 2 inches-long, fragrant flowers of lilac blue with darker spotting and yellow stripes on inside. Flowers are followed by 112- to 2 inches seed capsules shaped like tops; these remain on tree with flower buds. Does not bloom well where winters are very cold (buds freeze) or very mild (buds may drop off). Where it does bloom, numerous seedlings quickly invade disturbed areas such as highway banks, mining sites, and construction areas.
Performs best in deep, moist, well-drained soil, though it will grow in many soilsand even in cracks in the pavement. Tolerates air pollution. Protect from strong winds. Plant where falling flowers and leaves are not objectionable. Not a tree to garden under because of dense shade, surface roots. If tree is cut back annually or every other year, it will grow as billowy foliage mass with giant-size leaves up to 2 feet long; however, such pruning will reduce or eliminate flower production.
The wood is lightweight but strong, highly prized in Japan for making bowls, pots, spoons, furniture, and sandals. A mature tree commands a high market price. Unfortunately, this has led to tree rustling in the South. A happy tree owner retires at night, only to discover a stump the next morning.