The species are shrubs to large trees ranging in size from 20 to 30 m (66 to 98 ft) tall. The leaves are bipinnate in most species, pinnate or simple in a few species. The flowers are produced in conspicuous large panicles, each flower with a five-lobed blue to purple-blue corolla; a few species have white flowers. The fruit is an oblong to oval flattened capsule containing numerous slender seeds. The genus differs from other genera in the Bignoniaceae in having a staminode that is longer than the stamens, tricolpate pollen, and a chromosome number of 18. This species thrives in full sun and sandy soils, which explains their abundance in warmer climates. Mature plants can survive in colder climates down to −7 °C (19 °F), however, they may not provide as full of blooms. Younger plants are more fragile and may not survive in colder climates when temperatures drop below freezing, so planting of younger trees in pots and moving them into a green house for winter is recommended.