Clermontia oblongifolia, commonly known as Oahu clermontia, is a perennial shrub or small tree native to the montane rainforests of the Hawaiian Islands, specifically on Oʻahu, Maui, and Molokaʻi. Subspecies ssp. oblongifolia is found in the moist, shaded environments of Oʻahu’s rainforests, while ssp. mauiensis, now extremely rare, is native to the wet montane forests of Maui. Subspecies brevipes, also endangered, is endemic to the high-elevation rainforests on Molokaʻi, with fewer than 30 plants remaining. Typically, Clermontia oblongifolia reaches heights of 3-5 meters, with a notable appearance characterized by large, oblong leaves and unique, curved flowers that are typically blue or purple and highly attractive to native Hawaiian birds. The flowering season spans several months, often from spring to early summer, with the flowers being quite showy and serving as a critical food source for nectar-feeding birds.

Oahu clermontia is valued for its unique flowers and its role in supporting native wildlife. It is used in habitat restoration projects and is sometimes cultivated in native plant gardens for its ornamental qualities and ecological significance. In cultivation, it requires conditions that mimic its natural habitat, including well-draining, fertile soil, consistent moisture, and partial to full shade. While not commonly found in the nursery trade, it is an important species for conservation efforts due to its limited numbers and habitat. Challenges in cultivation include vulnerability to non-native pests and diseases, as well as the need for protection from habitat destruction and invasive species.CC BY-SA 4.0