Catharanthus roseus, commonly known as Madagascar periwinkle, is a popular ornamental flowering plant native to Madagascar. It is a low-growing, herbaceous perennial with glossy green leaves and attractive, pinwheel-shaped flowers that can be pink, white, or lavender. Valued for its heat and drought tolerance, it is widely cultivated in gardens and landscapes around the world. Beyond its beauty, this plant is of significant medicinal importance; it produces valuable alkaloids like vinblastine and vincristine, which are used in chemotherapy to treat certain cancers.

Despite its benefits, Madagascar periwinkle poses a serious invasive risk in tropical and subtropical regions, including Hawaiʻi. It readily escapes cultivation, produces abundant seeds dispersed by wind and water, and can naturalize in disturbed areas, outcompeting native plants. It is reported as naturalized on multiple Hawaiian islands: Niʻihau (including Lehua), Kuaihelani (Midway Atoll), Kauaʻi, Oʻahu, Molokai, Maui, and Hawaiʻi. Once established, it can form persistent seed banks and is difficult to control. To protect Hawaiʻi’s native ecosystems, it is recommended to avoid planting this species and to remove it from natural areas where it appears.