Madagascar periwinkle is a tolerant plant that can become established in a variety of tropical and subtropical habitats.  In Madagascar, the plant’s native home, it has been collected in open woods, shrublands, grasslands, and disturbed areas, along roadsides, and on beaches and limestone rocks.  It is found from sea level to 900 m altitude, on a variety of substrates. 

Reference

van Bergen, M. A. 1996. Revision of Catharanthus G. Don. Series of revisions of Apocynaceae XLI. Wageningen Agricultural University Papers 96-3: 9-46.