Greater periwinkle is native to the Mediterranean, but has naturalized in places such as British Columbia, milder areas of the United States and Australia. Despite its utility as a shady groundcover, it is not recommended for use in many areas due to invasiveness. The California Invasive Plant Council rates it as “moderate“, and this species also finds its way into the Global Invasive Species Database: Vinca major. This latter site provides this brief description of the species: “Vinca major is introduced to new locations usually as an ornamental or medicinal herb. It spreads locally from dumped garden waste, plant fragments carried downstream and as a garden escape along shady corridors. It grows most vigorously in moist shady areas in forests, along streams and urban areas. Once established the herb competes with native vegetation by smothering all native groundcover vegetation and preventing the regeneration of trees and shrubs. Vinca major is a serious threat to the understorey of forested areas and streamside vegetation.“
The Plants for a Future database provides a list of traditional medicinal uses. MissouriPlants.com has additional photographs and a description of the plant, as well as a brief argument for the use of scientific names: Vinca major.