We have lots of Vinca growing on the side of a little hill. I think a common name for this is Periwinkle. Here's a copy/paste of some info I posted last year from Wikipedia that talks about medicinal aspects of Vinca:
"There are at least 86 alkaloids extracted from plants in the Vinca genus. Vincristine, extracted from Vinca rosea Linn. (Catharanthus), is a type of chemotherapy called a vinca alkaloid used to treat some leukemias, lymphomas and childhood cancers, as well as several other types of cancer and some non-cancerous conditions. Vinblastine is a chemical analogue of Vincristine and also used to treat various forms of cancer."
This is beautiful, Anne! We always called these periwinkles when I was a child. My grandmother had a huge section of them. I never knew they had such medicinal properties.