Very tolerant of hot summers, Madagascar periwinkle is the southern and summertime replacement for true periwinkles. Its leaves may curl during hot, dry days, but they return to normal when temperatures drop and the dew falls in the evening. Features The true periwinkles, genus Vinca , are also in the Apocynaceae and quite similar to Madagascar periwinkle, but they do not perform as well in the heat. Madagascar periwinkle is the best choice for a southern bedding plant. Even in the north, Madagascar periwinkle is one of the most dependable summertime bedding plants for mass color.
Madagascar periwinkle contains a virtual cornucopia of toxic and useful alkaloids.
The plant has been used for centuries to treat diabetes, high blood pressure, asthma, constipation and menstrual problems. More recently, extracts from Madagascar periwinkle have been shown to be effective in the treatment of various kinds of leukemia, skin cancer, lymph cancer, breast cancer and Hodgkin's disease. Indeed, Madagascar periwinkle is a modern day success story in the search for naturally occurring anticancer drugs. It has caused poisoning in grazing animals. Even under a doctor's supervision for cancer treatment, products from Madagascar periwinkle produce undesirable side effects.