In my experience, Vinca/Periwinkle vines really do best in either full sun or part shade, & in friable soil with a decent amount of organic matter. No extra fertilizing or any other attention necessary, except for extra watering while the plants are getting established. Without the first two requirements met, it will probably take quite a long time for your plants to really establish themselves, if they ever do.
As an example, I have some inherited Periwinkle planted beneath some mature White Pines when we bought our farm back in 1996. While the soil is beautiful, there's too much shade, so while the Periwinkle has survived & sporadically bloomed, the spread is still skimpy after all these years. Up by the house where it was planted in beautiful compost-enriched soil in full sun, it's almost become a weed that I have to pull at least once a season.
Culture/environment is everything.
My body is a temple. Unfortunately, it's a fixer-upper.