Today I found several of these blooms in the shaded southwest corner of my goat-yard next door . . . the ground in that shaded corner is covered with this green vine . . . Jake and Mandy have not been in there to graze yet this year . . . I vaguely remember a green ground-cover that was there last year, but I never saw a bloom . . . and I definitely did not plant this . . . or anything else in that spot for that matter . . . anybody know what this is?
Edited the title from "Unidentified Bloom" to "Vinca aka Periwinkle" after proper identification was made by Carol (see below