I found this plant growing in the middle of my sunny garden, along with my day lilies, balloon flowers, echinacea, etc. Common St. John's Wort (Hypericum perforatum) is so distinctive with the black dots along the edges of the flower petals. You will find this plant "along trails, roads, and in fields or open woods."Dwelley, Marilyn J. Summer & Fall Wildflowers of New England. Camden, Maine: Down East Books, 2004. Print.