St. Andrew’s Cross[Hypericum hypericoides] photographed in the Vining yard on 9 July 2013 and 30 August 2020. It’s a member of the Mangosteen (Clusiaceae) family, genus St. Johnswort. Wildflowers of the Carolinas, pages 330-331, says it blooms in summer and fall and can be found in “dry to moist sandy or rocky soils, pinewoods, bogs.” There are many Dwarf Cinquefoil plants growing with these flowers.
USDA Plants Listing: Hypericum hypericoides