Hypericum is a genus of flowering plants that belong to the Hypericaceae family. There are many species of Hypericum, and some of them produce green flowers. One such species is Hypericum calycinum, a low-growing, evergreen shrub that has glossy, dark green leaves and produces bright yellow-green flowers in mid to late summer. The Hypericum Green flowers have five petals and are about 1 inch (2.5 cm) in diameter. In addition to its ornamental value, Hypericum calycinum has been used in traditional medicine to treat a variety of ailments, such as depression and anxiety.