Hypericum calycinum (Saint John's Wort)

Native from southeastern Bulgaria to northern and northwestern Turkey, this low perennial shrub spreads through underground stems. Oval to oblong leaves accompany large, five-petaled yellow flowers with a dense tuft of projecting stamens. It blooms in summer and is widely grown as a groundcover, particularly on slopes. It tolerates dry shade and some drought once established, although it flowers best in sun. Its vigorous spread can overwhelm smaller plants. It remains evergreen in mild climates but may die back and regrow after cold winters. It is poisonous if eaten. Photographed in Bogotá, Colombia.