Dotted loosestrife arrived in North American gardens as an ornamental import from Asia and southern Europe, and promptly made itself at home in ditches, meadows, and stream banks across the continent. Standing up to 3 feet tall in erect rhizomatous colonies, it produces cheerful yellow flowers with orange-red centers in whorled spikes that bloom with admirable persistence from late spring through fall. The whorled leaves are attractive in their own right, giving the plant a structured, almost architectural presence in the border.

It thrives in rich, moist, well-drained soils in full sun to part shade, and is most at home in wild gardens or naturalized areas where its spreading ambitions are not a problem. Growth slows noticeably in dry, shady conditions, which is a useful lever for those who want to temper its vigor near other plantings. Its Latin species name, punctata, means spotted, a nod to the fine dots visible on the flower petals.