Purple loosestrife is an exotic wetland perennial that invaded North America in the early 19th century. Native to Europe, this highly invasive plant was thought to have been introduced from the ballast of ships who used soil to weigh down the ships or by settlers to be used for their flower
gardens or as a medicinal herb.
Since its introduction to North America, it has become a serious invader of wetlands, roadsides and other disturbed areas. In 1992 the leaf eating beetles, Galerucella calmariensis were approved by Canadian and US governments for release to control the plant. The beetles are natural enemies and have shown to effectively reduce loosestrife populations by up to 85% and allow native
vegetation to become established.