Leafy spurge infestation covering an entire hillside on part of a National Wildlife Refuge in Minnesota.

Leafy spurge is an exotic perennial forb native to the continents of Europe and Asia that was introduced into North America in the early 1800s. Most reports indicate that introductions first occurred in the eastern seaboard states through contaminated grains.

By the late 1800's and early Twentieth Century, leafy spurge spread to the vast expanses of grasslands throughout the upper Great Plains via westward expansion of Euro-American settlers. Since its introduction, leafy spurge established quickly and created large monocultures that reduced the forage quality of grasslands for livestock production and lessened the biological diversity of many North American grassland ecosystems.

Today, leafy spurge is estimated to occupy 2.5 - 3 million acres of land throughout North America. Controlling leafy spurge is expensive. In the United States, millions of dollars of direct landowner costs, in addition to taxpayer dollars, were spent annually over the last 60+ years trying to manage this highly invasive weed.

Like most invasive plants, leafy spurge has a series of characteristics that allow it to aggressively compete with native plant communities and to survive chemical, cultural, and mechanical controls, thus allowing it to eventually dominate the plantscape.

Furthermore, it is toxic to most native and domesticated grazing animals and is documented to cause irritation to the mouth and digestive tract of cattle and horses. These species avoid feeding in or near leafy spurge infestations. This creates a fundamental problem for habitat managers and livestock producers throughout leafy spurge's introduced range. As the amount of spurge increases, the amount of high quality forage for grazing animals and the amount of quality habitat for indigenous plant and animal species decreases.