Warfarin, the rat poison, is used to thin the blood of heart patients. It is vitally important that people don't go out and start drinking Roundup because they think it will be good for their health. Purple loosestrife, a beautiful garden plant with an aggressive nature, has been in North Dakota for at least 50 years as a cultivated flower. It's been shown that these garden varieties of purple loosestrife, once thought to be sterile, can cross breed with wild varieties. In the wild, purple loosestrife crowds out native plants and destroys habitat for ducks, muskrats and other wildlife.
Heavy infestations can reduce stream flow.
Even with infestations in or near Grand Forks, Fargo, Valley City and Minot, there is less than 50 acres of purple loosestrife in the entire state which makes it a very manageable infestation. In 1996, purple loosestrife was placed on the North Dakota noxious weed list which includes the weeds considered by North Dakota officials to pose the most serious economic or health threat. Purple loosestrife is the only weed on the list that does not pose a threat to the state's crops or rangeland. Purple loosestrife clogs thousands of acres of wetlands, lakes and waterways in Minnesota and other nearby states and provinces. It can spread when seeds float away and sprout or broken parts of the plant take root.