Noxious weeds

Noxious weeds are designated plants by state or national agricultural authorities as plants that are injurious to agricultural and/or horticultural crops and or humans and livestock. Most have been introduced into a foreign ecosystem either by accident or mismanagement, but some are also native species. Typically they are plants that are aggressive growing and/or multiply quickly and adversely affect desired plants or somehow are injurious to livestock or humans ether by contact or when ingested. They are presently a large problem in the western United States, greatly effecting areas of agriculture, forest management and other open lands.