INTEGRATED PEST MANAGEMENT PRESCRIPTION Canada thistle

Canada thistle (Cirsium arvense) is a perennial, which grows from 3 to 6 feet in height and has an extensive underground root system. Flowers are small, numerous and lavender to white in color. The flower heads grow on the tips of branches, male and female flowers are found on different plants, and both must be present to produce viable seeds. Viable seeds can remain dormant in the soil for up to 20 years. Leaves are long and narrow, deeply lobed with sharp, yellow spines on the edges. Canada thistle spreads by seed and aggressive, creeping, horizontal roots (rhizomes) that can extend 15 feet and vertical roots 6-15 feet deep. Nearly all parts of the root can produce buds that develop into shoots that grow and form new plants. Root segments as small as 1/8 to 3/8 inch in length and 1/16 inch in diameter can produce new plants. Impacts: Canada thistle is highly invasive. It can spread quickly to form dense patches, crowding out forage grasses by up to 60 percent. Canada thistle competes with crops