Canadian thistle

Description:

Mature leaves are spiny with deeply lobed leaves and several branching flower stalks. Leaves are alternate, oblong, or lanceolate, usually with crinkled edges and spiny-toothed margins that terminate in a spine. Leaves of the plant can be hairy or smooth. Canada thistle flowers can vary in color from pale blue to shades of purple with an occasional white ecotype. Variations in leaf and flower structures can be due to development of several ecotypes. Seeds of the plant are about 1/8 inch long, somewhat flattened, brownish, with a tuft of hair at the top.

Habitat:

Canada thistle can thrive in many environments but is most commonly found in relatively mesic areas. Canada thistle is occasionally found in dry habitats, such as sand dunes, but more often occurs in wet areas, such as stream banks, marshes, along ditches, and lake shores. Cultivated fields, pastures, roadsides, and disturbed areas, such as road or fence construction sites, are also areas where the plant can flourish.