Scotch thistle leaves are deeply lobed with long, stiff spines along the margins. The leaves have a winged appearance that continues down the stems of the plant. Fine hairs give the plant a grayish appearance. Purple flowers more than an inch in diameter are produced in the summer. Flower heads remain upright, rather than nodding as Musk thistle flowers do.
Stocks supporting the flowers are leafy.
Infestations of Scotch thistle often start in disturbed areas such as roadways, campsites, burned areas, and ditch banks. The weed adapts best to areas along rivers and streams, but can be a serious problem in pastures, grain fields, and range areas. Here in Weber County, this weed is a large problem in the cities of West Haven and Hooper, as well as un-incorporated western county areas such as Warren, Taylor and West Warren. The inserted photo shows the mature flower next to a bud. For a close up of this spectacular flower, either click here on on the small inserted flower.