A spiny biennial which produces a ground-level rosette the first year, and a tall spiny plant up to eight feet tall the second. The plant is a native of Eurasia and is now naturalized in many areas of the United States, including eastern Oregon. It is most often found along roadsides, irrigation ditches, waste areas and on rangelands, especially those adjacent to riparian or sub-irrigated deeper soils along stream courses, lower alluvial slopes and bottom lands. It often is found in dense stands which are impenetrable to livestock and people. Distribution -Prineville BLM District Presently found in most parts of district, but concentrated along the John Day River and Deschutes River canyons and side tributary canyons adjacent to riparian areas, ranging in a few scattered plants to dense areas of a few acres each.
Manual control is effective if in limited acreage or plant numbers.
Spring and fall applications of herbicide to rosettes, or spring application of herbicide to emerging stalks.