Why is Italian thistle a problem?
Italian thistle invades rangeland and pastures, reducing productivity by displacing desired grasses and interfering with available grazing areas.
Reproduction by seed creates dense stands resulting in deterred grazing and harm to livestock.
Controlling Italian thistle
Recognizing Italian thistle
Italian thistle is an annual or sometimes biennial that grows 6 to 8 feet tall with spiny, winged stems. Leaves are nearly hairless, green lobed and have cobwebby hairs on the undersides. Flowerheads are purple, narrow and in clusters of one to five. Bracts at the base of flowerheads are stiff and upright with hairs.
Italian thistle is most abundant in dry open areas such as rangelands and pastures forming dense stands and reproducing by seed. It germinates in the fall, overwinters as a rosette and produces flowering stalks in late spring.