BACKGROUND: Native to southern Europe and western Asia, musk thistle thrives in pastures and rangelands, in waste areas, stream banks, and road sides.
DESCRIPTION: Musk thistle is a biennial or winter annual. Plants 4 to 6 feet tall are common. Deeply lobed spiny leaves are distinguished by a dark green blade with a prominent light green midrib. Stems are spiny and appear winged. Flowers may be violet, purple, or rose colored. Flowers are typically “nodding” or bent over. A tuft of white hairs is attached to each seed, which develops together at maturity and displaces the flowerhead. Bloom is in June and July.
CONTROL: Several biocontrol agents are available and offer good control. Herbicides can offer good to excellent control when applied between rosette and pre-bud stages. Mechanical means can be used for control by chopping the plant off at the ground.