Musk thistle is variable in its flowering strategy, acting as a biennial, a winter annual, or an annual. Plants typically overwinter as rosettes and send up flowering stalks the following spring. Flowering can occur from early June through October. Seeds mature and can begin dispersing within 7 to 10 days of flowering. As many as 11,000 seeds per plant may be produced.
Most seeds fall near the parent plant and can remain viable for as long as ten years.
Musk thistle infestations are economically important in agricultural systems because they compete with crops for light, space, nutrients, and water. The plants spiny tissue renders it unsuitable for livestock. As such, all landowners are required to control the plant if it is growing on their property. Control is considered to be prevention of seed production. County prosecuting attorneys are required to notify offending landowners in a prescribed manner before leveeing penalties.