They do not persist in management systems that are severely disturbed seasonally. Biennials are most susceptible to herbicides when in the rosette stage. Many are held in check by close mowing. Mowing has the greatest impact when done just as the first flowers open. Bull thistle, musk thistle, and wild carrot are the most widespread problem biennials in Indiana.
Simple perennials survive best in perennial crops or undisturbed areas.
Those with leaves near the ground can survive mowing. Dandelion, plantains, curly dock and pokeweed cause the most problems. The herbaceous shoots flower, produce seed, and then die back, but the roots and crowns live several years. Creeping perennials reproduce by seeds and vegetative structures . They are capable of surviving in nearly all management systems.