Common groundsel is a winter annual member of the aster family. Groundsel has a taproot with a secondary fibrous root system. The sparsely hairy leaves are alternate on upright, many branched stems. The lower leaves are wavy margined to deeply lobed margins. Upper leaves are stemless and coarsely toothed to irregularly lobed. The flowers heads of common groundsel are composed of several yellow disk flowers. Common groundsel is a prolific seed producer. Seeds are produced within several weeks of groundsel germinating, resulting in several generations within the same year. Groundsel reproduces by seed. Groundsel is found throughout Canada and the United States and likes moist, rich soil.
Groundsel is most problematic in the autumn and spring during cool wet weather. Good drainage may help to discourage infestation. Dense healthy turf will prevent seeds from taking root. Heavy infestation will likely require post-emergent herbicide treatment in turf areas.
Make your post-emergence herbicide application to groundsel that is actively growing and in the seedling to flower stage of growth.