Flowers are produced in clusters at the upper portion of the stems in late summer. Individual flowers are greenish-yellow disk flowers. It has been grown as an ornamental and medicinal herb. Mugwort tolerates a wide range of soil conditions. Most infestations have resulted from vegetative introduction in nursery stock, topsoil, compost, or farm equipment.
Mugwort spreads by long, stout rhizomes.
Viable seed dispersal is important in the southeastern U.S., but rare in the Northeast. In the southeastern U.S., mugwort seeds are spread along streams by seasonal flooding. Mugwort is spread in field-grown nursery stock. Once introduced into landscapes, it can spread to turf areas and adjacent properties. Persistent rhizomes make mugwort difficult to control in perennial crops.