Four 14C-labeled herbicide solutions were used to determine uptake and translocation patterns in mugwort (Artemisia vulgaris L.) roots. The 14C-(2,3,6-trichlorophenyl)acetic acid (14C-fenac) was bound in the roots and rhizomes and structures initiated on the rhizomes were heavily labeled. Little movement of 14C-isomers of fenac or 14C-fenac occurred from point of application on leaves. Rhizomes devoid of roots did not offer an appreciable avenue for entry of 2-chloro-4,6-bis-(ethylamino)-s-triazine (14C-simazine) into mugwort. Little movement of 3-amino-s-triazole (14C-amitrole) occurred from primary to secondary plants. Uptake of 14C-fenac was not increased appreciably by pretreatment of the plant root-rhizome system with (2,4-dichlorophenoxy)acetic acid (2,4-D), 2,4-dinitrophenol (DNP), or simazine.