Aqueous extracts from leaves, stems, roots of the aromatic shrubArtemisia afraand soil on whichArtemisiawas grown, were used to investigate their inhibitory effects on germination and seedling development of maize (Zea mays), bean (Phaseolus vulgaris) and ryegrass (Lolium perenne). Dilutions of 1:1,1:2.5 and 1:5 v/v of the original extracts were prepared by adding deionised water to the original (undiluted) extracts. Deionised water and extracts from soil on whichA. afrahad never grown were used as controls. Extracts fromA. afrasoil and plant parts significantly (p < 0.05) reduced seed germination, height and dry matter of all the seedlings compared with the controls. However, as the dilution of the original extracts increased, there was a significant increase in seed germination and dry matter yields. This observation was consistent in all the plant species indicating that there was reduction in the concentration of the compounds inhibiting germination and seedling growth. The inhibitory effects on both seed germination and seedling development by the extracts was in the order leaves > stems = roots > soil. It was observed that germination was the process relatively more adversely affected by the inhibitory compounds in the extracts than growth of the seedlings. The results confirm that there are water-soluble compounds in the tissue of theA. afrashrub which can inhibit seed germination and growth of plant seedlings.