The accumulation and partitioning of the trace elements Cd, Cu, Mn and Zn was studied in yarrow plants (Achillea millefolium. agg., Asteraceae) grown in a pot experiment in the green house with and without additions of Cd, Zn or a combination of both metals to the substrate. Two soils were tested and the the plants were harvested four times during one year. As the Cd concentrations in the plants reached up to 10 mg.kg(-1) when the Cd supply in the soil was 3 mg.kg(-1), the yarrow can be characterised as a plant accumulating easily this heavy metal. The Cd accumulation in the plant was little influenced by a simultaneous addition of Zn: only in stems with flowers of the plants grown on a sandy soil a small reduction of the Cd contents could be observed. Zn had no influence on the Cd uptake. By the addition of Zn and Cd at once at the beginning of the experiment enhanced Cd and Zn levels were reached in the plants throughout all harvest times, indicating that Cd present in the soil will remain available to plants for a long time. Furthermore between the 3(rd) and 4(th) harvest, during an intensive growth period in early summer, a new mobilisation of Cd but not of Zn, Mn and Cu occurred from both soils, leading to enhanced Cd contents in the plants. The Cu and Mn contents in the plants were not influenced by the Cd and Zn additions to the soils.