Enhancing the removal of heavy metals from soil using plants is a promising technique. The key is to choose the right plants and additives. In this study, different additives were tested on metal-mobilizing capability and plant toxicity for Zn and Cd phytoextraction. Results showed that EDTA was effective for Zn and Cd mobilization, followed by a mix of additives. Acetic acid was toxic to plants at certain concentrations. Thlaspicaerulescens and S.alfredii were found to be good hyperaccumulators for Zn and Cd phytoextraction, respectively. Mixing additives significantly increased Cd phytoextraction. S.alfredii combined with a specific additive was particularly effective for Cd/Zn phytoextraction in polluted soils, reducing the risk of groundwater contamination.