Recycling sewage sludge (SS) as a soil amendment potentially causes soil heavy metals (HMs) contamination. This study investigated the potential roles of landscape plants co-planting in SS-amended soil remediation. Three landscape trees Mangifera persiciforma, Bischofia javanica, and Neolamarckia cadamba (NC), and three ground cover plants Dianella ensifolia, Syngonium podophyllum, and Schefflera odorata (SO) were selected for the tree-ground cover co-planting. Species in different co-planting treatments exhibited diversified effects on the growth, root morphology, HMs uptake, and HMs accumulation. Five plant characteristics including total root length, total surface of roots (diameter <2 mm), specific root length, shoot dry weight and root dry weight played crucial roles in plant HMs uptake. Structural equation modeling analysis revealed that different co-planting treatments drive species to develop an active, passive, or avoidance strategy to accumulate HMs, resulting in a diversity of HMs removal efficiency. Co-planting of NC with SO promoted NC and SO HMs accumulation and resulted in the greatest HMs contents decline (48.0% for Cd, 24.9% for Cu, 33.8% for Zn, and 27.2% for Ni) and the lowest potential ecological risk. Co-planting of landscape tree and ground cover plants with an active strategy can be a potential candidate for HMs phytoremediation of SS-amended soil.

回收污泥（SS）作为土壤改良剂可能会导致土壤重金属（HMs）污染。这项研究调查了在SS改良的土壤修复中联合种植园林植物的潜在作用。三棵风景树Mangifera persiciforma，Bischofia javanica和Neolamarckia cadamba（NC），以及三棵地被植物Dianella ensifolia，Syngonium podophyllum和Schefflera odorata（SO）被选择用于树地覆盖物的共同种植。不同共栽处理的物种对生长，根系形态，HMs吸收和HMs积累表现出多种影响。五个植物特征包括总根长，根总表面（直径<2 mm），比根长，枝干重和根干重在植物HMs吸收中起关键作用。结构方程模型分析表明，不同的共植处理会驱动物种发展主动，被动或避免策略来积累HM，从而导致多种HM去除效率。NC与SO的联合种植促进了NC和SO HM的积累，并导致最大的HMs含量下降（Cd为48.0％，Cu为24.9％，Zn为33.8％，Ni为27.2％），潜在生态风险最低。