This study examined whether the field association between higher plant cadmium (Cd) accumulation and lower values of some quality traits in Artemisia selengensis represents a stable plant Cd-quality relationship. Twelve paired soil-plant samples were collected from a representative field setting covering four representative cultivar groups, consisting of one wild-source group and three cultivated types, across a soil pH gradient of 4.60-8.78. Plant Cd, crude fiber, soluble sugar, flavonoid components, and key soil physicochemical indicators were quantified and analyzed using effect-size comparisons and cultivar-adjusted residual correlations. Plant Cd was more closely associated with soil environment and showed a significant negative correlation with soil pH (r = -0.90, P < 0.01), whereas cultivar-group differences in plant Cd were not significant under the field sampling conditions of this study. By contrast, quality traits were mainly structured by cultivar background, with η² effect sizes of 0.87 for crude fiber and 0.96 for soluble sugar. After adjustment for cultivar background, the negative correlation between plant Cd and crude fiber weakened from r = -0.77 to r = -0.27, and correlations between plant Cd and several representative flavonoids also became non-significant, with no stable within-cultivar plant Cd-quality association retained. Within the medium-to-low soil total Cd range, four cultivar groups, and limited sample size of this study, this field pattern more likely reflects an apparent correlation caused by overlapping environmental heterogeneity and cultivar distribution, and is insufficient to support a stable inhibitory effect of plant Cd accumulation on quality formation.