Environmental Influences on Growth and Secondary Metabolite Accumulation in Eleutherococcus sessiliflorus Across Korean Cultivation Sites

<i>Eleutherococcus sessiliflorus</i> is a medicinal shrub widely used in East Asian traditional medicine, yet field-based studies on environmental influences remain limited. In this study, branches from 26 cultivation sites across South Korea were analyzed for relationships among growth traits, soil and climatic conditions, and two major compounds, chlorogenic acid (CGA) and eleutheroside E (EleuE). Growth traits varied widely, with plant height ranging from 1.06 to 4.20 m. CGA content was relatively stable across sites (0.292-0.708 mg/g), while EleuE showed greater variability (0.038-0.264 mg/g). The combined content of CGA and EleuE showed a weak positive correlation with thorn density (<i>r</i> = 0.236, <i>p</i> = 0.037). Plant height and basal diameter were positively correlated with temperature indices (annual average temperature <i>r</i> = 0.410, <i>p</i> < 0.001; annual maximum temperature <i>r</i> = 0.341, <i>p</i> = 0.002), whereas thorn density decreased with soil electrical conductivity, potassium, and magnesium but increased with sand and precipitation. Principal component analysis and correlation networks highlighted distinct clusters separating growth traits from EleuE-environment associations. These findings demonstrate that growth performance in <i>E. sessiliflorus</i> is strongly influenced by thermal regimes, while EleuE accumulation responds to soil texture and light availability, providing an empirical foundation for site-specific cultivation strategies and standardized quality management.