Abstract <p>This study explores the synthesis of silver nanoparticles derived from <i>Hypericum perforatum</i> L. and their impact on peppermint growth and physiology, aiming to understand their mechanisms and potential in sustainable agriculture. Synthesis of silver nanoparticles via reaction with AgNO₃ at 37°C was done. The formation was confirmed by color change, UV-Vis analysis, dynamic light scattering (DLS), and scanning electron microscopy. A completely randomized design experiment with four replicates was carried out to examine the impact of different concentrations of silver nanoparticles (0, 10, 40, and 80 mg/L) on growth parameters and morpho-physiological characteristics of <i>Mentha piperita</i> L. The absorbance peak between 400–500 nm confirmed silver nanoparticle formation. The average particle size was 11.9 ± 0.7 nm, ranging from 11.2 to 12.6 nm, indicating a uniform size distribution, determined via DLS. At a concentration of 40 mg/L, these nanoparticles improved peppermint growth and reduced oxidative stress, evidenced by decreased levels of malondialdehyde and ion leakage, markers of oxidative damage and increased the chlorophyll <i>a</i> to chlorophyll <i>b</i> ratio. Conversely, at 80 mg/L, they failed to promote growth and exacerbated oxidative stress in peppermint. H₂O₂ content, SOD and catalase enzyme activity was induced at 80 mg/L concentration of <i>H. perforatum</i> silver nanoparticles. the results indicated low concentration of <i>H. perforatum</i> silver nanoparticles had positive effect on growth of peppermint and may enhance defense mechanisms for higher-level stress with important implications for interactions, and evolution future studies should investigate the bioactivity of <i>H.&#xa0;perforatum</i> silver nanoparticles and their potential applications in medical sciences, including comparisons with raw plant extracts.</p>