Herrin, a simple and eco-friendly method for the synthesis of silver nanowires (Ag-NWs) has been reported. Silver nanowires were synthesized using Psidium guajava seed extract that acted as a reducing agent as well as a stabilizing agent for silver nitrate solution. Synthesis was carried out at 50 °C temperature under continuous UV-irradiation. Silver nanowires were initially characterized by a UV-visible and FTIR spectrophotometer. In addition, morphology and particle size of synthesized Ag-NWs were determined using Field Emission Scanning Electron Microscopy and X-ray diffraction (XRD) techniques. Nanowires were found to have 12.8 μm length and 200–500 nm diameter and cubic phase morphology. Furthermore, the catalytic potential of Ag-NWs for the degradation of methyl orange dye (MO) was determined. The selected dye was degraded successfully that confirmed the catalytic potential of Ag-NWs. The authors concluded that Ag-NWs can be synthesized using plant extract having excellent morphological features as well as impressive catalytic potential.