We demonstrate a simple templateless and surfactant-free wet-chemical method of preparing silver (Ag) nanostructures with different dendritic morphologies at room temperature. This has been accomplished by aging the aqueous mixture of AgNO3 and citrate salts, carrying different cations for different time periods. Transmission electron microscopic (TEM) and X-ray diffraction (XRD) studies confirmed the formation of single-crystalline dendritic Ag nanostructures. It has been found that the nature and the concentration of citrate salt have a significant effect on the morphology of the formed Ag nanostructures. A possible formation mechanism has also been discussed on the basis of monitoring the surface plasmon resonance properties and TEM images with time during the course of formation of silver dendrites. The formed dendritic silver nanostructures showed excellent catalytic activity in the borohydride reduction of p-nitrophenol to p-aminophenol compared to the spherical silver nanoparticles.