Nanocellulose is gaining evident interest from researchers and engineers because of its renewability, biocompatibility, biodegradability, high mechanical strength, abundant hydroxyl groups for potential functionality, and extensive raw materials. Versatile sources are accordingly explored like harvested wood, annual plants, and agricultural residues. However, an abundant shrub plant, Amorpha fruticosa Linn., has not yet been reported for isolating nanocellulose. We accordingly propose a green method with low energy consumption to extract nanocellulose from the vast shrub source via combined grinding and successive homogenization treatments. The derived nanocellulose possesses a fine structure with a diameter of ∼10 nm and an aspect ratio over 1000, high thermal stability with a maximum decomposition temperature of 337 °C, and similar composition with a hydroxyl group and a crystal I structure to that of natural cellulose. The demonstrated nanopaper presents visible light transmittance over 90% and haze below 15%, which further confirms the fine structure of the derived nanocellulose. Such a method could potentially broaden the major shrub plant with green, sustainable, up-scaled, and value-added applications in high-end domains like electronics, biomedicine, aerospace, energy, environments, etc.