Single-crystalline nanorods and nanowires are grown using a hydrothermal system with the assistance of polymer additives. Tetragonal perovskite PbZr0.52Ti0.48O3 nanorods (see Figure) are grown in the presence of poly(vinyl alcohol), while nanowires are formed in the presence of poly(vinyl alcohol) and poly(acrylic acid). The polymers are absorbed on the axial side of the particles, reducing the surface energy and inducing oriented growth.