We demonstrate a simple method to direct the self-assembly of ZnO nanorods on flat and curved surfaces in hydrothermal synthesis by precoating the substrate with a thin film of aluminum (Al). The Al was transformed in the alkali hydrothermal environment into hydrotalcite-like zinc aluminum carbonate sheets, which provide a lattice-matched substrate for the self-assembly of ZnO nanorods. Selective growth of ZnO nanorods on the Al-patterned substrate as well as the high-density coating of carbon nanotubes by ZnO nanorods along the tangential and radial walls has been demonstrated using hydrothermal synthesis. The interfacial chemistry involved in the growth of ZnO and hydrotalcite-like zinc aluminum carbonate sheets is also discussed.