ZnO nanowires were synthesized by wet chemical methods on various ZnO templates, including commercial ZnO phosphor microparticles, [002]-textured ZnO thin films, and well-aligned ZnO nanorod arrays with c-axis preferred orientation. In all cases, the resulting nanowires were observed to grow on the (002) surfaces of the ZnO templates, along the [002] direction. A dissolution/recrystallization growth mechanism is proposed for the nanowires produced in this experiment. This improved understanding of ZnO nanowire growth has enabled demonstration of a route to forming ZnO homojunctions, using wet chemical methods to extend the lengths of individual pre-existing nanorods grown by pulsed laser deposition.