ZnO nanobundles were grown via a nano-templating technique over a porous silica bed using an aqueous chemical route. The growth of nanobundles initiated from ZnO nano-seeds positioned at various levels over a nanoporous matrix of self-assembled polymethylsilsesquioxane nanoparticles. Bundles of different features like nanowires, nanorods and nanotubes with a high surface roughness were grown over these templates by a day-long incubation in an aqueous solution of hexamethylene tetra-amine and zinc nitrate. We envisage these ZnO nanostructures for sensitive hydrogen detection. Photoluminescence spectra indicate the nanotubes to be most sensitive towards H2. We observe high reconditionability, moderate sensitivity and a temperature dependent charge carrier reversal phenomenon. © 2014 The Royal Society of Chemistry.