The UV–visible absorbance spectrum of ZnO NPs exhibited the absorbance band in the range 371– 375 nm. X-ray diffraction studies confirmed the presence of hexagonal wurtzite structure of ZnO NPs having the least particle size ∼ 18–24 nm, with preferential growth along (101) plane. Beddomei) leaf extract as well as Plectranthus barbatus (P. In the present study, zinc oxide nanoparticles (ZnO NPs) were synthesized using Adathoda beddomei (A. Zinc oxide, a well-known inorganic metal oxide, in nanoparticle form exhibits photo-catalysis, antimicrobial behavior and is also employed in energy cells as well as sensor devices. A plausible structure dependent growth mechanism of the morphologically varied ZnO was also proposed. The structural and functional features of the resultant samples were studied and discussed with the help of X-ray diffractometry, scanning electron microscopy, high-resolution transmission electron microscopy and photoluminescence spectrophotometry. A solution exchange process was also carried out to prepare perpendicularly aligned ZnO nanorod arrays. The reaction parameters that control the surface morphologies and crystal orientations were explored. Uni-directionally oriented ZnO micro– nano structures were subsequently developed on the seeded glass substrates through solvothermal methods, by employing equi-molar solutions of zinc nitrate and hexamethylenetetramine. A uniform layer of ZnO seed was initially prepared on cleaned glass substrates by dip coating and calcination. Surface aligned, uni-directionally grown, hexagonal nanorod bundles and microrod pillared arrays of zinc oxide (ZnO), were synthesized through a simple, homo-epitaxial growth approach.