GaN nanowires are grown on Si(111) as templates for pendeoepitaxial coalescence overgrowth under different V/III ratios by molecular beam epitaxy. The degree of coalescence in the nanowire template increases with decreasing V/III ratio or doping with Mg. The morphology of the GaN nanowire template strongly influences that of the pendeoepitaxial layer after coalescence as well as its optical quality.