[en] Highlights: • Synthesis of hierarchical ZnO generates flower-like structures by a formation mechanism based on oriented aggregation • The obtained ZnO hierarchical structure improves the antifungal activity • The improved antifungal activity is due to low participation of chemical interactions favouring a purely physical mechanism The interest that awakens the ZnO as material is greatly extended both by its unique properties as by its wide variety of applications. Within these applications, antimicrobial activity is gaining relevance. Especially, the bactericidal activity of ZnO nanoparticles is outstanding but little is known about antifungal activity. In addition, the recent discussion about the potential toxicity of nanoparticles and their massive use places them in the spotlight. In response to this emerging problem, a simple and general approach to synthesize hierarchical structure of ZnO is reported. A formation mechanism of these surprising structures is proposed. Moreover, the obtained zinc oxide hierarchical particles improves the antifungal activity towards Aspergillus niger in contrast to ZnO micro or nanoparticles. Due to surprising results, the different action mechanisms of ZnO hierarchical particles against fungi are studied. Thus, we pose a novel physical mechanism by which ZnO hierarchical particles achieve excellent fungicidal results.