Belgium Botanist Charles Morren used the term Phenology for the first time in 1849 during a lecture at the Royal Academy of Science yet the phenological events were recognized and recorded many hundred of years ago. Japan and China recorded blossoming of cherry and peach trees associated with ancient festivals when changing seasons back in the eighth century.
Source: Demarée, Gaston R; Rutishauser, This (2011). "From "Periodical Observations" to "Anthochronology" and "Phenology" – the scientific debate between Adolphe Quetelet and Charles Morren on the origin of the word "Phenology"