Phenology events are important to the reproductive success and long-term persistence of plants in a given environment. These events are considered to be highly plastic due to their flexible response to environmental cues and have therefore gained importance in the context of climate change. A high variation in flowering time among species occupying similar environments indicates that phenological responses may be additionally mediated by pollination. Hence, the segregation and aggregation among different species may be associated with the biotic interactions with pollinators. In addition, evolutionary relatedness among species has provided insights that if closely related species share the timing of phenology events then species decline may not be random or uniform, but rather biased towards certain clades. However, these responses and relationship is complex and more studies are required, especially in mountain regions where the impact of climate change is profound. The role of abiotic and biotic factors and evolutionary history were tested on the reproductive phenology traits of 10 locally aggregated high‐elevation Rhododendron species - R. campanulatum, R. campylocaroum, R. hodgsonii, R. thomsonii, R. cinnabarinum, R. anthopogon, R. aeruginosum, R. lepidotum, R. wightii in Kyongnosla Alpine Sanctuary, Sikkim Himalaya. The study was carried out between 2013 and 2015 across an elevation gradient of 3400 to 4230 m The timing of reproductive events (budding, flowering, different stages of fruiting and fruit dehiscence) and their durations were monitored for the study species and their responses were measured against bimonthly mean temperature and day length. Community phylogeny was built in order to examine how it affects phenological progression. The early phenology events such as budding, flowering, and initial fruiting, which occurred during the favorable month of the year, exhibited strong phylogenetic signal and were mainly associated with day length and temperature.