The flowering phenology and reproductive features of Caryopteris mongolica were investigated.The results showed that:(1)There were significant differences in flowering phenology of C.mongolica between artificial and natural populations.The dates of flowering phenology were also different in the same population in different years.(2)The flowering processes similarly exhibited a so-called “Mass-flowering pattern”,which might be regarded as an adaptive strategy to ensure its reproductive success.Most flowers opened before 10:00 AM in sunny days but delayed or non-flowering in cloudy or rainy days.(3)Inflorescences with more flowers showed a longer duration and more fruits than those with fewer flowers.