We had a two-year investigation on flowering phonology,reproductive features and fruit set of Agapanthus praecox ssp.orientalis ‘Big Blue’ in Shanghai,China.We analyzed the influence of flowering phonology to reproduction from different levels.The results showed that:(1)The flowering span of population was early June to late July in Shanghai.Population duration was about 40 d and individual duration was about 14~31 d.Individual flower longevity was 2~3 d.Average flowering amplitude of two years was 6 flower·plant^-1·d^-1.Flowering percentage was 3.69%～4.87%.Average floral display was 11~17.(2)The census date of flowering phonology was late 6~9 d from 2007～2008.The curve of open flowers proportion showed two major peaks.The synchrony indices of two years were 0.663 and 0.695,it showed that the time of florescence overlap was long.The relative flowering intensity showed one major peak from 50%～70%.(3)The correlation analysis among onset,duration,flowers and fruit set showed marked relations.There were significantly negative correlations between onset and flowers,fruit set and duration.On the other hand,there were significantly positive correlations between flowers and fruit set,duration.The individual with an early starting date shows a longer duration than the individual with a later starting date.The individual with more flowers showed a longer duration than the individual with less flowers.The individual with a longer duration showed a higher fruit set than the individual with a shorter duration.At the same time,there were significantly negative correlations between the numbers of fruit from individual flower in the same inflorescence and individual flower blooming time.It showed that the sooner the individual flower open the more the fruit set.As a exotic plant,the similarity of flowering phonology within two years suggested that Agapanthus praecox ssp.orientalis ‘Big Blue’ could adapt to the environmental pressure and exhibited a steady flowering onset date and flower pattern.The longer florescence overlap and mass flowers may be regarded as an advantage to attract more pollinators and ensure its reproductive success.