Phenological events such as cherry blossom viewing and autumn foliage viewing have great potential to promote the inbound tourism market in Japan. During the period of phenological change of plants, many people are interested in the best time for viewing plants. Therefore, we conducted the phenological observation of three ornamental trees (Yoshino cherry, Japanese dogwood and Japanese maple) during flowering, leaf flushing and leaf abscission period, and the variation of plant phenology was recorded from individual tree-level and branch-level. In addition, questionnaire survey was conducted to understand people’s psychological evaluation of best viewing based on the angle of amount and color preference of plants. The results indicate that more than 80% of blossoms was preferred by most of people during flowering period; green leaves reached 100% and fully expanded was most popular during leaf flushing period; 60% to 80% of full color red leaves remained on the tree was preferred by people during leaf abscission period. However, there were differences among nationalities of people. In conclusion, best viewing of plant phenology must be varied among nationalities, besides people of different nationalities have different preferences for seasonal tourism activities.