Koishikawa Botanical Garden (小石川植物園, Koishikawa Shokubutsuen) belongs to the nearby Tokyo University, Japan's most prestigious university. It exhibits and preserves a few thousand tree and plant species and includes a beautiful Japanese landscape garden.
Koishikawa Botanical Garden is also one of Tokyo's most pleasant and interesting places for cherry blossom viewing, because it does not get as crowded as other hanami spots and features cherry trees of various species. However, it is not to be confused with the similarly named Koishikawa Korakuen.
Koishikawa Botanical Garden is a 10-15 minute walk from either Myogadani Station on the Marunouchi Subway Line or Hakusan Station on the Mita Subway Line.