Showa Memorial Park, located near Tachikawa, is the largest park in Tokyo. And it is host to some of the most beautiful cosmos blossoms in Japan. Cosmos is in full blossom in autumn, so now is a great time to head out to Tachikawa.
Cosmos cover over 5,700 square meters in the Cosmos Hill, which is located in the northern part of the park, as well as more in the Open Field in the center of the park.
I recommend you rent a bicycle to navigate around the park as it is rather large. There are many other flowers to view. A great place to visit with friends and family. Highly recommended!