Rikugien Garden

Rikugien (六義園) is often considered Tokyo's most beautiful Japanese landscape garden alongside Koishikawa Korakuen. Built around 1700 for the 5th Tokugawa Shogun, Rikugien literally means "six poems garden" and reproduces in miniature 88 scenes from famous poems. The garden is a good example of an Edo Period strolling garden and features a large central pond surrounded by manmade hills and forested areas, all connected by a network of trails.

Rikugien is quite spacious, and it takes about an hour to cover the garden's entire network of walking paths at a leisurely speed. The trails wind around the gardens, through forests and open lawns, and lead to several teahouses which are open to the public. Fukiage Chaya teahouse along the pond's northwestern shore is a nice place to take a rest and have some tea (500 yen).  

One of the best times to visit Rikugien is in autumn when the numerous maples trees turn the garden into one of Tokyo's best autumn color spots. The views are particularly beautiful around the stream that runs by the Tsutsuji no Chaya teahouse, around the Togetsukyo Bride and from the Fujishirotoge viewpoint. The colors typically appear from late November to early December.
Rikugien is also nice to visit in spring when the various flowering trees and shrubs bloom around the garden. The most notable are the weeping cherry trees near the main gate which typically bloom from late March to early April, and the azalea bushes planted along the shore of the garden's large central pond which are in bloom from April to May.
 
Source: http://www.japan-guide.com