Hello, this is Alice.
It’s spring time now, also the good time for Sakura! 
I went to some places for Hanami(cherry blossom viewing) these days, and I want to recommend you some places for the Hanami!
Koishikawa korakuen Garden(小石川後楽園)
Opening Hours: 9:00 AM ~ 5:00 PM
Admission: 300yen for adult
This garden is near Iidabashi Station. They have a sign for this park on the way from the station. Not too difficult to find this place.
It’s a really quiet, and nice place, you can just have a walk there. If you feel tired, you can find a bench, sitting there, enjoy your time with these beautiful trees and flowers.
Megurokawa(目黒川)
It’s an open area, NO admission and opening time. But, due to we are saving the electricity here, I strongly recommend you, don’t go there in the night time… There are some nice restaurants around this area, you can go for sakura first, then have a dinner there.
I would like to recommend more, but I only have these two places’ pictures now… Anyway, if you have the chance to visit Tokyo or Japan in these two weeks, then you will see more and more sakura everywhere! 
Alice / YADOYA Guesthouse
http://www.cheap-hostel-tokyo.com/
