Chidorigafuchi is a popular spot during Sakura season. It’s a lush green walkway along the moat of Imperial Palace with 400+ cherry trees in full blossom during the peak season . The cherry trees are planted on the slanted river bank slopes with "weeping" branches extending out towards the river ... very very pretty.
How to get there - I got off at Kudanshita Station and walked south till a bit past chidori cemetery. Alternatively, get off Hanzomon Station and walk northward along the river.