cherry tree in leaf; cherry tree after blossoms have fallen
Refers to the stage after the cherry blossoms have scattered, when the tree is covered with fresh young leaves. Often used in seasonal descriptions and haiku.
When the season of cherry trees in leaf arrives, the park is filled with fresh green.
After cherry blossom viewing, it's also nice to enjoy the cherry trees in leaf.
Compound of 葉 (ha, 'leaf') and 桜 (sakura, 'cherry tree'), with rendaku voicing of さくら to ざくら.