The Lightning Tree (2010)

Set during the Edo Period, a young man from a noble family meets a young woman under a special tree called "Raiou" (the tree was struck by lightning at one time with the broken part eventually sprouting out cherry blossoms). The young woman lived freely in the mountains after she was abducted as a young child. The couple soon fall in love under the Raiou tree, but become acutely aware of their different social positions & the ramifications it has on their relationship.

Unfortunately the movie The Lightning Tree is not yet available on HBO Max.