curtains hung during a flower-viewing party
Refers to the decorative curtains or fabric panels hung from trees or poles at a 花見 (cherry blossom viewing) event, often to define a space or add festivity.
公園の桜の木に花見幕がかけられていた。
Flower-viewing curtains were hung from the cherry trees in the park.
Compound of 花見 (flower viewing) and 幕 (curtain). The exact historical derivation is uncertain, but the term straightforwardly describes curtains used at flower-viewing gatherings.