flower-viewing curtains
Refers to curtains or drapes hung from trees or poles during a flower-viewing party (hanami), often used for decoration or to create a festive atmosphere.
桜の木の間に花の幕がかけられていた。
Flower-viewing curtains were hung between the cherry trees.
Compound of 花 (hana, 'flower') + の (no, possessive particle) + 幕 (maku, 'curtain'). The phrase is straightforward and describes the object literally.