Sailor Moon R: The Movie: The Promise of the Rose (1993)

Fiore, an old friend from Mamoru's lonely childhood who couldn't survive on Earth, returns with flowers he promised Mamoru. But, the evil flower Kisenian overpowered Fiore's weak mind and manipulated him into spreading Kisenian's seeds over Earth in an effort to drain energy from everyone on Earth. Kisenian manages to do this because he's deceived Fiore using Fiore's long-lost friendship with Mamoru. It is up to Sailor Moon and the Sailor Senshi to stop Kisenian.