>>92689237I've always assumed that the Moonflowers' emotional effects only manifest from emotions that are being felt for productive reasons. Hanazuki's first treasure reacted when she was upset that the Hemkas would rather fight over things than come together and help each other: Her anger was justified. Stuff like that.
Kiyoshi's dilemma seems to be that he feels he's a failure at doing his job protecting his moon. His despair is fueled by a positive, justified concern over the safety of his moon, though it's unclear if black trees actually repel the Big Bad or not. Kiyoshi certainly thinks they don't.
Kiazuki meanwhile certainly feels anger, depression, even fear and more, but has she felt them in any meaningful, justified way? She seems to feel emotions out of pride, rather than out of concern for others.
I guess we'll see in the coming episodes if my theory holds up, or if it's just that she's a bitch.