I have vague memory of an old (maybe 70's or 80's, it is very old) mecha anime TV show or movie that involved winged aliens and one scene in particular where the main guy is with an alien girl in a field of flowers and when the wind blows the flowers change colors. There was some robot martial arts action, too.
I actually revisited this several years ago because I remember the scene with the flowers. The show is called Tosho Daimos, or "Star Birds" in the English localization.
I haven't seen the entirety of the TV series, which is 44 episodes, but I've seen an edited version of the TV series released as a movie on VHS that's dubbed in English. I'm not sure if this is the same thing as what Anime News Network lists as the "Tosho Daimos movie".
The scene with the flowers occurs in the movie around 30 minutes in:
The petals are pink on top and yellow underneath, as the kid pointed out.
"Kelly" and "Erica" in a field of flowers.