I recall when I was young (about 30+ years ago) I saw on TV a movie about a humanoid alien race which evolved from plants instead of animals. I was about 6 or 8 so I don't remember much about it, but it might have been in black and white (though not completely sure).
It had some horror tone to it, since aliens could destroy humans or something, though I don't know if it's possible to call it a "horror movie". And if I recall correctly they planted eggs or something similar to eggs to reproduce. The alien race might have been from Mars, thought not completely sure.
Does anyone have an idea which movie it could be?