I rotated a movie, imported, rotation doesn't hold and returns to original in imovie

I shot a video mostly in landscape but half way through switched to portrait, I want to turn this so landscape for whole video. I have cut the middle section, cropped and rotated it and saved it, then imported it into imovie but it has reverted to it's original orientation. I don't have the menu to crop within imovie. Help please?!