Both of those are gorgeous! And I wouldn't worry about the color too much--I gave my prom date a red boutonniere to match my red ball gown (plus he was in all white, I had to break up the color so he wouldn't look like a marshmallow
). I do agree that white rosebuds would be the best on a black dress, especially if he's wearing a black suit/white shirt.
ETA: And who says she's desperate just because she didn't have a date already? Maybe your son's a looker and she was holding out for him.
