Although black is becoming more acceptable for MOBs and guests alike to wear to weddings, ask yourself whether you want to be under scrutiny for the color of your chic new dress (because no matter how progressive the fashion world is becoming, MOBs who wear black are always suspected of harboring some ill will toward the union) or would rather have guests compliment you for how you look in a more traditional dress.
If you don't have choices of mother of the bride dresses, here are some suggestions:
More are suggested: mother of the bride dresses plus size, off shoulder prom dress, cocktail party dresses