When the mother of the bride is picking out her dress, it is considered traditionally appropriate that she avoid anything in the white, ivory and champagne color family so it does not appear that she is trying to upstage the bride, who is the center of attention. Others believe that black should be avoided because it indicates mourning (over the loss of a daughter) and doom. In addition, red and other “flashy” shades are frowned upon because they signify flamboyance, defiance and they draw too much attention.
However, these rules are not steadfast because there have been many occasions where moms look elegant and tailored in white. Black can also look chic and formal while red can make the mother of the bride appear ravishing while still appearing in good taste. The bottom line appears to be that there are no unwavering rules, just that any mother needs to talk to the bride to see what she thinks. She may think white looks fabulous or she may be very sensitive to it and other colors like red. If expresses any reservations or uncertainty about the color issue, go for a subtle yet stately color in the blue, rose, lavender, beige or rose family.