Having flower girls at your wedding is a charming symbol of love and happiness. The best time to start shopping for flower girl dresses is 6 months before the event. Children grow so quickly that a dress might become too small if you buy it too far in advance. White and off-white are the traditional colors for a flower girl dress. You’ll want to select a shade of white that is in keeping with the bridal gown. Of course flower girl dresses can look charming in any color. Simply ensure that the dress looks youthful and festive.