Junior Bridesmaids Dresses ....
Traditionally the junior bridesmaid will be between the ages of 9 and 14, a time when her body is going through some major changes, look for dresses that will reflect these subtle changes with out appearing too grown up.
Try to find a dress similar to the bridesmaids. If the bridesmaid's dresses are a bit too sexy, look for a dress that will be more age appropriate for the junior bridesmaids. The junior bridesmaid should wear a dress in the same or a similar color and of the same length as the bridesmaids.(i.e., if they're wearing floor-length gowns, she should, too).
A great solution to this dilemma is to dress all the attendants in the same color, and fabric, but allow the junior bridesmsaid to choose the dress style that best suits her body type. Perhaps a higher neckline than tyhe older bridesmaid or a more mature version of the flower girls dress.
Separates work really well, they allow all the girls to wear the same skirt style, but offers the freedom to chose their own top.