Blossom was Fred Ferguson's lover, who was infact using him to get the money his wife Monica Ferguson was hiding for Joyce Martin, and actually working with Bruce Starr. They rob the money, but are soon arrested in their motel room by Inspector Grace.
Blossom winds up in Wentworth however, and Monnie is furious to find out she was having an affair with her husband Fred.
Blossom steals the key to the safety deposit box hiding the money, and hides the key in the shower block.
When she is released, she tries to seduce Jim Fletcher into helping her. She refuses to tell him, unless they have sex. Despite the rules against contact with ex criminals, it's implied that the two indeed have sex. Blossom eventually reveals where the key is, and is double crossed by Jim, who intends the reward money to help his family and his (separated) wife.
This is the last time we see Blossom.