Coral Bells Are Sure to Delight Mid Valley Times Dressed Up 'Prom Dress' Coral Bells Heuchera hybrid Proven Winners Heuchera 'Prom Dress'. This new member of the DRESSED UP Series has large, ruffled, pewter leaves with charcoal veins. I've been happy with the other two members of this series, 'Ball Gown' New this year! Dressed Up 'Prom Dress' is the newest member of our collection of large, heavily ruffled coral bells whose size and unique texture makes them easy to pick out