I love peonies, but I have had a terrible time getting the bright, vivid blooms I prefer. I have planted peonies that where supposed to be a deep red or pink color only to have them to turn out to be a pale pink shade. I plant them in full sun as directed and expected them to be the color that was shown, but I always get a much lighter shade. Do peonies need to be treated with special chemicals to achieve more colorful blooms?