Last year I bought a Color Fantasy shade hydrangea that was a beautiful purpley magenta. When I bought the plant it had a couple of gorgeous jewel colored mop heads. I was told not to prune it at all since it sets it's flowers in the fall on old wood. If pruning you need to do so as soon as the current blooms are starting to fade otherwise you run the risk of cutting off next year's blooms. I also wanted the plant to get bigger so no pruning took place. This year I was a bit disappointed by the plant. Only one bloom appeared and it lost some of it's purple color. I don't want to make it blue so I'm not sure if adding amendments to make the soil more acidic is the answer. The bloom was still beautiful, I just hope next year I get many more.