I have the most gorgeous Hydrangea bush in the front garden. When I bought it a couple of years ago, the flowers were the most glorious blue. I never worried about trying to keep the colour or change the colour as you can do, by putting stuff in the soil around it. I just wanted to see how it would go if I left it. When it flowered late last year, the flower heads were huge and some were blue, some were a mixture of pink and a bluey purple, some had a tinge of white. It was amazing. I haven't trimmed the flower heads off it yet as I quite like the look of them as they age and the colours that they turn. The red and green and russet look really good. I have 4 Hydrangea bushes now and they never cease to amaze me. Three are in very large pots and I just love them.
They are an old fashioned plant. I can remember my grandmother growing them and my mother also had a few. I think they have made a bit of a resurgence over the last few years, though I guess they wouldn't suit every garden, or every gardener for that matter. They are also very easy to propagate from. I had a friend visit last Sunday and I had not long picked the roses and the hydrangea blooms and when she saw them she asked me if the hydrangea's were fake. She had to touch them to be sure they were real !