Hydrangea
I just loved these bright pink Hydrangeas in Andre's garden. There are blue/purple and white Hydrangeas as well. I have heard many stories as to why the flowers are different colours and decided to consult the trusted Mr Google. This is what the Wikipedia has to say on the subject:
"In most species the flowers are white, but in some species (notably H. macrophylla), can be blue, red, pink, light purple, or dark purple. In these species the color is affected by the pH of the soil; acidic which can be taken up into hyperaccumulating plants.[2][3] For H. macrophylla and H. serrata cultivars, the flower color can be determined by the relative acidity of the soil: an acidic soil (pH below 6) will usually produce flower color closer to blue, whereas an alkaline soil (pH above 6) will produce flowers more pink."
