Never blue

Our hydrangeas are starting to bud. They are all pink. No matter if they started life blue, they all turn pink. No amount of blue hydrangea colouriser makes any difference.
 
My grandfather used to bury rusty nails around his hydrangeas to keep them blue – I can’t remember if it worked.
 
My better half so much wanted blue hydrangeas. One year I bought a blue one, planted it in its own pot with its own potting mix, fed it blue colouring agent... We still have it and it’s a lovely shade of - pink.