By Alextb
London,
England 
The caretaker where I live noticed that my hydrangea has started to get a slight pinkish tinge to it's petals and said that I should put a rusty nail through it's roots to change it back to blue.
Does this really work, and are there any other methods?
I think ihave heard of rusty nails and blue flowers before.
Any advice welcome
Thanks in advance.
(The photo was taken when it was brand new so the pink tinge cannot be seen in this photo.)
6 Jun, 2011
Sequestrene iron tonic works - comes in sachets, mix with water, apply a couple of times a year. Dump your coffee grounds round the base too, they're mildly acidifying - the pinkish tinge means the soil's not acidic enough to maintain the blue colour perfectly.
6 Jun, 2011