By Steragram
Pembrokeshire,
United Kingdom 
Hydrangea pH puzzle
I have a dark red one which last year was showing a hint of blue in the centre of each floret. I added some lime and lowered the pH to just over 6. This year there is a huge increase in blueness, which is surely the opposite of what should have happened? Should I add some ammonium sulphate to try to get back to where it was? My blue one in the same bed (but without the lime) remains a lovely true blue. Can anybody explain what's going on?
9 Jul, 2014
There was another copy of this question which Bamboo and Urbanite kindly replied to - where can it have disappeared to? This one shouldn't have been there at all.
9 Jul, 2014