Am 04.05.2014 12:33, schrieb Mick:
Hi all,
I split and transplanted a Hydrangea two years ago, it did not
flower last year, but does have flower buds forming this year.

Is there anything I can dress the ground around them to get blue
flowers please?

Actually it is not acidity which turns the colour into blue. It is
availability of aluminium for the plant. Most soils contain enough
aluminium but in a neutral or alkaline situation it is not available for
the plant. Making the soil acidic or adding aluminium salts like
aluminium sulphate allows for the formation of the blue colour.
see for example http://wolmershaeuser.de/hydrangea.html
(sorry, it is written in German)
Cheers
Gotthelf

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