They do not seem to need anything special, just a neutral reasonable fertile, well drained soil. I would go for a soil based compost though for any shrub in a pot.

agree and dont forget to feed it too. every year or 2 with tub shrubs I remove the top 2-3" of compost and replace it with fresh. hope this helps.

Lovely variety - enjoy!

Just looked this one up and it is lovely, another for my list!

thanks owdboggy and seaburngirl for the info on compost. I would have more hydrangeas [loads!] if I had room for them, and I envy those of you who do.