Isn't chemistry fun? I wish I had paid more attention in high school when we were doing pH and titrations.

I tried for 2 years with an ES hydrangea in a pot and it was always pink despite my best efforts. I heard Minneapolis has high pH water and during the summer I had to water that darn thing at least once a day. I never did try the vinegar in the water thing. So I gave up, put it in the ground and now it's purple/blue color.

Sorry I can't help.

Please forgive me if my logic is incorrect...
If I recall correctly, blue is from bases, and pink from acids, right?
If so, adding vinegar (acetic acid) to your water every time you water is neutralizing your additions of al sulfate and fe sulfate. pHs lower than 7 are acids, and higher than 7 are bases. So, in my opinion, if your water has a higher pH, you are actually getting closer to Nikko blue if you leave it alone. Try quitting the vinegar, and see if it helps!
Good luck!

This is advice given to me by a woman whose hydrangeas are my inspiration in gardening--absolutely beautiful! She has beautiful hydrangeas of every color - and some outstanding blues.

She told me that she found a certain grouping of her hydrangeas had the most beautiful blue colors and when she went to go dig one up to transplant it she found that they were planted in a location where the construction workers (newer house) had dumped their soda cans. The hydrangeas roots had worked in around them. So from that point on, she always planted an old soda can in the hole with her hydrangeas.

I've started doing that, but this will be the first year that I'll get to see the blooms. Just something to consider as you try to get the blue out of your nikko. Good Luck!

Acid/Aluminum = blue
Alkaline = pink
In between the two is purple.

Thanks for the input. Colors are supposed to be easier to manipulate in pots than in the ground, but the pink despite everything as acid as I can make it seems to defy logic.

I may try the stronger aluminum sulphate solutions discussed in the other posts on just one plant.

My DH asks me daily if I've won my battle against Mother Nature. My reply to him is not fit for a polite message board. Thanks again.

The ES website also recommends: Adding large amounts of organic matter, such as peat moss and composted leaves, will acidify the soil as they break down.

So far, I have tried diluted soil acidifier on my F&E - it was so small, I didn't want to kill it! It is just starting to bloom pink. I will add some peat moss and more acidifier and enjoy it either way. Really wanting blue though!

oops, my bad. Guess that explains why mine are always pink! Hee, thanks for not hanging me up for that one!

I have a shady spot in the back yard that I wanted to plant some hydrangeas in to give me some eye level and lower color. I happened to have a friend of a friend over who is studying to become a master gardner. I really don't want pink flowers in my yard so I asked him what I should plant to get purple or blue flowers. I have 10 mature pecan trees on my small city lot so my yard is extremely acidic. He told me that I would only have pink flowers unless I totally amended the soil. I believed him and was looking for something else to plant--goes to show you shouldn't believe everything you're told.

Thanks for clearing the acidic/base thing up for me.

De

Thanks for the feedback. I may just have to content myself with whatever color they are since doing all the "right" things for blue obviously isn't working. I'm sure there's a life message in there somewhere.

Is it really twisted to consider, when house hunting, a potential new home's orientation and shady spots to grow hydrangeas in this climate? Pots on front porch are my only current option so they don't get scorched.

Happy Sunday gardening to everyone.