Mine bloomed blue for the longest time, then started blooming in pink, purple & blue last year. Pretty, but I missed the blue. I'm not big on fertilizing, but during early spring, I just sprinkled down some coffee grounds and watered with left over coffee. It's just starting to bloom, and so far, the lower flowers that are just opening are blue. Time will tell though... I normally only remove the spent blooms and leave it alone until the spring, only removing branches that are visibly dead.

THanks, I googled "hydrangea" and found the answer. I copied the info: "In acid soil the blooms will be blue, pink flowers in alkaline soil, and white in neutral. The flower colors may be controlled by adding aluminum sulfate to the soil prior to budding to produce or keep blue flowers; or by liming or adding quantities of superphosphate to the soil to produce the pink ones." I'd like to add my 2-cents worth to say that the drought has adversely affected things in a big way too.

I tablespoon of aluminum sulphate in one Gallon of water...make sure all the crystals are dissolved... before the alum. sulphate application, make sure you water the hydrangea plant well..it is ok if it is dripping wet.. pour the al. sulphate solution right at the base of the plant, do not let any of the solution to touch the foliage or the leaves will get burn spots.. one gallon solution is enough for a mature hydrangea plant (3' X 3').. let the solution sit in the soil for an hr and water the plant lightly and briefly to wash off any extra solution sitting in the soil that could burn the roots... you should not apply the solution more than once every two weeks...you can apply two applications in a month and not risking to kill the plant...much more often than that, i dont know, but i won't reco it.. btw - the pink blooms already blooming now WILL NOT chg to blue even after the al. suphate solution.. the sulphates will make the soil more acidic and future bloom colors will chg accordingly.. so if you have a rebloomer like endless summer now and it is beginning to show the pink blooms, the sulphate application will not chg the pink blooms now..but the new blooms later in the season will chg to blue if the pH is low enough// if you dont have a rebloomer and all the buds are set already, an al. sulphate application would not chg the color for the blooms this season.. for me - I don't do al. sulphate applications much because it does poison the soil to a certain degree - if you have a Rhodi or Azalea nearby, they may not appreciate the extra aluminum in the soil...whenever I do the sulphate application, i do one in spring - when the flowerbuds are forming - april in that case...and another one in July for the later blooms...twice is enough for me to keep my endless summer to bloom in a brilliant blue color... have fun..

I used it last year on mine but I also used the powdered aluminum so I dob,t know which to credit with my blue flowers. I added it because my water tested alkaline. I was only using about a capful per watering can though . I would be to scared to use the cupful per gallon the article suggested. My luck I would kill them all.