I have a 5or 6 yr old endless summer and it really does need the sun. I just moved it to a location with less sun and this has really lessened the flowering. The leaves are fine, just fewer flowers. All in all I've been very happy. It hasn't been that hard to keep it blue even though I have moderately alkaline soil naturally. I just add some garden sulfurin the soil around the root ball. It will wilt when the heat here approaches 90+ but then it just snaps backs as the temp cools. If you google endless summer hydrangea and look on the site for "growing tips" you may get some more info. Lastly don't cut it back to the ground like you would an annabelle. JUst cut off whatever wood looks dead. I usually wait and do this bush after it has just started to grow again in spring so I can see what is what.

is the compost ok around it? and how do I make it blue again???right now I have pink flowers on the new plant.
Question..My neighbor has hydrangeas that have blue violet and pink flowers all on the same plant!!!!
why?

Yes it is more then ok to use compost when planting your hydrangea, infact i high encourage you to do so.

I planted three ES hydrangeas (2 original & 1 Twist n Shout) this spring and they are doing well considering all the moisture we have been getting. I too have alkaline soil (clay) and i added some composted manure as well as garden soil and native soil when planting. My hydrangeas get sun till about 3 pm right now and will wilt if it gets hot outside but that is natural for them to do so.

More then likely your neighbor has been adding aluminum sulfate or lime to his hydrangeas and that is how he is getting the different shades of blooms. Go to endless summer's website and it explains how to do it. A word of caution is that a little aluminum sulfate goes a long ways.