My mom has a whole garden of ES..and from what I can tell, ES (and Nikkos - she has a bunch of that too) needs a lot of water during hot summer days...relying on just moderate rainfall probably won't be enough...here in New Jersey, we have some soaking rains every now and then, only after that, we stop our regular waterings of the hydrangeas...in hot days like we had two weeks ago (98+ and no clouds in the sky), we watered the ES and Nikkos twice a day (early morning and dinner time)..and we have minimal wiltings...ES is not even forgiving when it comes to the hot afternoon sun and it needs a lot of water. In her garden, mom is trying out the Cityline series of Hydrangeas and it seems they are more sun tolerant and no wilts even during the 98-102 days we had two weeks ago..but they do get sunburn though if if you them under the afternoon sun with no shade (just as all other big leaf Hydrangeas would). BTW, my mom fried her very first ES whne she forgot to water the plant for two days and exposed it to the afternoon sun (in one of those 90+ jersey summer days)...that plant didn't perk up after some serious soakings and we knew it was beyond help then...if you plant perks up after a good soaking, you should be fine..maybe get some shadecloth drap over it during those very hot cloudless days..jmho.

thanks, that's very helpful!

ES will wilt until the root system is developed. I decided I couldn't stand the wait four years later and moved mine out of the afternoon sun. No wilt this year, so far...