Hello, katsmeow624. Newly planted hydrangeas suffer from transplant shock and, until they become established in your garden, you will see these frequent wilting episodes during the worst of the summer season. As they get older, they have less episodes. The good news is that, as long as the soil is moist, they will recover on their own by next morning (but usually by night fall).

The best approach to follow is to continue your watering regimen but monitor them in the afternoons. If the wilting episode seems extreme, immediately water (1/2 gallon of water) from the root ball outwards. Otherwise, insert a finger into the soil and see if it feels dry or almost dry. If it does, add 1/2 gallon of water. If it feels moist or wet, do not water but check it again in the morning. If it still remains wilted in the morning, add 1/2 gallon of water. Do not count these emergency waterings as part of your watering regimen but as extra/free ones for the shrub.

To minimize the frequency of these wilting episodes, make sure that the shrub has 3-4" of mulch up to the drip line. Add 1 gallon of water during each of your waterings.

You can use the finger method to help decide when to water and how often to water. Use it daily for about two weeks, always early in the morning. Each time that you water, make a note in a wall calendar. At the end of the two weeks, review the information on the calendar and determine -on average- how often you had to water. Every 2 days? Every 3 days? etc Then set the sprinkler to release 1 gallon of water early in the mornings on the same frequency. If your temperatures change 10-15 degrees and stay there then retest using the finger method for two weeks again.

Luis