Well, there is still a chance that they may survive but we will not know. They are definitely suffering from transplant shock and a little from the high temperatures (35) in Australia this time of the year. High temps will cause the leaves to limp as in your last picture although lack of water will do the same. The main cause of the problem here is that part of the root system was cut during a hot part of the year and what is left of the root system may not be able to support the growth above ground.

I would plant the hydrangeas where you were planning to put them. A location with well draining soil & morning sun (or dappled sun) will be fine. Then mulch them with 7.5 to 10cm of any kind of acidic mulch. You need to keep the soil moist as much as possible without making the soil wet or dry. With plants that are this stressed, I would do that manually instead of watering every "x" number of days.... Insert a finger into the soil to a depth of 10cm and only water if the soil feels dry or almost dry. Write down in a calendar when do you water them. After 2 weeks of doing this, observe on the calendar how often you water and set the sprinkler to water 3.75 liters on that same frequency.

Wait one week. Then look at the plants again. See if any of them have improved. If one of them has not, prune off maybe about 1/3 of the stems on plants that look bad, like the one on the top photo. I think the plant on the last two photos may not need to be pruned and could recover with enough moisture.

Do not apply any fertilizer or coffee grounds this year. Just keep them on water or some liquid seaweed.

Thanks Luis!

The second plant is making it I think. But only half of it is. The other side of the plant has dry, curling leaves now. But I will give it time and see if anything else happens! Thanks a million!

Good luck, athrael. One thing that occured to me afterwards is to mention something about windy places. Windy days tend to make hydrangeas wilt or limp. If the place where you have these plants can get windy, you may want to protect the shrubs if you can with some kind of wind breaker or maybe water the day before. Our weather forecaster will advise when tomorrow will be windy and I water the night before if I am aware of that.

Oh thanks Luis! It does get windy here. Our balcony or terrace is like a wind tunnel. We have had palms before in pots and the wind is strong enough to over turn the plants. Thanks for the advice though. Will definitely keep it in mind :)