Small shrubs as the one in the picture can be sensitive to water. If the roots stay wet for too long, the roots can rot and the plant then goes downhill from there. I would be concerned if it is always wilted.

To control moisture better, insert a finger into the soil to a depth of 2-3 inches and water only when the soil feels almost dry or dry. Add some mulch too so you do not have to water often.

A hydrangea that stays wilted even in moist soil probably has root rot (or the planting location is too windy) so monitor the soil daily (check it at the same time of the day) for about 2 weeks.

What should happen with wilted hydrangeas is that -assuming the soil is moist- the plant wilts during the day time and then it recovers by the next morning on its own. Most new;y purchased hydrangeas do this, especially during the summer months. If you see it wilted, use the finger method to check the soil and immediately water it if it feels dry; otherwise, if the soil is moist then check the condition of the plant in the morning.

Since all plants do not necessarily behave in the same way, move this plant to a more protected location so it gets less sun and less wind than the others. But keep a close eye on soil moisture.

Good luck, Luis

I was afraid that might be the issue, since it spent half a day in standing water a couple of times. Can this be combatted, or is it just a wait and see?

There is no cure. You can give the plant TLC to see if it can recover. If few roots were affected (they should be dark and smelly), you could remove/prune those. Good sanitation and cultural practices plus raised beds are what some people recommend to prevent it since most fungicides help prevent root rot, not cure it.

Here is a link that might be useful: ACES information on root rot and other diseases

Thanks for the link -- I hope to not run into that stuff, but if I do at least I'll be able to recognize some things. The droopy little guy appears to be perking up a bit. There's even some new growth at the middle of the top-most shoot, so that's encouraging. I'm paying extra-close attention to how wet its soil is, and I hope it continues to improve.

Thanks again :)

Well, my droopy little guy seems to be doing quite a bit better. There are a couple of leaves which are probably goners, but the big ones are perking back up to about normal, and there's new growth, so I think we may have turned a corner :)

Here is a link that might be useful: Updated photo of the droopy masja