Oh help! What could be ailing this lilac bush?

I have a lilac hedge and they are blooming right now. But the bush on the end (as well as two specimen yellow lilacs in another part) is drooping. We have had torential rains, but it looks for all the world like it is not getting water. This bush also has only one bloom, whereas the others have put out hundreds (it is a good year for lilacs, despite the rain). It is a regular purple one.

I looked up diseases of lilacs online and I am not seeing anything obvious, unless it is a weird/rare soil fugus or bug. And if this is the case, then my other beautiful bushes might be in danger too!

What can I do? Is it serious??

Let me know if you need photos or want me to autopsy a stem or something like that. I do not see any obvious bugs-- the leaves look clean to me.
Thank you!

Lisa

Here is another perspective photo-- you can see the bush is different from its brothers.

It is a mixed hedge, with white and two shades of purples. The paler purple does predominate...

Too much water can cause wilting just like too little water can. If you've had a ton of rain lately that's definitely a possibility--wait until things dry out a bit and see if they perk up.

I also think it's too much water. I would dig down gently around the drip line and loosed the dirt around to make sure you don't have pockets that are still soaked with water.

Gosh-- thank you so much! I never would have guessed you could drown a lilac :-)

I will poke around under neath it a little bit. You have been super helpful!

There is a blight that attacks lilacs when we have a particularly cold wet spring here in the Midwest. Take some leaves in to our local greenhouse. They can check for sure and then there is a spray you can use.

Thanks for that suggestion too. If they are not perky by tomorrow (that is, if it doesn't rain again tonight,) I will take some leaves in for somebody to look at. I would hate to lose them to a blight-- I love them dearly.

There is nothing visible at all with these leaves-- other than the curling, that is. No spot, no bugs, no discoloration that I can see.

Today, after a rain-free night and a sunny morning, we are about 70% recovered, so I am going with the waterlogged option. I looked up lilac blight and looked at the pitcures closely-- for the one I found, that one leaves brown and black splotches on the leaves, so I feel pretty certain these will recover :-)

Thank you everybody!

One other thing to remember is to pull back the mulch after a really intense rain, as this can help all plants breathe little easier! We just had a major storm and I was amazed how wet the plants were under the mulch.