Weather went from 50* and raining to 80* and sunny over night. Half my yard is wilted. Get the hose out but the buds may be toast....

Check!! It got watered today whether it needed it or not. LOL

It hasn't perked up once in two weeks even with all the rain we've had.

Did you take the potting soil off the roots at planting, as you should have or did you plant it with an intact rootball?

I wouldn't have planted it with any extra dirt on the rootball ... we hit clay pretty quickly in this garden.

I'm wondering if the roots were too wet because of the clay and all the rain we've had .... wettest spring in 50 years.

Dig it up and take a look at the roots. It's either too wet or dry. It should come out easy. You can't do any harm. Left alone, undiagnosed, it's a goner.
Mike

Your response appears to indicate you aren't familiar with what I was talking about. You want to plant with the same soil throughout the rooting zone, including inside the rootball, so there are no zones of differing materials that will cause water to back up when it hits them. If you have really bad drainage you need to put in drain lines to carry the unwanted water off.

Or pile looser soil on top of the existing soil, plant in that.

If that happened in my garden it would mean that gophers had eaten the roots. Tug on it. If that's the case it should be obvious.

No gophers here.

I lost two other plants in various parts of the garden around the same time that the snowbell started drooping. They were in good soil so I'm putting it down to a hard winter that weakened the plants and then the heat finished them off. Everything else in my garden is thriving so I don't know what else to think.

Snowbell is now history and there's a lovely little golden smoke tree in its place.