Can you post a pic of it? Give it some water and see if it perks up. The soil may be different on either side and check for spider mites or other bugs on the undersides of the leaves.

Here is the pic of the wilting datura, the one on the left side of the mailbox is doing great! The right...droopy. Just wondering if I should just back off of watering. Looked closely with magnifying glass...no insects.

Here is a link that might be useful: Wilting Datura

Looks like a root problem as these things will grow in cracks in a rock, buy a soil test kit

smurfy,
what is a soil test going to show me??? I don't know what to look for on reading for the health of a Datura???

Check the soil around it and see if it's raised up. Could a mole have run under it ? One did mine, and it just fell over because it was so wilted (the roots were in it's path). I tried pressing the soil down and watering, but it was too late. Maybe it's not to late for you... Edna

Looks to me as though it is from the heat? This one is closer to the blacktop, maybe it's throwing off too much heat at it.

On the other hand..it looks as if the soil is sinking behind and to the right of it? WHat's that about?

Another thing I am thinking is that maybe, the tar is having some kind of effect on it. I see how the edges of the driveway are breaking apart a bit..maybe some of the chemicals are leaching into the soil from those broken pieces and the plant is taking it in?

Hmmm....the soil didn't seemed raised at all by moles in spite of the fact that I've had many everywhere else!!
The dirt is actually pretty even in that location...it has mulch piled around it...doesn't really slope enough to matter. As for the asphalt...I suppose that could be possible, I've planted in this location for years now and nothing else seemed to be bothered by it. Pretty strange to me....

Well, just like a mom with her first new born, I over reacted to the wilting....we just had a thunderstorm, plenty of rain. Went out to check on it, standing straight up and another bloom was open!:-)
Now I learned that it's thirsty more than anything. I'll have to keep a closer eye on this one. Thanks all for your time and input.

Here is a link that might be useful: Datura Revived! Hooray!

I had a similar problem with some brugs. Finally traced it to gophers. They damage some roots as they make their way. Extra water cured it until they made more roots. The more it rains the more they tunnel.

Daturas are pretty hard to kill once established.

Glad it all worked out. I know some of my plants that are 2 feet away from others need more water for some reason. Maybe the soil is different or near a hotter surface or something digging who knows.

Take care not to over water, it likes it drier than a
Brug. Last year I had a great on going but since it was in a bed that had to get allot of water, I could not keep it on the dry side, and it died. ~~was a biggie too.