I have no Datura in my collection, though from your description I would venture to guess that it maybe just too much
fertilizer and rain. I would let the soil get almost bone dry then flush the soil well with tap water. Repeat again the next
time the plant needs water. Also, I would check for insects.

Just an personal observation, I do think Datura is not a plant that requires high feeding and does better on only occasional
fertilizer or I may be way off base here. ;-]

I agree, sounds like too much fertilizer
I would flush sooner than later
But thats just me.

Ted

I have a plant that's already 2 years old, stays outside in a huge pot with geraniums, morning glories, and petunias. It comes back every year because I let the seeds fall inside the pot and if they land anywhere I just throw them in. The answers above me are sage advice, I'd do just that, this plant is super easy and Loving, doesn't require nothing but water. I live in Dallas, TX so I use Miracle-Gro just a few times a year. Early Spring,Fall, just before Winter if it gets very cold, during the Summer I'll use it in June then in August, but I also use Miracle-Gro potting soil and water every day if my plants and flowers need it. I like the liquid version of Miracle-Gro better, just don't pour it on top of the plants only on the dirt, I also sprinkle insecticide over them for ants and insects. Sometimes the leaves will curl up when it's too hot.

Hope this helps, good luck~ Garden Lover