Hi Linda, The bloom from the Datura will only last a day or 2 and they will droop in the heat of the day. I move mine into the shade in the hottest part of the day and the blooms will perk up. If you dont want more seeds
remove the seed
capsule because they will put an awful lot of energy into those capsules at the expense of blooms. Datura are very heavy feeders so you might want to feed it a diluted fertilizer at every watering.
A side note... When you get your next bloom, smell it in the morning then smell it again when the sun goes down, it seems that the perfume really increases at night. I have a double yellow and the scent at night is intoxicating!