PamAdams said: But the one my mom had when you picked a dead bloom off of it, if you watched it. You would hear a pop and it would open a new one right before your eyes.This was planted next to the porch steps so it was pretty tall.
That sounds so cool!
Definitely not Missouri primrose...
But certainly looks like the wild evening primrose (Oenothera biennis) I'm used to seeing...
Unfortunately, not too many plants bloom while I watch.
But evening primrose do open at dusk...
But... they tend to be biennial... Which also isn't the growth habit you describe.