I haven't grown that plant in many years but it may be that in other climes it doesn't require ataking. Our moist springs and gentler sun may encourage a larger, softer growth that becomes a bit floppy. One thing you could try is moving it to a 100% sunny spot (if its not in one now) with less moisture and see if that encourages it to be less floppy. Of course it would need a good amount of water until its established and fall or early spring would be the time to do that.

Or just say, heck with it and stake it up next time.

I didn't grow cupid's dart long enough to know about division.