Looks like the blooms were a bit heavy for the stems. You could try staking them, if you prefer to see them upright. I use bamboo, but a regular thick stick that fell from a tree would do too. Appropriately sized tomato cages work well too, but might be a little difficult at this stage.

You can also get the plastic stakes in different lengths (3', 4', 5', 6', and even taller) at the big box stores and twine or twist ties. I had to tie up my Annabelle(s) and some of my oak leaf hydrangeas due to the weight of the blooms.

You can also try using a roll of 3-4' tall green-colored rolled wire fence.

1. Using wire cutters, cut it down to 12-18" high sections and long enough to either wrap around the plant or follow the contours of the edging/sidewalk.
2. Cut the bottom-most horizontal tines, leaving only the vertical ones.
3. Stick the vertical tines in the ground in a fashion where the fence will stand straight up.
4. Rest the stems gently along the top of the fence and "arrange" them in a way that looks decent enough.

Doing it that way is a beat easier than staking stems. With heavy rains, etc. the blooms will "stack" on one another, but at least they won't look as bad as being ON the ground itself. Beyond that, by the time the blooms have expired, new growth should be growing up toward the sun from stems that have fallen horizontally, which may make for a rapidly expanding plant, especially if the flattened stems re-root themselves in surrounding soil...

Beyond that, with the deluge of rainfall the eastern US has had so far this growing season, I'm not going to run myself ragged staking everything up. It's really BAD these days. Sometimes you just have to take the good with the bad!

PS: more mature plants are less likely to flop since they can produce thicker stems each year, with old wood canes being very rigid and supporting the neighboring ones...