I would do notheing....perhaps move a bit of the silt....but the fact that they bloomed well this summer tells the story.
The "florist" is obviously trying to feather his nest....or knows only about cut flowers ordered from a wholesale company and nothing at all about growing them.
I am reminded about a "professional" who told my neighbor, about a tree that plainly had a fungal disease, that it had "tree cancer" and there was nothing to do for it. AH yes! He now has a job as an elected county official....why am I not surprised?
Linda C

I'm guessing that 'florist' might not be the correct term, but landscaper? 200 sq feet is a very small area....I would certainly think about removal of the silt and letting the plants be.

I would also address the problem that caused this to happen.