I have replaced stone damaged condensers on late model Lexus vehicles, but not on 7th generation ES.

Most manufactures use proper grill screening on the lower half of the grill for protection from road debris, it seems they didn't consider this on the ES.

The ES350 is good at collecting trash, I see this on many ES350s during the maintenance visit at the service department. Below is a picture of a customer's car.

 

I believe some people install a screen of sorts as sort of a pre-filter to deflect rocks, debris, and such. You may want to search the aftermarket to see if they make one for your car. Obviously they're purpose designed and allow air flow. But might provide some protection against rocks

 

I had the same thing on my car. I had to pull back the upper valance with the hood open and wedge the vacuum cleaner hose down to suck up the leaves..