Without knowing where you are, I'd say that if you're wondering about "too intense" sun on your astilbe, it is, indeed, too intense :)

Astilbe do not like sun and are easily scorched. Mine get a bit of morning sun and are fine. But long exposure or afternoon sun will make them look rather crispy around the edges.

They also like moist, but not waterlogged, conditions.

Hi Donna, I am in ohio too just west of cleveland. The heat here has been miserable and not to the astilbe's liking. Get them in part shade or filtered shade and water them, then let the ground get dry. The tops of my astilbe looked terrible with the heat even in the shade this year and since the temps have gone back down they are greening out from below again. Looking much healthier now.
Good luck!
Tracy

If the sunlight levels or temps are too high or the water level is too low (or any combo of these) astilbe will go dormant in summer. When this happens to mine I just let them go so as not to stress them with "on again off again" growth through the summer. They usually return the following year.

good gardening to you

I just pruned off the older growth yesterday to allow the new growth to take off. We have recently had quite a bit of rain that we desperately needed and the new growth is looking quite good on my pink astilbes, the white flowering ones are looking stressed in the new growth now. Will let you know what happens next.

Tracy

good to hear you have some recovery. please do post follow ups.

cheers