Not sure where you are located but heat and drought across much of the country has done a number on recent plantings (even well-established plantings) despite the frequency of waterings. And sand does complicate things with the need for very frequent watering.

Just continue to water as appropriate until the fall rains begin in earnest. Paniculatas are very cold tolerant so really nothing is required of you over the winter. In early spring you can remove any deadwood (common over winter) and prune to develop form and height. You can of course remove any old flowerheads now as you wish.

Hi gardengal...thank you! You've helped me in my many postings about our landscaping project!

Ok...so I will continue watering for now. At this point, the leaves are just falling off! It sounds like I should just leave it alone in terms of the branches/flowers/leaves...and hopefully fresh growth will occur come spring!