I'd guess that watering, specifically not enough, is the primary cause of your problems. Plants planted in late spring in full sun will need frequent deep waterings (not a daily sprinkle) to keep the rootball adequately moist. Inadequate soil moisture coupled with high humidity can also be the recipe for powdery mildew, which the white powder-looking stuff may be. Would need a photo to confirm.

Neither the powder nor the munched leaves constitutes anything more than some minor cosmetic damage. The plant is tough enough to grow out of it with ease. Just keep it properly watered.

Hi & welcome to Gardenweb.

Agree with gardengal, it just needs a chance to settle in. The fact that it's still alive since Mother's Day makes me very confident that it will pull through.

In general, BB's don't need much care once established. Just trim the dead flowers so new ones appear. Wait until spring, when new growth is starting to prune for shape and size. Fall pruning can be fatal to these short-lived shrubs.

The pieces you trim can be stuck in the ground for more bushes. I try to start a couple new ones somewhere every year because you never know when your BB will just die. From what I've read over the years on here, the farther south you go, the less risk of mysterious death (which I think is usually attributable to being too wet in the cold when people have trouble with them) but having just 1 BB can be very disappointing if it happens to you.

Thank you so much for the advice. I don't have hose access where the bush is planted, but I have started watering it vigorously via buckets of water and it is already starting to look better and less "wilty."

I'm so glad to have found this forum and, again, appreciate the helpful advice! :)

Glad it's looking better!

You and your BB might get the most benefit out of water you have to carry by putting a milk jug at the base of the BB. Cut the top off of the jug so you can pour into it easily, and put a pinhole near the bottom on the side. As the water dribbles slowly out of the hole, it will be slow enough to be deeply absorbed right where it's needed. If it takes an hour or two to drip out, that's good. If you put the hole high enough that about an inch of water stays in the jug, it might not blow away. Might need a rock too so you don't have to go looking for it next time you water.