A couple of photos would help since different problems may look different, at least one showing closeups of the damage and one that shows the entire shrub.

It might just need a different location in the garden. I'm guessing it doesn't like what it's growing in.

Get the bats out of your attic. The attic is filling up with guano too.

Bare-root and put it in the ground somewhere far from the bats.

i would be more worried about the bats.

Why would bats be a worry? They will be busy vacuuming up insects, including mosquitoes, all over the area. Don't know about the US but all bats are protected in the U.K. If you have them in your attic you have to get in the experts to advise on how to deal with them. Turfing them out is not an option.

Well, that's not the case in my part of the US. The way I see it, as long as they aren't causing me any problems, they can stay. When they step over the line and cause problems, they're dead.

Bats are a protected species, at least in my state. They cannot be removed during maternity season (approximately mid-April through August 1, I think). They serve a valuable purpose in devouring insects.

In my house, they roost in the attic vents, which are covered on the inside attic side with wire mesh, thus preventing them from invading the attic. Although most of their guano falls to the outside ground, some does fall in the periphery of the attic. Thus, I agree, they need to be prevented from roosting in the attic vents. The apparent solution is covering those vents on the outside with mesh, which, again, can't be performed during maternity season.

As far as my original post about the spirea in a pot: it is beginning to get new leaves. So thanks to anyone that tried to help.